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1. Digital Atmosphere METEOROLOGICAL ANALYSIS SOFTWARE USER MANUAL Digital Atmosphere USER MANUAL Edition 001 May 27 2007 Software and documentation Copyright 1995 2007 Weather Graphics Technologies All rights reserved Information in this manual is subject to change without notice and does not represent a commitment on the part of Weather Graphics Technologies The software described in this manual is furnished under a license agreement The software may be used only in accordance of the terms of this license agreement It is against the law to copy this software on any medium except as specifically allowed in the license agreement No part of this manual may be copied pho tocopied reproduced translated distributed or converted to any electronic or machine readable form in whole or in part without prior written approval of Weather Graphics Weather Graphics Technologies P O Box 450211 Garland TX 75045 800 840 6280 Our E mail addresses are located at http www weathergraphics com contact htm World Wide Web www weathergraphics com CONTENTS Tutorial 1 Setting up our area of interest 1 Loading some weather data 2 Make sure we re at the surface 3 Looking at the big picture 3 Adjusting the map amp adding content 3 Measuring distances 4 Looking at station plots 4 Cutting down on crowding 5 Overlaying more contours 5 Seeing the wind flow 6 Conclusion 6 Display com
2. NEXRAD Level II ICD 2620001 WSR 88D NEXRAD format Australian AXF comma delimited observational data and similar for mats NHC Hurricane Warning bulletins System requirements Operating system Windows 2000 XP or Vista Processor Pentium or better recommended RAM 128 MB or better recommended Disk space Minimum 50 MB Source of data Internet access recommended which allows access to any of numerous free university and government data sites Special notes Windows 3 1 Win32s and earlier versions of Windows are not supported Compatibility with Windows 98 and ME is unknown compatibility with Windows 95 is unlikely Other information Lines of source code 152 217 lines totalling 2 01 MB as of May 2007 Langauge written in ObjectPascal Date of original release January 1 1996 Predecessors WeatherGraphix MS DOS released 1993 WeatherPro MS DOS released 1992 RadarScan MS DOS released July 4 1992 SFCPLOT PRG C 128 created 1987 DID YOU DOWNLOAD A COPY OVER THE INTERNET Copies of Digital Atmosphere downloaded over the Internet are 30 day trial versions They are fully functional version for 30 days There are no separate registered and demo versions and there s nothing else to download or install However you must register Digital Atmosphere within 30 days of installing it or quit using it If you don t register at the 30 day point the soft ware will disable certain features such
3. OOOO iii UMMA hhh the Frontal depiction This option allows plotting of georeferenced fronts highs and lows The features are georeferenced therefore you can always plot them later even if you zoom in or quit the program You will lose your frontal depictions if you again create a depiction or if you import original ASUS1 data Chapter Five DATA MENU 51 An important word about frontal positions Computers cannot be used to automatically create frontal positions There are only two possible ways of displaying frontal positions through an analysis entered by you see Toolbox section under Fronts and through weather bulletins created from human derived frontal positions The ability for a computer to independently analyze for fronts does not exist except perhaps in experimental form and it is a poor method for analyzing the subtleties and complexities of the atmosphere One of the reasons Digital Atmosphere was created is to help forecasters analyze all aspects of the atmosphere rather than provide a shortcut to finding fronts Even if you use frontal positions obtained by someone else you still may get contradictory positions that may not work well with your own analysis A good cautionary essay on centralized analysis charts can be found in A Case for Detailed Surface Analysis by Doswell and Sanders at http www nssl noaa gov doswell sfcanal surface_analysis html Using original sources of data Raw sou
4. J 60 K 72 L 84 M 96 N 108 O 120 P 132 Q 144 R 156 S 168 T 180 U 192 V 204 W 216 X 228 Y 240 However if A GRIB designator is Z AWIPS this will instead be A 02 B 03 C 04 D 08 etc Note that Digital Atmosphere will only process grids mapped in lat long polar stereographic and lambert conformal projections Documentation Documentation for the GRIB format includes http www nws noaa gov dataprod html http 205 156 54 206 o0so ftpgenl shtml http zephyr unl edu grids http www ncep noaa gov NCO PMB docs o0n388 tablea htm1l MMM model codes http www ncep noaa gov NCO PMB docs o0n388 tableb htm1 Grids with pole point listings http www comet ucar edu strc data model_data_summaries Lists grids w images and model codes in current use http www comet ucar edu strc data model_data_summaries osoname html GRIB naming conventions http dss ucar edu docs formats grib gribdoc pdf Complete documentation http weather unisys com wxp Appendices Formats GRIB html More documentation http weather unisys com wxp File Model_Name html http www cgd ucar edu cms eaton cf metadata ECMWF html 122 123 APPENDIX Scheduler scripting Scripting is a powerful function that allows Digital Atmosphere to do various tasks while unattended You can have it download data every half hour and always have the latest map displayed or send charts to the printer automati ca
5. J B he Mee Lim pat Ei 7 d is i k ae T na SaqtjancPlots SFC 1960 2009z Sun 27 May 07 _ ooie falar data from Canada for Alberta and Saskatchewan Set NEXRAD station Before Digital Atmosphere can access NEXRAD data from the Internet it must know which stations you want to look at A map will be displayed and you will be able to select the sites for which data should be accessed Special note Please see Special Note About Choosing Multiple Stations in the radar introduction Quick pick Allows you to quickly set a new station by typing its identifier into an entry box This is designed for advanced users Always enter the three letter identifier such as FWS MHX or CCX If there are multiple sta tions separate them with a space If you do not know what to enter or how to use this box use the Set NEXRAD Station interface instead Special note Please see Special Note About Choosing Multiple Stations in the radar introduction Chapter Seven RADAR MENU 65 Set date time The Radar Time Select module allows fast efficient display of histori cal WSR 88D American radar information often going back to 2 or 3 weeks It depends on the availability of stored radar information from participating sites as of May 2007 only Texas A amp M University does this When this menu is chosen you will see the following panel iojxi UTC date and tim KE December 2006 Sun Mon Tue Wed Thu 3 4 5
6. Early ver sions of Digital Atmosphere do not import this type of data Radar reports come from about 100 stations around the country A few years ago they were typed up by humans but most of them are now centrally generated by computer based on images from NEXRAD radar sites around the country This is what a radar report looks like MCI 0225 CELLS TRW NEW 250 195 D10 C2330 MT 300 0I22 FD winds aloft data This is not an analysis of real conditions rather it is numerical output from the National Centers for Environmental Prediction formerly NMC in Washington DC It is used primarily for aviation forecasting pur poses consisting of a coded wind and temperature forecast at 12 and 24 158 Appendix RAW DATA SAMPLES hours into the future Nevertheless it makes excellent forecasting charts in Digital Atmosphere For Hours ID Use Z From Now 3000 6000 9000 12000 18000 24000 2XG 09 18 00 09 3613 2911 06 2520 02 2430 03 2342 15 2462 26 Rawinsonde data Also called TTAA data This is the backbone of upper air observation reports sent twice daily from hundreds of stations worldwide several dozen in the United States alone It is a highly numerical coded set of data that is used extensively in meteorological operations and is used as input into the numerical forecast models Here s an example of what it looks like 72558 TTAA 69121 72558 99973 00821 30002 00130 92762 01611 03014 85444 01850 00521 70993 04159
7. H So if it was 9 pm EST 02Z Digital Atmosphere would retrieve http www weatherdata com 02data txt Here is a complete list of all the UTC time token combinations you can use Character 1 mode This hour Last hour Character 2 time M Month D Day H Hour X Rawinsonde hour rounds down to 00 or 12 S Main synoptic hour rounds down to 00 06 12 or 18 I Intermed synop hour rounds to 00 03 06 09 12 15 18 21 Frontal hour for ASUS1 KWBC frontal position bulletin rounds to 01 04 07 10 13 16 19 22 note that some servers do not produce a ASUS1 at 22Z n Although Digital Atmosphere automatically figures the current time tokens before you retrieve data you may want to override them This is handy if you want to see data for an earlier hour All you have to do is change the numters that are displayed in the time token panel Solving incorrect time problems If the time tokens always show a slightly incorrect hour check your Pref erences menu under the General tab and make sure the Daylight Sav ing checkbox is marked in accordance with whether daylight savings time is in effect If the hours are significantly off go to your Windows control panel look under Date Time and make sure your computer is set to the correct time zone Then make sure your system clock is set to a current time which is valid for that time zone For example if you live in New York and typically have your computer
8. Oklahoma These are centralized human produced forecasts issued several times a day and are used to help provide guidance to National Weather Service forecast offices They are also used frequently by storm chasers pilots and hobbyists To use this option you must have imported a convective outlook as part of your raw data set or from one of the choices in Internet gt Advanced users can modify the color scheme by changing the contents of the file DIGATMOS CCC in the Digital Atmosphere directory using a standard text editor such as Notepad never use a word processor such as Microsoft Word or you will corrupt the file This file contains self ex planatory instructions for modifying the hexadecimal numbers used to determine colors of the various threat boundaries If there are any problems ingesting a bulletin the problem is most likely an error in the composition of the bulletin It is not necessary for the header to be intact but the STORM PREDICTION CENTER title must appear in the bulletin along with the convective outlook type valid times and standard bounding locations of each threat area Sample of convective outlook Chapter Five DATA MENU 55 492 ACUS2 KMKC 041803 SWODY2 MKC AC 041801 STORM PREDICTION CENTER NWS NCEP NORMAN OK DAY 2 CONVECTIVE OUTLOOK REF AWIPS GRAPHIC PGWI47 KWBC VALID 051200Z 0612002 THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 40 ESE P0O7 BGS CDS 55 NE AMA
9. PREFERENCES 91 E Filename for this map style The file shown here is what the filename will be on your hard drive This will be filled in automatically when you choose a plaintext name However the edit box gives you the opportunity to override the filename Only alphanumeric characters and dashes are allowed E Style template filename optional Normally the new color settings will be extracted from the styles master stx file If you d like to clone a different file choose it here E CREATING STYLE FILES MANULLY You can create your own style files manually in a text editor as long as the filename ends with sty resides in the styles directory and conforms to the style formats shipped with Digital Atmosphere in this directory Incorrect configu rations may produce an error in Digital Atmosphere and prevent fields from being generated Miscellaneous 1 tab Advanced internet settings If you use a proxy host enter the name and port here If you do not know the proxy settings you will need to contact your ISP Our tech sup port personnel cannot guess these settings or look them up for you For example users of Alphalink in Melbourne Australia will notice on their Alphalink support pages that they would need to enter proxy alphalink com au in Proxy host and 8080 in Proxy port Color gradient fills This section lets you define how gradient fills will look It is designed mostly for experienced users and will requi
10. Setting and overriding radar access URLs Users are able to change URLs corresponding to the desired products This is done by editing the digatmos rad file Within this file you construct a template for retrieving the NIDS Level III radar file Only the URLs in the Default section are used under normal circumstances However you can override them by creating new sections which contain a title that starts with an equal sign To implement any radar access source set the Preferred source in Set NEXRAD Station to something besides Default If the product you request cannot be found in the override the one in the default section will be used Setting and overriding color schemes Likewise users are able to set and override color schemes To do this sim ply edit the digatmos nex file To implement any color scheme go to Set NEXRAD Station and choose something besides the default color scheme Color schemes for annotations storm tracks hail mesocyclones and so 62 Chapter Seven RADAR MENU forth are handled in the map s color table you may either edit this in File gt Preferences gt Colors or by directly editing any file in the styles directory Translucency Radar echoes are drawn using translucent polygons For best results make sure your basemap is as bright or as dark as possible Before plotting radar echoes Digital Atmosphere will examine your style file for the background color bas in Preferences gt Style
11. and recovers its cost through end user charges Though SFLOC data is publically available you must contact the data supplier to inquire about your status if you are using the information on a commercial basis The responsibility rests with the user to ensure that they are not violating any rules or national regulations The SFUK bulletin s point of contact is the British Met Office http www meto gov uk tel 44 0 1392 885680 Europe s primary lightning network consists of five stations in the UK one in Cyprus and one in Gibraltar The stations listen for static and use triangulation of the time delay to pinpoint the location This is encoded to the nearest half degree yielding a resolution of about 40 km The com monly available British bulletin SFUK has a domain of 40W to 40E and 30N to 70N The time period for each bulletin is 30 minutes and a new bulletin is generated every 30 minutes The SFUK is based on the WMO FM 32 I SFLOC code form but is adapted under a national variation The British Met Office does have a new system online that can pinpoint light ning within 100 meters however this data is not publically distributed Contact the Met Office if you need access to this data 54 Chapter Five DATA MENU 2007 Weather Graphics Technologies Convective outlooks This option plots convective outlooks thunderstorm forecasts issued by the National Weather Service s Storm Prediction Center SPC in Nor man
12. dimensions and the resulting image should come out rather sharp Memory errors If the printer shows memory errors this means that the graphic you are sending to the printer is too large to fit into the printer s memory The easiest way to remedy this is to go to File Print Setup and choose a portrait printout rather than a landscape printout Another solution is to regenerate your charts without using any color fills or topography i e totally composed of 98 Appendix PRINTING line graphics The third method of solving a memory problem is to use a lower resolution i e choose 600 dpi rather than 1200 dpi or 300 dpi rather than 600 dpi in your printer setup The final and best solution is to increase the amount of RAM in your printer by installing a SIMM memory module Your printer will require a total minimum amount of 2 MB of RAM but will work best with 4 MB or more In Windows 98 some users have reported problems printing to HP LaserJet and a couple of other printers such as getting blank pages This is usually a problem with the Windows PCL 5 print driver and is beyond the control of Digital Atmosphere Solutions for this that have been documented are changing the resolution from 600 to 300 dpi or change the print mode from vector to raster If your printer is equipped with a PostScript option always use the PostScript mode for 600 dpi printing Overall this printing problem is not specific to Digital Atmosphere
13. has ncdc noaa gov plclimprod plsql HAS FileAppSe lect datasetname 6500 but is not compatible with Digital Atmosphere at this time View radar data This function will display any radar data that has been recently import ed You can use it to redisplay existing data without causing the system to download new radar data Chapter Seven RADAR MENU 63 Load radar data Rather than accessing new radar data through the Internet you may load the data from an existing file Any NEXRAD data in this file will be imported and automatically displayed You may save data to be loaded and viewed again at any time in the future by using the Save radar data to file command Save radar data Saves any imported radar data to a file of your choice You may then view it again later by using the Load radar data from file option Advanced users This basically copies the queue nid holding pen to your desired location Import radar data This is a powerful interface that allows any graphical radar image to be georeferenced and mapped into Digital Atmosphere This gives tremen dous flexibility with importing radar images from international weather service agencies which withhold raw data The list of available radar resources is kept in the file digatmos rdy and may be edited See the appendix section Importing Radar Data for information on how this command works 64 Chapter Seven RADAR MENU 1 ae mae x a D a
14. 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 lt P ZD Today 1 2 2007 Time hh mm 00 00 J OK If Use current real time radar data is enabled Digital Atmosphere will function normally and no archive operations will be conducted If it is disabled then Digital Atmosphere will use the date and time selected to find archived radar information online whenever a product is chosen in the Radar menu The Preferences gt General gt Radar Source dropdown must be set to a designated radar archive source typically Texas A amp M University We have configured digatmos rad to work properly with this data source Base reflectivity Shows the most common radar product 124 nm radar reflectivity at the lowest 0 5 deg scan Radar echoes are shown as color coded polygons that may be one of 15 colors If you need to see a scan over a wider area or at different elevations use the expanded Reflectivity menu instead to select a more specialized reflectivity product 66 Chapter Seven RADAR MENU Reflectivity Shows radar echoes in any of several formats Reflectivity is simply a measure of power returned to the radar in decibels dBZ 0 5 deg Shows reflectivity from scan elevation 1 tilted 0 5 deg from the ground This is exactly the same as base reflectivity shown in the radar main menu so you should not have to select this item 1 5 deg Shows reflectivity from scan elevation
15. Derived products 68 Climatology menu 71 Extract data 71 Graph 71 Hurricane tracks 72 Tornado tracks 72 GPS menu 75 Status 75 Start 75 Stop 75 Recenter map automatically 76 Settings 76 Other important information 76 Window menu 77 Add remove toolbars 77 Remove last product 77 Help menu 79 Register 79 Preferences 81 General tab 81 Meteorological tab 82 Maps tab 84 Station plots tab 86 Analysis tab 87 Styles tab 89 Miscellaneous 1 tab 91 Miscellaneous 2 tab 92 Annotations tab 92 APPENDIX 93 Printing 95 Importing radar graphics 97 Surface plot configuration 101 Color gradient fills 105 Points 107 Map attribute file structure 109 Field and product codes 111 GRIB data 115 Grid definition file 115 Fixing GRIB problems 115 Sources 117 New NWS GRIB filename convention 117 Old NWS GRIB filename convention 118 Documentation 119 Scheduler scripting 121 Scripting basics 121 Valid script commands 122 Valid product types 127 Sample scripts 128 Analysis scripting 129 Scripting locations 129 Command sentences 129 Examples 130 Summary of commands 131 Analysis theory 137 General description 137 Processing functions 138 Objective analysis functions 139 Numerical operators 142 References 144 Tabular weather data 145 Start sequence 145 Parameter list 145 Sample listing 14
16. LLLLLLLULLULUULVLLL4A Generate basemap The Generate Basemap panel is used to generate all workcharts from scratch This is the primary way that new maps for new workchart areas can be created The only alternate way to create such maps is to right click on a map and choose Recenter map the workchart will be adjusted to the new center Digital Atmosphere offers many different options described below to provide the exact map position and scaling factors desired Projection For standard vector geography drawn by Digital Atmosphere choose Orthographic The chart will be drawn according to the color style that you select below in Color Style To select raster graphics only for Profes sional Version users choose one of the raster charts listed For more information about raster graphics see About raster graphics below Latitude longitude Sets the center point of the chart to be drawn Scale Sets the width of the map in nautical miles Image width height Sets the image width and height of the map to be drawn in pixels A good value for most purposes is a width of 900 and height of 600 The image width and height controls are a powerful feature for presenting a depiction of a very large area or for publication purposes Scrollbars will appear on very large maps to help you navigate around them It is Chapter Four MAP MENU 29 recommended that you do not use image sizes greater than 3000 to 5000 pixels as this
17. Preferences gt Analysis HILO Plots H or L above data at gridpoint maximum minimum HIID Plots H LOWD Plots L MXMN Plots H minimum MAXD Plots above data above data or L above at gridpoint maximum at gridpoint minimum data at gridpoint maximum x above data at gridpoint maximum MIND Plots DVCV Plots minimum DVVD Plots CVVD Plots PLMN Plots minimum PLLD Plots m FoR above data or L above above data above data or L above above data at gridpoint minimum data at gridpoint maximum at gridpoint maximum at gridpoint minimum data at gridpoint maximum at gridpoint maximum 136 Appendix ANALYSIS SCRIPTING MNND Plots L above data at gridpoint minimum OVER Overlay basemap translucently good for fills CINT number Contour interval must be an nonzero positive number GRTN number Contours or fills greater than this number LSTN number Contours or fills less than this number EQUA number Plot a contour equal to this number LINE number Set line width must be nonzero positive integer FILL Fill using fill color SOLD Plot contours as solid line DASH Plot contours as dashes DOTS Plot contours as dots DADO Plot contours as dash dot DADD Plot contours as dash dot dot FILL Perform a floodfill FILS number Set fillstyle to one of the following must appear to right of FILL command 0 Solid default 1 Cross 2 Diagonal cross 3 Diagonal 1 4 Diagonal 2 5 Horizontal s
18. QFE not the sea level pressure unless you re re Chapter Three FILE MENU 25 ally at sea level You can find your actual pressure by simply calculat ing Station Pressure mb and entering your altimeter setting pressure in inches as provided in public weather reports and your elevation in feet An example In Denver Colorado your elevation is 5300 ft and the pressure is 29 96 inches This yields a station pressure or actual pres sure of 834 8 mb You can then use this value in calculations which ask for actual pressure Recompile tables This option is used to recompile station index listings from scratch Most users don t need to use this command since compiled tables are already provided with Digital Atmosphere It is used only when you have made editing changes to the station listings in digatmos stn and you want these changes to be enabled To modify digatmos stn you ll need a standard text editor such as MS DOS EDIT or Notepad Always be absolutely sure that you save the file as a ASCII text file or you will corrupt your installed copy When you have finished your changes you can use File gt Recompile Tables at any time to regenerate the internal listings It takes about about 1 to 5 minutes depending on your computer speed Once the procedure is finished Digital Atmosphere will make use of the new changes You may use Recompile Tables as many times as you wish RUUUUUUULUUUU RUL
19. Sons and Williams R T 1979 Numerical Prediction and Dynamic Meteorology John Wiley amp Sons Koch S E DesJardins M and Kocin P J 1983 An Interactive Barnes Objective Map Analysis Scheme for Use with Satellite and Conven tional Data Journal of Climate and Applied Meteorology 22 1487 1503 Little C D and Phillips G L 1982 A Method of Analyzing Height and Vorticity Fields using AFOS NOAA Southern Region Computer Programs and Problems NWS SRCP No 6 15 pp 147 APPENDIX Tabular weather data Digital Atmosphere is capable of importing observations from a comma de limited database listing This is excellent for weather observations exported out of a database or a spreadsheet It is also suitable for Australian AXF weather data If recognized as shown below the data will be imported and available for viewing as long as it is imported as usual from the data directory or from a specified file The rules for this data are Comma delimited data only Each line must correspond to one observation No extraneous commas are permitted even within quote marks The observation must contain the station s latitude and longitude To take advantage of this capability you need to open the DIGATMOS FMT file with a text editor and define the start sequence and the parameters that apply to that type of data Start sequence You define the start sequence by placing a start sequence between brac
20. Technologies and can be given only in accordance with our Furthermore the key number can be computed only if the serial number is provided The se rial number is unique to each computer and we can t predict what it will be If you don t supply it there will be a delay because we will have to ask you for it For most users the unlocking procedure only needs to be done once However if your company or organization specifically needs a pre un locked version of Digital Atmosphere without the serial key procedure we offer Digital Atmosphere 2000 Professional Version It is supplied on CD ROM Click the registration guidelines link above for more info If you have any questions please E mail the address shown at our con tact page at http www weathergraphics com contact htm or call us at toll free 800 840 6280 Thanks 80 About Displays basic information about Digital Atmosphere including the copyright notice and the version number 81 CHAPTER 12 Preferences Here s where you set your preferences for how the program will operate With that in mind take note of the following Any changes you make are used only for the duration of the program s ex ecution unless you place a check mark at the bottom of the page in the box named Save as default settings which will change them permanently Technically inclined users will note that the registry that is affected is HKEY_ CURRENT_USER Software Digital Atmosp
21. and may occur with other applications that make extensive use of the PCL driver 99 APPENDIX Importing radar graphics Here is a quick tutorial on how to add a radar site using South Africa as an example We Googled south africa radar and found a radar image page at http metsys weathersa co za We go to the page for Durban and see that there is an image Right clicking on the image we see that the radar image is stored in http metsys weathersa co za radar_image DN gif which is good as loopers and non fixed filenames can be considerably more complicated to deal with Now we need to get the latitude and longitude of this site It s not anywhere on the page however the website has a handy radar informa tion page at http metsys weathersa co za nwrn htm This shows Durban at 30 01S 30 93E Make a note of that Now we need to import the radar image into a graphics program we use PaintShop Pro In your browser right click on the image and choose Copy Image Then paste it in your software In another window open Notepad and then open your digatmos rdy file in the Digital Atmosphere directory Start a new line at the top of the data block anywhere in the list is fine but entering new items at the top we can see the column headers more conveniently In your graphics program position the cursor on the very center of the radar site and read the X Y coordinates wherever your graphics program displays it This shows a c
22. appear next to the menu option and click it again to disable it You will need to disable this function if you want to see bound box coordinates paths and path information generated by dragging the mouse on a map Information Displays detailed information about the map currently shown Included is the map width and height in both pixels and nautical miles the center latitude longitude of the map and the corner latitude longitude points All negative latitudes indicate the southern hemisphere and all negative longitudes indicate the western hemisphere fnformaton i Map width x height 5 2100 x 1600 pixels 2430 6 x 1835 3 nm Projection Orthographic Coordinates lat long Center 39 000 97 600 Top left 50 496 130 571 Top right 50 496 64 629 Bottom left 21 198 119 397 Bottom right 21 198 75 803 36 Chapter Four MAP MENU Set comment Sets an annotation that will be prefixed to the legend of a workchart when data or contours are drawn You can enter any information you want A typical purpose is for specifying exact dates Make topography Renders a topographic representation terrain features of the Earth on your map projection After the topography is drawn Digital Atmosphere then re overlays the basic geography data The topography draw opera tion may take a few minutes on slower computers 115 j AN Example of topography rendering for United States Import pla
23. as quality control scripting climatol ogy and loading saving of maps When you register you will receive a key number that you enter into Digital Atmosphere This prevents it from expiring or if the program has already expired it restores full functionality indefinitely We hope that our low price and our commitment to continued development work is an incentive to register We ve served weather enthusiasts for 14 years with affordable prices and highly accessible support rather than inflat ed markups and shoddy service which is common in the software industry If you send us an E mail you ll always get an E mail reply from us usually within 24 to 48 hours sometimes longer but a reply will come There s also a support forum at lt http www weathergraphics com forum gt Your registration is greatly appreciated RIGHTS There are no restrictions no licenses and no royalties on the use of maps produced by Digital Atmosphere They are considered to be your creations PRICING AND ORDERING Please visit lt www weathergraphics com gt for up to date information plus pricing and ordering methods Please be aware that you cannot reach us at our pre 2004 addresses sales weathergraphics com support weathergraphics com tim weathergraphics com etc We had to deactivate these addresses due to excessive incoming spam Please make use of our new address visit our Contact page at the website above Always check that pag
24. at each station plot when it is reporting valid wind data If un checked no wind barb is plotted on any report E Filter ASOS reports If checked Digital Atmosphere will plot hu man observations first with automated ASOS AMOS automated synoptic etc as last priority If unchecked no priority is assigned to any observation E Smart visibility plot If checked Digital Atmosphere will omit plot ting surface visibility when no significant weather is occurring If unchecked surface visibility is always plotted E Plot missing as M Missing values will be plotted as M E Color code IFR MVFER plots If checked when stations are reporting IFR conditions visibility less than 3 miles and or ceiling less than 1000 ft the OKTAS sky cover plot symbol is colored red when MVER conditions visibility less than 5 miles and or ceiling less than 3000 ft the OKTAS sky cover plot symbol is colored blue If un checked the standard draw color is used to paint the sky cover plot symbol Chapter Twelve PREFERENCES 87 E Use km when above 5000 m For visibilities that exceed 5 km 5000 m they will be plotted as km This is only effective if a surface plot block is VIS M Upper plot model These settings only apply when the active level is an upper level and plots are produced using Data gt Plot E Plot wind barb If checked Digital Atmosphere will plot a wind barb at each station plot when it is reporting valid wind da
25. be compressed according to the settings you specify here JPEG is a lossy compression scheme which means that higher compression values result in degradation of the image As the user you select the tradeoff that you think is most acceptable For a typical 640 x 480 image a setting of 0 loose will result in a high quality image with a filesize of 225K A setting of 100 tight will result in a very coarse image with a filesize of 11K Graticule type Digital Atmosphere can overlay a latitude longitude grid and here you can control how it will be displayed You will see the lat long grids only if the lat long grids setting in the map element table is checked and only when you re generate a new map Note that the grid interval is controlled by the grid interval setting and the color is controlled by the grid color listed in the map element settings color table E Line Plots latitude longitude as a series of lines E Mixed Same as line above but also adds dots for every integer degree of latitude and longitude The size and interval of the dots is fixed and cannot be controlled E Cross Plots a cross at each latitude longitude intersection E Dash Plots latitude longitude as a series of dashed lines E Dotted Plots latitude longitude as a series of dotted lines Graticule interval If a latitude longitude map is plotted this value controls what interval will be used in degrees to plot the grid A v
26. choosing a radar product will cause historical data to be accessed via the Internet This is slightly slow because the data directory will have to be analyzed to find the closest matching file time Password security has been introduced on scripting and internet re source URLs This allows you to devise your scripts so that they can be traded without compromising login information and so that they execute onscreen without being insecure They can be used for not only passwords but account names server names and so forth Your list of sensitive data must be maintained in DIGATMOS PWD On each line write token value where token is a name created by you and value is the actual value to be substituted When token your token word surrounded by double percent signs is found in a URL it is replaced with the equivalent value that you defined Digital Atmosphere will display the token marker so don t name tokens with sensitive information 164 Appendix VERSION CHANGE SUMMARIES VERSION Equinox 1 00 January 1 2007 Help files converted from WinHelp to CHM to ensure compatibility with Vista This removes dependencies on WinhIp32 exe 12 22 06 Fixed analysis labels to provide correct centering of individual labels and correct coloring 12 27 06 Fixed problem with Canadian radar data import Canada made some changes sometime in November 2006 This required some structural changes and a small change to the digatmos rdy file Pa
27. computer The exact font is obtained from the Preferences gt Styles setting tied to the workchart in use and may be modified to use a wide variety of font names and sizes 20 Chapter Three FILE MENU NCEP FONTS 01234567594 ABCUEPGHI JIKFLMMOPGRS TUE MI PTARAPRGGG f Ss 0125456789 ABCDEFGHIJKLINOP QL 2S 56 7a 0125456789 ABCDEF EL ODE OPIOS TK ekp Boon ODOGO9GGO8 g OOBOOAGARO as A a a a i ee S AAO y EnB f Mw E Geta N g lt gt j L A aE DIGITAL ATMOSPHERE NATIVE FONTS Alphanumeric characters use any Window Truetype font oo0009039090 090101000 8 1008E K ATS H VNINA O BAAD 4B Law ce aKen gt gt 2 2z Mos E OSEE eM EON 1143A DN ASANS s js sls t GSS S SIS gt h bats pawan xk FA TSO A A l Sr ee VRERERERER RG OG B Chapter Three FILE MENU 21 NCEP NMC Raster This is a special set of fonts that we extracted from NCEP weather software source code This font dates back to at least 1968 and can give a more professional look to certain charts About NCEP fonts The NCEP raster fonts called raster because they are not scalable like most Windows fonts are stored in several key files as described below They were used on NMC National Meteorological Center charts from the 1960s and are still in use today in certain National Center for Envi ronmental Prediction products They are stored in BMP format so users may edit them as needed Thes
28. down load see illustration from a product list Once you press Retrieve the chosen products will be downloaded and stored in your data directory Then you can use File Import Directory to see the results Data Retrieval Window xi 2 resources selected METAR from COD Us oniy Peel METAR from NWS US only Sometimes delayed METAR from Albany worldwide METAR for Kansas Tribune METAR from Texas Tech Texas only _ METAR from AustralianWeatherNews Australia echoes Add site Current time tokens Y jor m fos 25 H 22 N fs File Idle URL Idle Status Idle Progress Idle Since Internet sites sometimes change you can fully edit the list of prod ucts and data directly from this dialog box by highlighting the item you wish to change and clicking the Edit Site button or the Delete Site button 44 Chapter Five DATA MENU You can also add a new site by clicking the Add Site button You will then be prompted to enter the site name and URL for the data Time tokens Many sites especially for surface and upper air data have a filename that is dependent on the Greenwich Mean time of the observation To support this Digital Atmosphere lets you insert time tokens into a filename For example if you entered a product that had a URL address of http www weatherdata com Hdata txt Digital Atmosphere would automatically substitute the current UTC GMT hour in place of the
29. for managing large scripts Example SET 1 500 Sets keyword 1 to 500 PRODUCT 1 HGT 1 indicates 500 so here 500 mb heights are plot ted PRODUCT 1 TMP 1 indicates 500 so here 500 mb temperatures are plotted TIMERON Enables the script timer It will adhere to the current timer script sched ule 128 Appendix SCHEDULER SCRIPTING TIMEROFF Turns off the script timer PRINT Prints the map to the default printer using default settings SLEEP seconds Causes Digital Atmosphere to pause for the specified number of seconds An hourglass cursor will be displayed during this time SPAWN filename Executes an executable file or MS DOS batch file specified by filename must be a fully qualified filename with correct path e g c utilities myprogram exe MINIMIZE The Digital Atmosphere application window is minimized MAXIMIZE The Digital Atmosphere application window is maximized NORMAL The Digital Atmosphere application window is neither minimized nor maximized QUIT Quits the program MAPMAKING COMMANDS MAKE lat long zoom width height Makes a map using the given coordinates Lat is negative in the south ern hemisphere Long is negative in the western hemisphere Zoom is a value equal to 3964 x where x is the width of the map in statute miles Width and height are the map sizes in pixels TOPO Makes a topographic underlay on the map takes some time POINT Plots poi
30. k 1 n j exp w S k 1 n w where w 4 7 a At the completion of the above first guess calculations a difference pass is executed to compare the error of each actual data value f against its interpolated predicted value p within the objectively analyzed field The value i and j will refer to the fractional coordinate 0 1 of the observa tion within its surrounding objective analysis grid box of x x 1 and y a The calculations are done as follows orrs Jey r WU aig ago Tega t wie I fe t a yt x 1 a hott xti D 4 The error of each data value f against its predicted value p is deter mined through simple subtraction e f Px Using this error information a final pass is made which uses the above difference to correct the objective analysis field Again d is the distance between gridpoint f and observation point d in units of a Gamma g 0 1 usually 0 3 is obtained from the Analysis settings panel Using the weighting coefficient w an error value for each gridpoint z can be calculated as follows Z S k 1 n e exp w S k 1 n w where w d g Finally the error field is added to the first guess field to generate a cor rected field yielding a completed objective analysis Jo ale 7 oi Cressman analysis The Cressman objective analysis scheme Cressman 1959 is known as the successive correction method It achieves its result by forcin
31. menu option on how to add radars using the example of Durban South Africa This will be of considerable interest to international users Started preliminary work on importing GRIB2 data This module does not work and will not plot however the file will be handled with probably no errors Muted menu colors slightly to reduce blue and red saturation VERSION Equinox 1 04 January 7 2007 Preferences gt Annotations gt H and L characters now plot correctly The software was defaulting to H and L rather than using the characters shown here Removed possible error in installer related to tutorial directory This was returning a harmless error Incorrectly plotted coordinates when using older Digital Atmosphere charts from early Fusion and before has been fixed by adding sanity checks to the load function for dmf map data If the rotation value is out of bounds lt 360 or gt 360 deg which may be the case in earlier versions where the rotation value was not specified it will set it to zero and correct the source file permanently fixing the problem for that map Diagnosed slight positioning errors in contour labels and highs lows and fixed them VERSION Equinox 1 03 January 6 2007 METAR visibility values are now correctly ingested Fixed script LOAD command which was only loading in the image and not loading the background map and resizing the window Eliminated redundant labels in the chart
32. of Digital Atmosphere at all times Settings In this panel you set the baud rate data bits parity and stop bits Obtain these from the setup menu in your GPS It is recommended you use 4800 baud 8 data bits N parity none and 1 stop bit The setting will be remembered the next time you start Digital Atmosphere Other important information Please be aware that the mouse cursor will act erratically if the GPS is connected and running while Microsoft Windows is loading This is an extremely common problem in Windows due to deficiencies in the Plug and Play drivers and has been exhaustively documented by GPS users Try one of the most common fixes used by GPS users Temporary Leave the GPS unplugged whenever Microsoft Windows is loading Permanent Go to Control Panel gt System gt Hardware gt Device Manag er gt Mouse amp Pointing Devices and click on Microsoft Serial Ball Point then choose Actions and Disable If this does not work you can try open ing the device manager after an erroneous startup using the keyboard find which mouse driver is being used and disable that Find other suggestions at http groups google com groups q sci geo satellite nav Most GPS units are built with antiquated serial ports thus the support in Digital Atmosphere for this protocol If your computer does not have a serial port you may buy a USB Serial Adapter which brings in serial data through your USB port Belkin is one of t
33. operation When Digital Atmosphere first starts it reports the version number the Windows version and the amount of virtual memory available and in use The box periodically clears itself to conserve memory To clipboard Copies the contents of the Status Box to the clip board Show memory use If enabled Digital Atmosphere will report the available memory after each user interaction This is useful for tracking rare occurrences of memory leaks which in Windows 2000 and XP will manifest itself in the form of degraded performance over time and increased hard disk access Generally this Chapter Two DISPLAY COMPONENTS 13 number will fluctuate but if there is an overall downward trend this may indicate a problem Digital Atmosphere consults the system statis tics through GlobalMemoryStatus WinAPI calls using the formula M dwTotalPhys dwAvailPhys Workchart 125 _ 196 _ 150 29 236 7 27 _ 197 Uia 1380 a 69 3868 100 8191 39 23 12 N 100 49 08 W Weatherwise style Observations 3266 total 617 in domain 129 plotted The workchart is the large graphical space that is used to display maps plots and contours There can only be one workchart open at any one time You may resize the map by dragging the borders with the mouse Digi tal Atmosphere will remember the map dimensions even if the program is exited and restarted Popup menus Digital Atmosphere allows you to issue s
34. see a bounding box and within that a great circle path see the illustration Also in the status bar at the bottom of the screen you will see path data appear When you let go of the cursor the bounding box and great circle path disappear but the latest path data remains on the status bar Bounding box This defines a rectangular screen region that is used for certain operations within Digital Atmosphere most notably quality con trol File gt Quality Control Chapter Two DISPLAY COMPONENTS 15 Great circle path Within the bounding box you will see a diagonal line that connects the two corners of the bounding box your start and end location It may have a small or great amount of curvature This is a great circle path literally the shortest path between the start location and the mouse loca tion It represents the path that would occur if you found two points on a globe and connected them with a string Airplanes always try to adhere to great circle paths when routes and weather permit thus you can use this feature to find the most likely route for long distance flights A great circle path may have a curved look at wide map views especially toward the edges of the screen due to inherent distortions in the map projection Only on the gnomic projection would a great circle path be a perfectly straight line Digital Atmosphere does not support gnomic projections Path data Shows the coordinates of the start and end points f
35. snow with or without ice covering half to less than entire ground 13 Even layer of compact or wet snow covering ground completely 14 Uneven layer of compact or wet snow covering ground completely 15 Loose dry snow covering less than half of ground 16 Loose dry snow covering at least half of ground but ground not com pletely covered 17 Even layer of loose dry snow covering ground completely 18 Uneven layer of loose dry snow covering ground completely 19 Snow covering ground completely deep drifts Interpreting synoptic cloud amount codes CLDAMT This category is defined as Nh the amount of all the low cloud present or if no low cloud is present the amount of all the middle clouds present The figure is always in oktas eighths 9 is reserved for sky obscured by fog and or other meteorological phenomena and is reserved for cloud cover being indiscernable for reasons other than fog or other meteorological phenomena or observation is not made Appendix SURFACE PLOT CONFIGURATION 105 Interpreting synoptic cloud height codes CLDHGT This category is defined as h which is reserved for the height of the surface of the base of the lowest cloud seen They are as follows below If the total sky cover is greater than 4 8ths this figure is also transposed into the CIG slot where they are plotted as L low cloud followed by a loose transla tion of the table below in hundreds of feet This L differentiates i
36. so users are free to swap out the existing tables with fresh ones The files are located in the hurr directory Tornado tracks Digital Atmosphere is equipped with a database of United States torna does that occurred between 1950 and 2002 These may be plotted on any weather chart for reference purposes It is important to note that due to limitations in available data the database carries only the start and end location of a tornado track and not the intermediate points This means that tracks will tend to be more accurate for short slow moving torna does and much less accurate for long tracked fast moving tornadoes This is a limitation in the way that tornado climatology is compiled by Chapter Eight CLIMATOLOGY MENU 13 the National Weather Service and neither Digital Atmosphere nor its authors have any control over this Year Choose a range of years to display only data during these periods To display data for only one year set both blanks to the same value Choose all if you want all years in the database to be displayed Month Choose a range of months to display only data during these periods To display data for only one month set both blanks to the same value Choose all if you want all months in the database to be displayed Day Choose a range of days to display only data during these periods To display data for only one day set both blanks to the same value Choose all if you want all days in t
37. them in detail at this time 8 Chapter Two DISPLAY COMPONENTS Speed buttons i eS 7 The speed buttons are provided as a convenient way of accessing fre quently used main menu commands You can find the meaning of each one by simply resting the cursor on a button a popup hint will appear Each button corresponds to a main menu command summarized as fol lows going left to right eB Import a file Accomplishes the same thing as File gt Import file la Import a directory File gt Import directory a Print File gt Print A Preferences File gt Preferences Ga Internet retrieval Internet gt Retrieve Data O Load a map Map gt Load Map ge Erase workchart Map gt Erase Map da Data plot Data gt Data Plots E Quality control File gt Quality Control e Calculator File gt Calculator P2 Zoom in Zooms in on the map not for raster basemaps so Zoom out Zoom out from the map not for raster basemaps amp Generate basemap Map gt Generate map Chapter Two DISPLAY COMPONENTS 9 SLP B SLP Performs a sea level pressure analysis kE F Performs a temperature analysis in degrees Fahrenheit Ka C Performs a temperature analysis in degrees Celsius Toolbox The toolbox is designed to hold controls and features which are not suited to the main menu and for which the user needs rapid access There are three main panels the control panel the fronts panel and the sc
38. this handy it is recommended so that you can review observa tions for vital clues such as observer remarks as well as look through any forecast data you might have captured The file that is shown is the internally saved clean data file produced by the most recent File Import command The original raw data file is not 24 Chapter Three FILE MENU referenced and does not have to be present If you don t like this inter face you can view the same data file using any text editor and setting it to examine DATA USR in your Digital Atmosphere directory The View Raw Data panel also has a Find function that lets you search for stations and keywords in the file Print Sends the currently selected workchart to the printer See the Appendix chapter on Printing Print setup Sets the default printer behavior for this Digital Atmosphere session See the Appendix chapter on Printing Calculator Do you need to find a wind chill value A mixing ratio A theta E No problem Digital Atmosphere s meteorological calculator lets you plug in values and find a result Simply choose the conversion you want at the top enter the values in the center panel then press Calculate Peles Mixing Ratio Temperature s deg C or K Actual Pressure 976 mb Mixing Ratio 196 gkg Calculate Help Note about actual pressure When an entry box asks you for Actual Pressure this indicates the actual pressure of the parcel
39. title stack to prevent multiple display of the exact same chart title Appendix VERSION CHANGE SUMMARIES 163 Fixed problem with GRN or TEMPO in METAR being interpreted as GR and PO weather types Improper time token entries in Internet Retrieve using one instead of two digits will be automatically detected and corrected View Last Radar Product fixed so as to plot the last radar product A Window gt Replot Last Product command has been added to replot any last product Added Window gt Allow Digital Atmosphere to run in background command which prevents Digital Atmosphere from popping up such as during scripting operations and regaining focus Right now this only suppresses the plotting radar message if you see Digital Atmosphere pop up at other times please send detailed information Tutorial directory and sample txt file added to build VERSION Equinox 1 02 January 2 2007 Emergency patch as Internet gt Retrieve was nonfunctional due to prob lem in URL preprocessor VERSION Equinox 1 01 January 2 2007 When all workcharts are closed and then new ones are created there is now proper handling of the workchart and its background map The user no longer gets an empty frame Added ability to auto retrieve historical past 1 2 weeks radar images based on date time selection from Radar gt Set Date Time and pres ence of an archival source in the digatmos rad resource file If these are selected then
40. velocity from scan elevation 4 tilted 3 4 deg from the ground Spectrum width Spectrum width is a measure of the variance in velocity within each bin It is actually generated from a pulse pair algorithm rather than being computed directly from velocity data The product is generated using 7 levels with a maximum possible width of 20 kt Anything beyond 20 kt is truncated by the radar unit The spectrum width product it is the basis for the WSR 88D turbulence products The application of the product to severe thunderstorm fore casting is not known but it may be a secondary indicator of small torna does landspouts and gustnadoes 32 nm Uses the close range radius of 32 nm at 0 13 nm resolution 124 nm Uses the standard radius of 124 nm at 0 54 nm resolution Derived products A number of derived products are generated from the base products of reflectivity velocity and spectrum width Echo tops ET This displays the highest altitude at which a radar echo exceeds 18 5 dBZ It is computed to the nearest 5 000 ft up to a maximum height of 70 000 ft The standard coverage radius is 124 nm with a resolution of 2 2 nm Vertically integrated liquid VIL Sums the reflectivities above a bin location to provide a measure of the total water load above a given location in kilograms per square meter It has a direct correlation to severe weather hail and flood potential and is most useful in assessing in an extremely short
41. 0 DASH COLOR 200 0 0 SDIF 1 2 STOR 2 HGHT H000 STOR 1 HGHT H500 Explanation Take the 500 mb height field Store it in slot 1 Take the 1000 mb height field Store it in slot 2 Compute a difference between field 1 Appendix ANALYSIS SCRIPTING 133 and2 Nowsetthepencolorto200 0 0 lightred i e red 200 green 0 blue 0 Set lines to dashed and set a contour interval of60 Nowcontour there sult This produces the1000 500 mb thickness For other examples please open the DIGATMOS MNU file and study the examples provided They drive the Analysis dropdown menu Summary of commands SETUP HSFC HOOO H925 H850 H700 H500 H400 H300 H250 H200 H150 H100 Set level to surface Set level to 1000 mb Set level to 925 mb Set level to 850 mb Set level to 700 mb Set level to 500 mb Set level to 400 mb Set level to 300 mb Set level to 250 mb Set level to 200 mb Set level to 150 mb Set level to 100 mb Analysis method if not specified setting in Preferences gt Analysis will be used ANLN ANLW ANLC ANLB BASE TEMP THTA DWPT RELH BULB MIXR HIDX HGHT GHGT THTE K PTEN WCHL HIDX Sets analysis method to Nearest Neighbor Sets analysis method to Weighted Sets analysis method to Cressman Sets analysis method to Barnes FIELDS Temperature deg C Theta or potential temperature deg K Dewpoint deg C Relative humidity Wet bulb temperature deg C Mixing ratio g kg Heat index deg F Geopotential
42. 2 tilted 1 5 deg from the ground 2 4 deg Shows reflectivity from scan elevation 3 tilted 2 4 deg from the ground 3 4 deg Shows reflectivity from scan elevation 4 tilted 3 4 deg from the ground Extended 248 nm 0 5 deg This is similar to the 0 5 deg reflectivity scan but shows it over a wider area 248 nm This comes at the cost of degraded resolution 1 1 nm instead of 0 54 nm Composite Composite reflectivity blends all available elevations showing the highest reflectivity in all elevations above a given point on Earth This is useful for showing all echoes returned by the radar regardless of scan elevation However this masks important features useful for se vere weather forecasting such as hook echoes and reflectivity gradients which are seen only on base slices Composite reflectivity can give false impressions of precipitation at the surface from suspended precipitation as in storm anvils Extended 248 nm composite This is similar to the composite product but reaches over a wider area 248 nm instead of 124 nm Chapter Seven RADAR MENU 67 Velocity Shows radial velocity to and from the radar site in any of several for mats It is expressed in knots Positive velocity is always motion away from the radar while negative velocity is always motion toward the ra dar As a mnemonic it is useful to link positive typical values to that of energy being transmitted from the radar typical radar e
43. 3 CONT CINT 2 COLOR 200 0 0 DASH DEGF TX24 Min temperature 24 h deg F 3 CONT CINT 2 COLOR 200 0 0 DASH DEGF TN24 Moisture Dewpoint deg F CONT CINT 5 COLOR 0 150 0 DEGF DWPT Relative Humidity CONT CINT 5 COLOR 50 150 0 RELH Mixing Ratio g kg CONT CINT 1 COLOR 0 100 0 MIXR Theta e deg K CONT CINT 2 COLOR 0 50 150 THTE Heat Index deg F CONT CINT 5 COLOR 0 0 50 HIDX Humidex deg C CONT CINT 5 COLOR 0 0 50 HUMX Wet bulb temperature deg C CONT CINT 5 COLOR 0 50 50 BULB Colored dewpoint deg F CONT EQUA 60 COLOR 0 0 0 LINE 3 CONT GRTN 60 CINT 2 COLOR 0 0 200 LINE 1 CONT LSTN 60 CINT 2 COLOR 200 0 0 LINE 1 DEGF DWPT Pressure Sea level pressure mb 1 HILO CONT CINT 5 LINE 5 SLPR Pressure isentropic CONT DATA CINT 10 PRES Pressure tendency CONT CINT 2 PTEN Altimeter setting in Hg HILO CONT CINT 0 05 ALST 500 mb height m cont cint 60 color 80 80 140 hght h500 Height m CONT HGHT Balanced height field m CONT LINE 3 CINT 60 COLOR 0 0 0 GHGT 1000 500 mb thickness m CONT CINT 60 DASH COLOR 200 0 0 SDIF 1 2 STOR 2 HGHT H000 STOR 1 HGHT H500 Wind Wind speed barbs kt BKNT COLOR 0 0 200 WIND Wind speed vectors VECT COLOR 0 0 200 WIND Streamlines STRM WIND Wind speed kt CONT COLOR 0 200 0 VKNT WSPD Wind shading upper level kt OVER FILL COLOR 200 100 200 FILS 0 GRTN 110 VKNT WSPD FILL COLOR 200 100 100 FILS 0 GRTN 90 VKNT WSPD FILL COL OR 200 200 100 FILS 0 GRTN 70 VKNT WSPD
44. 30025 50559 etc Weather watches Also called SELS watches watch boxes or even WWUS9 KMKC This is an English bulletin produced by forecasters at the Storm Prediction Cen ter formerly NSSFC the National Severe Storms Forecast Center WWUS9 KMKC 141239 SEL7 MKC WW 141239 KSZ000 142000 BULLETIN IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 77 NATIONAL WEATHER SERVICE KANSAS CITY MO 639 AM CST THU MAR 14 1996 A THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PARTS OF EAST CENTRAL AND SOUTHEASTERN KANSAS EFFECTIVE THIS THURSDAY MORNING AND AFTERNOON UNTIL 200 PM CST LARGE HAIL DANGEROUS LIGHTNING AND DAMAGING THUNDERSTORM WINDS ARE POSSIBLE IN THESE AREAS Appendix RAW DATA SAMPLES 159 THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 45 STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST OF EMPORIA KANSAS TO 45 MILES EAST OF CHANUTE KANSAS Convective outlook The convective outlook is a bulletin produced by forecasters at the Storm Prediction Center formerly NSSFC the National Severe Storms Fore cast Center and intended for use by other National Weather Service meteorologists Two are produced one for the today time frame Day 1 and another for the tomorrow time frame Day 2 It is one of the best sources of forecast information on the potential for severe thunder storms ACUS1 KMKC 141441 SWODY 1 MKC AC 141441 CONVECTIVE OUTLOOK
45. 3339 0510 182710 27009792 173109 24999491 TTPTTR1R2R3 GEG 894554 06000877354 12014928044 18000957342 24011957646 30000957544 36004938141 42003837138 48000614637 VVVLI 03407 02207 03104 02502 02502 01001 01501 00703 00007 161 APPENDIX Version change summaries VERSION Equinox 1 10a May 24 2007 Micropatch to fix corrupted handling of downloaded radar data data was downloaded into obs 001 obs 002 etc and program needed to find these in nids 001 nids 002 etc Added description element into version change message so users can decide whether a download is needed when a notification is re ceived VERSION Equinox 1 10 May 18 2007 Numerous fixes and repairs including fixes for handling of climatologi cal daily data from SYNOP reports VERSION Equinox 1 05 January 17 2007 A few new Mexican radars in the northwest provinces have been added to DIGATMOS RDY Not all radars are active as Mexico s radar network is not reliable Internet gt Retrieve shows how many items are selected Map gt Overlay gt Points now uses a more capable file format See the help under Map gt Add Point It allows the use of lines attributes that can be changed and shortcuts Map gt Overlay gt Points now prompts for a filename Editing is no lon ger done in the program as editing flow was unclear Contour labels are now plotted at the top of closed contours Removed digatmos ptt from pr
46. 45 COLD WK 3865 3763 3463 3164 2869 2673 2478 2384 COLD WK 66144 64142 62142 59142 53145 48149 45153 42156 40162 STNRY WK 55116 59117 62121 65129 67138 69144 69155 68167 68176 STNRY WK 6291 6395 64101 64110 63117 OCFNT WK 76114 77111 78104 7895 7786 7680 COLD WK 36102 34103 32104 31106 TROF 36101 35101 32100 30101 28102 26102 COLD WK 7680 7574 7168 6866 6565 6365 5969 5672 STNRY WK 37103 38104 40106 40109 41111 43114 44117 WARM WK 38101 3999 3897 3795 3791 TROF 48112 51112 55112 TROF 5294 5095 4896 4498 4199 TROF 5571 5270 4968 4767 NNNN Fleetcode Imports FLEETCODE format data It produces graphics like those shown below All fronts and isobars are plotted as spline curves and due to the limited resolution of the data they may not display optimally There is no way to alter how a spline plots except to change the scale of the work chart To the author s knowledge FLEETCODE data is produced only for Europe It comes in under the ASXX21 Family of Services header One source ready for use is provided in the default Internet tables Chapter Five DATA MENU 53 Sferics This option plots sferics lightning strike data from SFLOC data if it has been downloaded Currently this data is available only for the European region Using this information Digital Atmosphere will plot lightning strikes to the nearest half degree about 40 km resolution Europe imposes restrictions on the commercial use of lightning data
47. 6 Valid parameters 146 More on Australian AXF data 147 Exported analysis grids 149 Language support 151 About weather data 153 Raw data samples 155 Airways SAO data 155 SD RAREP radar reports 155 FD winds aloft data 155 Rawinsonde data 156 Weather watches 156 Convective outlook 157 Model output data 157 Version change summaries 159 DIGITAL ATMOSPHERE INTRODUCTION in 1992 and rewritten under Windows in 1996 encompasses thousands of hours of programming by one person and is the unique result of twenty years of forecasting experience working with various meteorological worksta tions and mainframes and many years of amateur observation activities and storm chasing This manual is designed to help you get up and running with this advanced but easy to use weather analysis program It will start out by taking you on a short overview of Digital Atmosphere Following that each menu com mand is explained in detail Finally there is an extensive appendix with possibly all the miscellaneous information you could ever want Tes for trying out Digital Atmosphere This software initially developed Whar s DIGITAL ATMOSPHERE It s a powerful weather prediction tool It s hands down the leading weather software program for Windows and is used by the National Weather Service the Air Force and Navy dozens of television stations and consulting firms and hundreds of amateurs and hobbyists Its powerful a
48. 6 2 MIS LAT 67 6 LON 60 6 DAT 1 10 Date DAT 12 6 Stn_num DAT 23 40 Name DAT 81 5 Precipitation_mm DAT 87 1 PP DAT 89 1 DC DAT 91 1 OF Television plots 50 Chapter Five DATA MENU Plots large font displays of temperatures The word television does not mean that they are for television use but rather that the temperatures are displayed in a format that looks a lot like that seen on TV Very important Before you can use this option successfully you will need to configure the DIGATMOS PLL file correctly with any text editor such as Windows Notepad DIGATMOS PLL is in your Digital Atmosphere directory The structure is as follows where the first column is the ICAO identifier for METAR data and the second column is the WMO station identifier for SYNOP data The third column is the name of the station city as it should ap pear on your weather map KORD 72530 Chicago KSEA 72793 Seattle KSFO 72494 San Francisco KLAX 72295 Los Angeles KBOI 72681 Boise KABQ 72365 Albuquerque The font used by this plot type is specified in the style definition for your workchart Warnings Plots warnings that were imported from the most recent data import ROLLA UULU U LUU UUUUU LLULLU U LUULU UUL UU LLULLU UUL UULL UULU UULU LUULU UULU UULU illite NOTICE This module has not been working since 2001 due to develop ment work on other parts of this software We will re enable it as soon as practical
49. 69 231 10 LEVEL 36 107 012 198 10 LEVEL 39 198 016 132 10 LEVEL 42 189 101 132 10 LEVEL 45 206 134 057 10 LEVEL 48 247 195 049 10 LEVEL 51 255 251 000 10 LEVEL 54 255 154 090 10 LEVEL 57 255 093 008 10 LEVEL 60 255 052 024 10 LEVEL 65 189 190 189 10 LEVEL 70 214 211 214 10 Note that extraneous zeroes have been prefixed to make numbers two or three digits This is optional and has been done here to make the file look neater We will also skip South Africa s 80 dBz since it matches the basemap color white and may give undesirable results Finally we need to hook up this table number 05 with the Durban radar entry above Put this number under CO to point it at the table We re done Now generate a map in Digital Atmosphere for Durban the ICAO is FADN and use a tight zoom level of about 300 or 400 nm Now use Radar gt Import Images and Clear All and then check Durban 102 Note that there are traces of radar range rings This cannot be avoided since it is an artifact on the original image The outer red radar range ring is pro vided by Digital Atmosphere to mark the maximum extent of radar informa tion and can be shut off by putting RANGERING 0 instead of RANGER ING 1 before the TABLE entries in digatmos rdy The palette can also be changed in this section to something more desirable APPENDIX 103 Surface plot configuration Table of valid data plot elements Units marked C or F or ft or m or
50. 98 ECMWF GLOBAL WAVE 128 98 ECMWF GLOBAL ATMOS 216 98 ECMWF LIMITED WAVE Now we need to find what field 129 is Googling for ecmwf grib 129 height since we suspect 129 is a height field we get a good link at http www cgd ucar edu cms eaton cf metadata ECMWF html This shows that 129 is indeed a geopotential height field Since everything in this ECMWF Grib Code list is useful we should ideally enter every thing but since ECMWF restricts most of its data it s smarter to make only a small number of changes as listed below in the FIELD block Note that we specify that these fields only apply to products from centre 98 ECMWF 1 98 Pa slp Pressure 2 98 Pa slp Pressure MSL 7 98 cm hgt Geopotential height 11 98 K tms Temperature 41 98 S vrt Vorticity absolute 43 98 S vrt Vorticity relative 129 98 cm hgt Geopotential height 138 98 S vrt Vorticity relative Appendix GRIB DATA 119 We entered cm under geopotential height so that isopleths will plot legibly It is also acceptable to use dm and m That s it Our model data will plot correctly now Sources The majority of GRIB output data is available from supercomputer mod els such as the ETA model output provided by the National Center for Environmental Prediction near Washington DC Sources of data include ftp 140 90 88 142 http weather noaa gov pub SL us008001 ST opn1 Choose the grl directories Within these t
51. ANT REPEAT CENTER LOCATED NEAR 17 3N 94 0W AT 06 0900Z AT 06 0600Z CENTER WAS LOCATED NEAR 17 5N 93 9W FORECAST VALID 06 1800Z 16 9N 94 1W INLAND DISSIPATING MAX WIND 20 KT GUSTS 25 KT FORECAST VALID 07 0600Z DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 17 3N 94 0W THIS IS THE LAST FORECAST ADVISORY ISSUED BY THE NATIONAL HURRICANE CENTER ON LARRY UNLESS REGENERATION OCCURS FORECASTER PASCH Troubleshoot data This interface shows at a glance which datasets are available from the most recent import operation If a dataset is shown as empty it cannot be plotted Note that some data may be shown which does not really exist due to wide variations in coding formats You should consult this to check on any problems before reporting a problem about data not plotting If no data is shown check your source the URL it came from if any and make sure the system clock settings are correct on your com puter since some products are time dependent 58 59 CHAPTER 6 Analysis menu The Analysis commands comprise a powerful tool which can display iso bars isotherms wind grids and much more All imported weather data is examined objectively analyzed filtered and smoothed and then displayed graphically Beginning with the Workstation series of Digital Atmosphere in 2004 users can now construct their own analysis fields and displays through a highly sophisticated scripting language Users can al
52. BELOW Pictogram of direction of ship movement Speed of ship movement kt Sea surface temperature C or F Type of temperature measurement device Period of ocean waves sec Height of ocean waves ft or m Instrument measured height of ocean waves ft or m Ocean wind wave period sec deg K 104 WINDHGT SWELL1DIR SWELL2DIR SWELL1PD SWELL1HGT SWELL2PD SWELL2HGT MINTEMP MAXTEMP GRNDSTATE Appendix SURFACE PLOT CONFIGURATION Ocean wind wave height ft or m Direction of primary ocean swells deg Direction of secondary ocean swells deg Primary ocean swell period sec Primary ocean swell height ft or m Secondary ocean swell period sec Secondary ocean swell height ft or m Minimum temperature C or F Maximum temperature C or F Ground state code see below Interpreting ground state codes GRNDSTATE The ground state codes are as follows 0 Surface of ground dry without cracks and no appreciable amount of dust or loose sand 1 Surface of ground moist 2 Surface of ground wet 3 Flooded 4 Surface of ground frozen 5 Glaze on ground 6 Loose dry dust or sand not covering ground completely 7 Thin cover of loose dry dust or sand covering ground completely 8 Moderate or thick cover of loose dry dust or sand covering ground completely 9 Extremely dry with cracks 10 Ground predominantly covered by ice 11 Compact or wet snow with or without ice covering less than half of ground 12 Compact or wet
53. EHA LAA GLD HLC SLN CNU SGF JBR MKL TUP LUL 35 SE HUM CONT 30 S CRP 25 S LRD GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 30 ENE ELO 50 NW EAU DBQ HUF LUK HTS TRI 65 S TYS ATL ABY AQQ CONT 40 SW DMN 50 WNW ONM GUP 60 ESE PGA U17 VEL 45 NNE CAG CYS SNY ANW JMS 70 NNE DVL MODELS INDICATE UPPER CLOSED LOW OVER NORTHERN BAJA WILL EVOLVE INTO A SHORT WAVE TROUGH AND ACCELERATE EASTWARD INTO THE SOUTHERN PLAINS SUNDAY SUNDAY NIGHT THIS IS IN RESPONSE TO VIGOROUS NORTHERN BRANCH SHORT WAVE TROUGH NOW OVER THE PACIFIC NORTHWEST AND PROGGED TO CONTINUE TO DIG INTO THE CENTRAL ROCKIES BEFORE SHIFTING EASTWARD INTO THE CENTRAL PLAINS AS THESE SYSTEMS INTERACT AND UPSTREAM SHORT WAVE DIGS ACROSS THE NORTHERN PACIFIC COAST INTO THE GREAT BASIN MODELS INDICATE EVOLUTION OF LONG WAVE Troubleshoot data This produces a panel that shows what types of data have been found in Digital Atmosphere You can use it to determine whether Digital Atmo sphere has correctly downloaded and imported various types of data 56 Chapter Five DATA MENU Troubleshoot data i 5 x This list shows what datasets have been imported into Digital Atmosphere All datasets are cleared out whenever a file import operation commences Only data that is recognized by Digital Atmosphere will be shown and used All other data is discarded You may use this panel to get more information about why a particular type of data did not plot Click on a fil
54. FILL COLOR 100 200 100 FILS 0 GRTN 50 VKNT WSPD Geostrophic wind barbs BARB GEOS SMTH GHGT Absolute vorticity MXMN CONT LINE 2 CINT 2 COLOR 250 50 50 138 Appendix ANALYSIS SCRIPTING SMLC 1 100000 STOR 1 AVRT WIND Relative vorticity MXMN CONT CINT 2 COLOR 250 50 50 SMLC 1 100000 STOR 1 RVRT WIND Abs vorticity of geos wind CONT CINT 2 DOTS COLOR 200 0 0 SMLC 1 100000 STOR 1 AVRT GEOS SMTH GHGT Divergence 10 6 s CONT MXMN CINT 5 SMTH SMLC 1 1000000 STOR 1 DVRG SMTH WIND Temperature advection CONT CINT 0 1 ADVT TEMP WIND Precipitation inches 1 hr CONT CINT 0 05 MMIN PCO1 2 hr CONT CINT 0 05 MMIN PCO2 3 hr CONT CINT 0 05 MMIN PCO3 6 hr CONT CINT 0 05 MMIN PCO6 9 hr CONT CINT 0 05 MMIN PCO9 12 hr CONT CINT 0 05 MMIN PC12 15 hr CONT CINT 0 05 MMIN PC15 18 hr CONT CINT 0 05 MMIN PC18 24 hr CONT CINT 1 PC24 139 APPENDIX Analysis theory This technical section is designed to document the numerical analysis meth ods used by the Weather Graphics Technologies software product Digital Atmosphere It is intended to provide a basis for academic and operational understanding of the algorithms used for Digital Atmosphere contouring and objective analysis General description Domain Currently the analysis domain is a floating fixed to the screen window gridpoint model fixed at a size of 30 x 30 in the x and y direction 900 points This scheme was chosen because the vast majority of objective analy
55. LU UULU LUUULUUULU UULU LUULU UULU bb UULU LLULL LUULU UU LUULU UULU UU LLULLU UULU LLULLU LULUKU UIU UULUUIIRRX N CAUTION SPECIAL NOTE Effective with Digital Atmosphere Original V2 2 released in 1998 a new station table format was being used which contains changes in columns and data fields Never try to import older DIGATMOS STN formats as you will corrupt your installed copy LL dedddddddddddddddddddddddddddddeddddddddddddddddddddddddeddeddddddddddddddd as UMMA A LLL iii Preferences See the special chapter PREFERENCES 26 Chapter Three FILE MENU Exit Exits Digital Atmosphere The background map will be saved and it will automatically appear the next time you run the program The last data set you imported will continue to be available 27 CHAPTER 4 Map menu These map commands are used for all mapping operations relating to Digital Atmosphere Erase map Erases the workchart Use this command whenever you want to erase weather data from the map and start with a clean map Load basemap Loads a workchart from your disk drive You will need a previously saved workchart which can be saved using the Save Map command Save basemap Saves the workchart for future access within Digital Atmosphere This also saves any markings annotations weather data and contours that are on the map already as a permanent part of the map so if you intend to load this map later without any weather data you ll ne
56. NU 33 Also use search engines like Google to search for GIS data for your area Look in government city transportation and planning web pages Some forward thinking cities such as Austin offer their data publically see ftp coageoid01 ci austin tx us GIS Data Regional coa_gis html for an example but extremely localized shapefiles such as these may be too small of a scale to be useful with weather data Also some local governments in the U S have withdrawn GIS data due to due to post 2001 paranoia or government entanglements with contractors and private interests H akta Copy markings onto basemap This function merges all information on the map including contours plots and annotations so that they all become part of the basemap itself This is useful only when you have overlaid county lines or highways or extra geographic information from shapefiles and you wish to retain the markings All of the markings are lost when a new basemap is regener ated so it may be desirable to save the new map for later use using Map gt Save 34 Chapter Four MAP MENU Copy chart to clipboard This is the easiest way of transferring a workchart to another software program When you choose this the workchart is placed in the Windows clipboard From there you can paste it into any of your favorite graphics programs Export chart This command is exactly identical to Save Map except that no map attr
57. REF AFOS NMCGPH940 VALID 141500Z 1512002 REF WW NUMBER 0077 VALID TIL 2000Z THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM PGO OKC 30 NNE P28 35 ESE SLN OJC JEF MVN EVV BWG BNA MEM PBF PGO GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM OXR FAT TPH ELY 15 NW PUC CAG LIC HLC FNB PIA FWA YNG DUJ DCA 25 W RIC RDU AND CBM TXK FSI 60 NNE AMA RTN 10 SE ABQ 30 SSW DMN Model output data These are numerical output bulletins from the National Center for Envi ronmental Prediction NCEP formerly known as NMC which describe forecast parameters at different locations around the country These bul letins are available on most weather databases For those who want the real thing from the supercomputers full fledged model output is ina binary format known as GRIB these files are huge hard to obtain and are not importable into Digital Atmosphere at this time 652 FOUS72 KWBC 201200 160 Appendix RAW DATA SAMPLES OUTPUT FROM ETA 12Z JAN 20 96 TTPTTR1R2R3 VVVLI PSDDFF HHT1T3T5 PSDDFF HHT1T3T5 SEA 928157 03005 131714 30989795 152312 25969490 06021947750 05304 021921 34009996 101416 29979693 12010957438 1802 992315 30019995 021809 32999795 18006957340 01501 992612 30019995 012208 30999895 24005977941 02601 012517 28019995 022516 29999794 30010967941 01201 042819 27019894 042513 27009894 36005856037 0202 102814 26019894 072607 27009794 42000794430 0906 152811 25019793 123009 26009693 4800078
58. The columns used are as follows Col Contents 1 2 Latitude of city in degrees 3 4 Latitude of city in minutes 5 N or S latitude sign 7 9 Longitude of city in degrees 10 11 Longitude of city in minutes 12 E or W longitude sign 14 33 Name of city as you want it to appear Chapter Four MAP MENU 39 The DIGATMOS CIT file contains some default cities that are formatted per the above specifications which you may find useful to refer to as a template when adding new cities Point Overlays a specified point on your map from a given file Files should have the name pls where is any chosen name In other words use the file extension pls This is not required but will help keep your filenames organized See the chapter on Point Overlays for informa tion on how to construct point files Aeronautical route You may display an aeronautical route using this panel Follow the format CC III or CC III CC III or CC TII CC III CC III where CC is the country designator FIPS 10 4 two letter country code with a solidus followed by III the identifier The identifier may be an airport VOR or waypoint The following will plot a route from Los Angeles to New York US LAX US JFK Add station reference The station reference control panel allows you to add markings on your map that show available weather stations You can use this to develop locator charts for your forecast desk and help find stations that are not reporting data o
59. This panel allows you to import and view GRIB data Click Import to choose a file to view Make sure either plot or contour are selected and choose Select Field to view the desired GRIB field Fronts tab View fronts Displays whatever frontal id dtl bulletin currently resides in the QUEUE FRT file This bulletin may be imported from a the Internet see using original sources of Isopleth data below or may be created by the user see create and making your own maps Gold Front below Warm Front Stationary Front Start new overlay Erases any drawings in progress or that may have been done earlier and starts a new overlay Occluded Front Enable drawing mode When enabled com mand inputs are taken from the mouse while on the workchart and lines or features are drawn Isopleth When pressed any line being drawn terminates and further drawing is begun using an isopleth a thin black line Cold front When pressed any line being drawn terminates and further drawing is begun using a cold front Warm front When pressed any line being drawn terminates and further drawing is begun using a warm front Stationary front When pressed any line being drawn terminates and further drawing is begun using a stationary front Occluded front When pressed any line being drawn terminates and further drawing is begun using an occluded front Chapter Two DISPLAY COMPONENTS Ti Trough When pressed any line b
60. To resolve this you need to identify the centre model and field causing the problem Go to File gt Preferences gt Misc 2 and enable Debug GRIB Data When this is enabled it causes full information to be displayed in 118 Appendix GRIB DATA the field selection panel rather than the simplified user friendly format For example we recently had display problems with ECMWF data and the field panel showed 72HR 500 MB ECMWF CREATED 29DEC06 1200Z When the debug mode was enabled we saw this TIME 1 72HR LEVEL 100 500 MB FIELD 129 CENTRE 98 ECMWF MODEL 128 CREATED 29DEC06 1200Z Thus it can be seen that Digital Atmosphere was unable to decode FIELD and MODEL and only the coded values are known 129 for field and 128 for model To determine the missing information we have to do some Googling For the model number we made the query ecmwf global grib 98 128 in Google The page http www ecmwf int products data operational_sys tem evolution evolution_2006 html tells us The new GRIB model identi fier for the atmospheric model will be 128 The model identifiers for the wave models will remain the same 116 for the global wave model and 216 for the limited area wave model Excellent Thus we enter the following additions to digatmos grd in the MODEL section Note that we refer to centre 98 ECMWF indicat ing that these model identifiers 116 128 and 216 are applicable only to centre 98 ECMWF 116
61. alue of 1 5 10 or 15 should normally be used So that the grid wraps uniformly around the globe the value you select should divide evenly into 360 Default map size When you use quick mapmaking commands such as Generate Map on the speed button toolbar this determines what the map size will be in pixels Map features to be drawn 86 Chapter Twelve PREFERENCES Use this table to set which geographical features you want displayed and in what color Remember that these will not take effect until the next time you generate a map Station plots tab Also see the special topics on Surface plot models Upper air plot mod els and Station filtering Station filtering has been moved to the Control Panel in Digital Atmosphere versions after 2002 Basic selections Plot radar status labels Whenever Overlay Radar is chosen this deter mines whether symbols are plotted at each radar location together with the radar echoes By unchecking this box only radar echoes will be plot ted Station plot units E English Quantities will be displayed in Fahrenheit and inches This only takes effect when another data plot is done E Metric Quantities will be displaced in Celsius and millimeters This only takes effect when another data plot is done Surface plot model These settings only apply when the active level is the surface level and Overlay Data is selected E Plot wind barb If checked Digital Atmosphere will plot a wind barb
62. and choose Copy Image Location Paste this under URL in digatmos rdy In this case the image is at http metsys weathersa co za ra dar_image DN gif Under FMT we need to enter the image format type Typically you just use the extension on the URL which in this case is gif Other types seen may be jpg and png Some sources use the wrong image type on the filename in which case the image will not display in Digital Atmosphere and you will have to see if the site is posting say a JPG using a PNG filename this kind of thing is happening with Canadian radar images Now we need to develop a color table to tell Digital Atmosphere which radar colors contain information Scroll to the bottom of the digatmos rdy file and start anew TABLE line using a value that is not in use If you re using the default Digital Atmosphere digatmos rdy file you ll probably be starting a TABLE 05 line So enter TABLE 05 followed by two forward slashes and a note telling you what this table is for We recommend TABLE 05 South African radars Now we need to enter the color information for each intensity level The South African radar source has a handy scale on the right side View this in your graphics program Now you need to use whatever tool will let you hover over pixels and show you the color value using RGB numbers i e three numbers each ranging from 0 dark to 255 bright indicating the nu merical level of red green and blue In PaintShop Pro
63. and is no longer available The Import Directory command imports all files contained in the select ed directory while Import Specific File imports one single file The data files chosen should consist of text bulletins containing METAR synoptic SAO FD winds aloft buoy reports rawinsonde or other compatible data After the data is imported it can then be plotted or analyzed If you use the Internet you can avoid all use of this command by us ing Internet Retrieve Data Digital Atmosphere will automatically execute an import when data is retrieved 18 Chapter Three FILE MENU Never import a directory containing binary files programs or over 100 files The results may be unpredictable Import GRIB GRIB is a standard format for binary data interchange between weather agencies most notably for the exchange of numerical model forecast data Digital Atmosphere offers the ability to view this data Although we strive to give you substantial amount of protection from the sheer complexity of the data a working knowledge of GRIB is important to getting the most from this data A full chapter on GRIB data is contained in this manual and it deserves study A few data sources may store the data in a compressed format such as ZIP or BZ2 BZip2 You will need to decompress the data using a third party program before it can be used in Digital Atmosphere Once Digital Atmosphere has examined the file you will see a dial
64. ar value is 9xx x or 10xx x The default floor 84 Chapter Twelve PREFERENCES value for lowest METAR pressure is 960 mb which means that if a value such as 584 is found Digital Atmosphere will assume it is 1058 4 mb not 958 4 mb Normally there is no need to change this but if you re looking at exceptionally low pressure areas and the sea level pressure contours aren t plotting correctly you ll want to decrease this value Likewise if you re looking at very high pressure and the sea level pressure contours aren t plotting correctly you ll want to increase this value The rule of thumb is if it s a high make it high if it s a low make it low a good rule of thumb is to temporar ily adjust it by 20 mb Be sure to change this back when the weather system is gone E Earth s rotation constant Specifies the earth s rotation in radians per second which is normally set at 0 000007292 Naturally there is no need to change this unless you want to tinker and see the results The earth s rotation constant is used in the Coriolis parameter equations which are used for geostrophic wind calculations and calculation of absolute vorticity Hitting reset replaces any entered value with the Earth s rotation constant E Gravity constant Specifies the gravity acceleration which is normal ly set at 9 806 m s 2 There s no need to change this unless you want to tinker and see the results Gravity is only used in the calculat
65. arnes method e fi Pr Then a final pass is made using multiple observations for each gridpoint A distance dependent weighting coefficient w is determined for each observation point throughout the iterations Z oe Lun e w S k 1 n w where wk a gt d j ad 2 The difference field or error field is then added to the first guess field to produce a refined analysis field Joy a tZ Then the convergence counter value a is decremented by p as shown below These values are not processed into the equations they are only used to loop the Cressman iterations as necessary a a p If a lt 0 the objective analysis is complete and the resulting field f is valid Otherwise further convergence is necessary so that the difference values of dk are reduced to lower and lower values resulting in more Appendix ANALYSIS THEORY 145 accurate values of f Program flow cycles back to the difference field calculations to achieve this Numerical operators HaltinerSmooth This is a one dimensional smoothing operator which is a modified version of the Haltiner smoothing operator defined in Haltiner 1971 The smoothing coefficient s is obtained from the user defined value of 0 1 found in the Preferences gt Analysis gt Smoothing Coefficient menu The value of each gridpoint f is smoothed using iterations in all four x y directions as described below in Steps 1 4 This is done to prevent smear
66. ation the wind declination relative to the map is recti fied through the WindDeclinationCorrect function This angle q is the declination produced by plotting a point 300 miles north of the station through a forward coordinate transformation allowing flexibility if another coordinate transformation is in use and preventing the need to devise reverse coordinate transformations From there it is a simple matter to calculate wind component u v as follows u 1 sin g V 1 cos q V where V is the wind velocity Relative humidity Calculated according to fk MixingRatio T p MixingRatio T p Wet bulb temperature Calculated according to WetBulb T T_ p Heat index Calculated according to HeatIndex T T p Humidex Calculated according to Humidex T T Equivalent potential temperature Calculated according to EqPotTemp p T T Potential temperature Calculated according to PotTlempK p 7 Precipitation type Freezing rain is triggered by ww values of 56 57 66 or 67 Ice pelleters are triggered by ww values of 79 87 88 or 89 Snow is triggered by ww values of 70 75 and 83 86 Rain is triggered by ww values of 50 55 60 65 58 59 68 69 or 80 84 IFR MVFR MVFR conditions are triggered by ceiling less than 3000 ft or visibility less than 8046 meters IFR conditions are triggered by ceiling less than 1000 ft or visibility less than 4828 meters LIFR conditions are triggered by ceiling les
67. chnique does something like this It maps data to gridpoints and fills in unassigned gridpoints using the nearest data value a process known as expansion However if the temperature in San Francisco is 52 and in Los Angeles is 85 and as suming we have NO other data the analyzed field anywhere in Califor nia will show either 52 or 85 degrees This is clearly not correct so after expansion Digital Atmosphere runs a smoothing algorithm Smoothers smooth out the mesh by changing the value at each gridpoint to an average of itself and its neighbors Unfortunately this can dampen out features in the field Too much smoothing will remove all of the short wavelength features A better way to do this is to use the Weighted Barnes or Cressman techniques These techniques look at each gridpoint find where it cor responds to on the earth and from that location it looks at the values of the stations around it and figures out a carefully averaged value best representing what the value at that gridpoint probably is The Barnes algorithm goes a step further by going back and seeing how incorrect its mesh turned out to be then adjusting that to produce a final analy sis The Cressman algorithm does the same thing but it also begins its analysis using values at stations over a wide area then gradually tight ens up its analysis running corrections and using values at stations over 61 CHAPTER 7 Radar menu This dropdown menu provides
68. clock set to Greenwich Chapter Five DATA MENU 45 Mean Time you will have to set the Windows time zone to GMT rather than Eastern Time Automatic directory search If you begin a URL with 1 such as Sihttp www mysite com data mydat this instructs Digital Atmosphere to search the directory to find the most recent file In this case it would search http www mysite com data The filename on the end in this case mydat is used as a wildcard to find matching files so files like mydatafile txt and mydata084 dat would be included while wxdata dat would be discarded If you omit the filename all files in the data directory are included in the search It is not advisable to use this directory search function with all the products in your Internet table because with university servers processing METAR and SYNOP data coding errors may result in the creation of extraneous files that do not contain data The directory search function is recom mended instead for certain NEXRAD and other products on certain servers when there is no way to effectively predict the filename Also be aware that some servers are unable to present directory listings due to security reasons Pointer page search If you carry a URL with two parts separated by a space it indicates that a pointer search will be done This is commonly used for dynamically generated web pages where the target URL is not known The first portion is the pointer URL and the
69. d Overlay gt Basemap Example of a 2500 x 1250 pixel planetary map used as an underlay 38 Chapter Four MAP MENU Add overlay Redraws the workchart basemap without erasing the contents of the workchart Basemap Overlays the basic geography basemap Counties Overlays United States counties parishes and certain city border infor mation After this is done the basic geography is re overlaid onto your map The source file is highly detailed condensed from U S Geologi cal Survey data and has an accuracy of 1 mile There are about 175 000 points in the county boundaries file so it may takea few minutes to plot on slower computers The County Name plot overlays the names of the counties The names are truncated according to the zoom factor so that they fit within the county Users can edit the locations of these county labels as well as their text content by editing the plaintext file DIGATMOS CXT with any text editor such as Windows Notepad Highways Overlays United States interstate highways onto the map The second ary highways option overlays United States U S and state highways onto your map This is a detailed process and may take a few minutes on slower computers Cities Overlays predefined city marks and labels onto your map as a reference Before you can use this successfully you will need to define the cities you want drawn by editing the file DIGATMOS CIT with any text editor such as Windows Notepad
70. dded import of MADIS data direct from FSL NOAA This is included in anew Internet Retrieval resource list Improved Internet Retrieval system to stream downloads into individual files so binary files like MADIS and future GRIB BUFR can be properly handled Files are captured under different names in data and are processed out to the Digital Atmosphere home directory under obs asc obs bin and nids bin The obs nids and madis 000 files are deleted before each new download This also allows better management of content inside data directory 12 30 06 12 31 06 Added pointer URL search function in Internet gt Retrieve This was necessitated by the way SPC carries convective outlooks and the fact Appendix VERSION CHANGE SUMMARIES 165 that no static pages for this product exists In Internet gt Retrieve URLs with a space in the middle are handled as pointer URLs See the Internet gt Retrieve help for more information 12 30 06 Fixed convective outlook plotting Changes in entire bulletin format prevented the plotting routine from working 12 30 06
71. direct access to United States NEXRAD WSR 88D Doppler radar imagery It accesses Level III high resolution data directly from sites that carry the data feed Because there are over 100 radar sites and 31 products at each site that can be used operationally Digital At mosphere has implemented a completely separate unique system for retriev ing data The Data gt Retrieve interface used for normal weather data is not used Rather all choices for obtaining data are built into the radar menu To use the radar menu you simply 1 make sure the station you want is set with Set NEXRAD Station or Quick Pick and 2 click on the product you want The image will be downloaded taking anywhere from 1 to 30 seconds and will be displayed immediately on the current workchart Special note about choosing multiple stations Digital Atmosphere can only access a handful of stations at a time It cannot access all stations in the U S because currently no server provides current data combined in one file and accessing each file individually would take several minutes of time Digital Atmosphere is also intended to be a tool to view local storms and phenomena rather than to build national mosaics which are readily available on the Internet from countless sources If you select two or more stations polygons created by radar products may overlap Digital Atmosphere does not yet have a function for prioritizing polygons based on proximity to a radar
72. e if you think you re having trouble contacting us as email addresses may have changed We answer all E mail though on rare occasion it may take several days STANDARD AND PROFESSIONAL VERSIONS For quite some time we have needed to raise prices significantly to cover the costs of development Digital Atmosphere was fixed at 68 from 1996 to 2004 and its features now greatly eclipse what was available then However we also recognize the need to provide an economical version of Digital Atmo sphere Therefore we provide a Standard and a Professional version Here are the differences between the two versions Standard version Maps Limited to vector mapped workcharts same as in previous versions of Digital Atmosphere New York City aeronautical coverage only Menu scripts Limited to a maximum of 30 dynamic scripts in your menu Registration We send you a key for the program to work beyond 30 days Professional version Maps Includes CD packed with 4 scales of aeronautical grade raster base map charts 5 for south central US excellent for radar tracking Menu scripts Unlimited scripts in your menu Registration No key is required Ideal for industrial and government use Can be moved from machine to machine Licensing is on the honor system Vector basemaps This graphic uses the native built in mapping capabilities of Digital Atmosphere showing boundaries county lines and highways Raster basemaps T
73. e mapped to the closest gridpoint then are mathematically expanded to neighboring unfilled gridpoints in a 88 Chapter Twelve PREFERENCES cyclical manner Afterwards a selective smoothing operator smooths gridpoints performing more smoothing iterations performed on gridpoints that are further from representative data areas and less or no smoothing passes where data is close to a gridpoint Strengths It s fast and always works Weaknesses Data void border areas look linear and data void interior areas can look pie shaped E Weighted Digital Atmosphere looks at the neighboring stations around a gridpoint giving it an average of those values around it with more emphasis on the values at closer stations E Barnes The Barnes method the cornerstone of the MCIDAS and GEMPAK weather workstations has a number of advantages versatility simplicity and speed Each gridpoint is assigned a meteo rological value which is the result of a Gaussian distance dependent weighting function A difference field is calculated which determines how far off from reality the analysis field appears to be then a dif ference correction is applied to the analysis field This takes a rela tively long time to compute but is one of the more accurate analysis algorithms E Cressman Each gridpoint is assigned a meteorological value which is the result of a distance dependent weighting function The Cress man analysis method is similar to the Barne
74. e script by using the ANALYZE command Scripting locations A script is made up of a group of commands on one line There are two ways of executing a script 1 On the command line in the Toolbox under the Scripting tab 2 In the DIGATMOS MNU file which is used to build the Analysis dropdown menu This may be edited by hand The pipe symbol is used to separate the title from the script form and may be placed any where between the two providing it is padded with spaces only The Standard version is limited to 50 defined script commands the Profes sional version is unlimited Command sentences A sentence of analysis script code follows the strict order output transform base setup 1 Digital Atmosphere processes the script from RIGHT TO LEFT so that any optional setup is done such as setting the level then defining the base field to be worked on such as temperature then transforming such as converting m s to kts then producing output such as setting a contour interval and then displaying contours Deviation from this form may cause unpredictable results 132 Appendix ANALYSIS SCRIPTING 2 Users must be vigilant as to whether a scalar or vector field is be ing processed For example CONT WIND will result in a nonsensical output because wind is a vector field and cannot be contoured you can streamline it but that command hasn t been provided yet To view wind speed you will need to extract a
75. e to examine the imported contents METAR data 340322 bytes SAO airways data 14702 bytes SYNOP data empty FD data empty RAGB data empty AIREP data empty ASCII model data femotv 19552 Z1006KT 1SM RA OVCO10 04 02 42979 RMK ESTIMATED PASS CI a IMPA 19422 OSOO6KT 7SM SCTO3O 32 21 A2992 RMK 8 100 RTS K474 1948Z AUTO 1400SKT 3SM HZ 29 07 A3019 RMK AO0Z KVUJ 19452 AUTO 19008KT 10SM SCTO60 31 11 A30Z2 RMK A0Z IKPRN 1956Z AUTO OSO09KT 9SM CLR 29 13 A3011 RMK AOZ SLPOSZ TOZ9401 MDPP 2000Z O9004KT 6000 RA SCTO1S OVCO70 28 26 Q1013 MDCY 2Z000Z 1800SKT 8000 RA BKNO16 OVCO70 28 25 Q101S MDPC Z000Z 13006KT 9999 FEWO16CB FEWO1LS SCTOSO0 BRN3OO 30 25 Q1012 C MDJE 2000Z 1800SKT 4000 RA FEWO14CB BKNO16 OVCO70 27 24 Q1013 CB Eys IMDLR Z000Z Z20010KT 9999 BKNO1S BRKNO7O0 28 26 Q1013 IMDBH 20002 16010KT 9000 RA FEWO14CB BRKNO16 OVCO80 27 25 Q1015 CB MDSD 20002 Z7006KT 7000 RA FEWO1L7CB BRNO1 OVCO70 27 25 Q1013 2000Z OSOO4KT 9999 SCTO16 SCT100 32 26 Q1009 NOSIG ofl Close Troubleshoot Data panel Hurricane tracks This option plots hurricane tracks from the National Hurricane Center NHC or Joint Typhoon Warning Center JTWC forecast advisory bul letin WTNT WTPZ WTPN WTIO and WTXS This shows the cur rent and forecast location of hurricanes typhoons and tropical storms A track connecting each forecast point is created using a mathematical spline The sou
76. e were extracted from NCEP source code written by ESSA or NOAA programmer Gloria Dent around 1970 and may very well be some of the oldest computer fonts in use anywhere See the illustration on the facing page Other settings Additional settings for contouring may be found in Preferences gt Analy sis gt Isopleths Get archived data If you have the Surface Archives or Upper Archives disc sets from Weather Graphics Technologies you can use this option to retrieve data on the disc instantly Digital Atmosphere will decompress and ingest the desired datasets enabling you to plot maps of any date and time be tween 1961 and 1990 and earlier and later in some cases In the above example we ve specified that we want data for September 4 1972 at 1700 UTC Greenwich Mean Time It is assumed that the Surface Archives 1961 73 disc is in the drive if the wrong disc is in the drive you will get an error Once the Import item is selected the data will be imported You can then use commands such as Data gt Plots and Analysis gt Sea Level Pressure to view the data Quality control If you re a newcomer to meteorology you ll quickly discover that not all weather data is 100 accurate Errors can get into raw weather data either through transmission problems communications interference hu man error or simply the observer hitting the wrong key when typing up 22 Chapter Three FILE MENU the report These can either be
77. ed E A shapefile only holds one feature class of data It cannot for example hold county outlines and city outlines as separate entities You do not need to have dbf and shx attribute files to use a shapefile you only need the shp file E Shapefile creation is not a simple task but may be accomplished in programs like ArcView MapObjects MapMaker and Manifold E To delete the existing Digital Atmosphere basemap use Map gt Blank Map before importing a shapefile Otherwise the shapefile will be painted on top of the map E Digital Atmosphere does not export shapefiles at all E Be careful using street level data as Digital Atmosphere is not de signed for extremely tight zooms Digital Atmosphere is not a street level mapping system Important notes A lot of money is floating around in GIS geographical information systems technologies and there seems to be very little interest in the free exchange of shapefiles Therefore don t be surprised if you can t find a shapefile or if you see prices that will break your budget On the other hand there are a good number of free shapefiles around especially for odd regions but you may have to scavenge government and private websites to find them We cannot help you find shapefiles However some possible sources include http www manifold net download freemaps html http www nws noaa gov geodata http data geocomm com catalog index html Chapter Four MAP ME
78. ed to use the Erase Map command to get rid of the data before you save it If you want to save the map for your projects presentations and so forth in one of several graphics formats you should instead use Map gt An important consideration is that only Windows bitmap BMP files can be saved and they are rather large File sizes can range anywhere from 300 to 700K in 8 bit color mode to several megs in 24 bit color mode Avoid saving too many unless you have plenty of disk space If you re using on the fly disk compression such as Stacker DoubleSpace DriveSpace etc these images will take up about 80 less disk space than they do when uncompressed 28 Chapter Four MAP MENU OILL_ FOR ADVANCED USERS Save Map produces one image file a Windows bitmap BMP and a very small map attribute file DMF The DMF file is nec essary to load the map into Digital Atmosphere and should stay in the same directory as the DMF file The internal structure of DMF files is explained in the Appendix Once the BMP file is saved you are free to use any graphics editor to tweak or annotate the image Note that you must re save it as the same type of graphics format it was in a BMP with a color depth of 24 bits or Digital Atmosphere will produce an error message when it attempts to load the image sells hitb SIO VUUIUUULULUULULLLLLLUL ULL ULULULLULLLULLLULULUULUULLLL LUL LULUULUULL LUL LULLLLULLLLULULLLLULULUULUUL LLULLU LULLLLI LLULLU
79. eferences and regenerate new maps preferably with white backgrounds then print those Also keep in mind that many PostScript printer drivers will allow you to set the printer to produce negative printouts If the maps are too dark you should avoid using solid colors Regenerate your maps without topography or ocean fills Topography is designed mainly for screen viewing If you absolutely must have dark maps on screen and can t force your printer to produce acceptable output either through File Print Setup or through the printer s own setup menus you will need to export the map and then use a photo editing type graphics program such as Photo Shop or Paint Shop Pro to make a negative image or enhancements that allow for better printouts Fitting an image to the printer Printouts of Digital Atmosphere maps will be clearer if the graphic image exactly matches the generated printer image To do this first establish which dpi dots per inch the printer will produce For many printers this is 300 though 600 or 1200 may be possible Then determine the printable image size For instance many HP printers use a quarter inch border all around when printing to 8 5 x 11 paper which yields an image size of 8 x 10 5 Simply multiply this dimension by the dots per inch to get a suggested image size in pixels Thus 8 x 10 5 multiplied by 300 dpi yields 2400 pixels in width and 3150 pixels in height So do a Map gt Generate with these image
80. eing drawn terminates and further drawing is begun using a trough Low When pressed any line being drawn terminates Any click on the workchart will produce a low pressure area High When pressed any line being drawn terminates Any click on the workchart will produce a high pressure area Text When pressed any line being drawn terminates You will be prompted for text and allowed to place it on the workchart Suspend highs lows Highs and lows are omitted from the map Helpful hints Drawing a front So that the barbs point the correct way as you draw the line cold air must always be on your right side except when drawing warm fronts the easiest way to remember this rule is to al ways start from the center of a low pressure area and work your way to higher pressure Simply set the cursor on the first point choose __ front then move along the front and right click Frontal depic tion tools gt Add front point at each point to define 3 or more points along the front The front will be drawn as you go along and will be smoothed auto matically as a spline Run Create Drawing highs and lows Simply right click on the map and choose Frontal Depiction Scheduler is off Tools gt Add high low to mark the position of a high or low pressure area You will be prompted for a central pressure in millibars You can leave this blank if you wish not to specify one Scripting tab This panel is meant for advanced user
81. em we ve made it easy Simply give them a copy of your DIGATMOS SLZ file it s in your Digital Atmosphere directory If they replace their DI GATMOS SLZ file with yours they ll get your list of data products We sometimes offer updated DIGATMOS SLZ files on our web site to give you the latest set of data products Password security Note that you can set a password privately by using the DIGATMOS PWD file if there isn t one you may create it This will make your scripts secure and prevent passwords from showing up in the status windows This file must be located in the Digital Atmosphere directory Make entries as follows token value So if you have a login for your blog site you might have something like this in your DIGATMOS PWD file myusername joeblow mypassword 12341234 When Digital Atmosphere encounters ssomething in your URL it will replace it with the values you defined in DIGATMOS PWD Thus in the example above myusername would get replaced with joeblow and mypassword would get replaced with 12341234 Update Internet table Causes Digital Atmosphere to update itself with the most current Inter net resource table from Weather Graphics As of May 2007 this com mand does not work Chapter Five DATA MENU 47 Data plots Overlays data plots on the workchart Symbols shown conform to standard international convention A weather type of double solidus indicates unknown precipitation as r
82. en value So if you have a login for your blog site you might have something like this in your DIGATMOS PWD file myusername joeblow mypassword 12341234 When Digital Atmosphere encounters something in your URL it will replace it with the values you defined in DIGATMOS PWD Thus in the example above myusername would get replaced with jo eblow and 7omypassword would get replaced with 12341234 INGEST filename Imports the specified data file filename is a fully qualified file name RADAR COMMANDS RADAR product station Retrieves the desired radar product from the given station Station is a 3 letter station identifier e g FWS EWX etc Multiple stations are separated by one space character Product is the Radar Product Code from the table below RADARPLOT 126 Appendix SCHEDULER SCRIPTING Plots the latest retrieved radar data RADARSAVE filename Saves the latest retrieved radar data to a given filename IMPORTRADAR Imports an imagemap radar using parameters selected in Radar gt Im port Radar Images DERIVED PRODUCT COMMANDS HURRICANE Imports hurricane bulletins HURRMODEL type Plots hurricane models The type is as follows 0 splines only 1 splines and datapoints 2 splines datapoints and labels FLEET Plots all fleetcode information FLEETHL Plots fleetcode bulletins with only highs and lows FLEETF Plots fleetcode bulletins with only fronts FLEETI Plots fleetcode bul
83. enter position 0f304 367 X 304 Y 367 Enter this into di gatmos rdy under XXX YYY So far it should look like this Now we need to find the top left and bottom right of the part of the image containing valid radar information This image has a border box enclosing the radar product the legends are outside of it and the radar image is inside of it We can use the border box The top left is 0 54 and bottom right is 612 665 Enter this under LEFX TOPY and RGTX BOTY Now we determine the maximum range of the radar scan This can be seen easily with the 200 km ring So the range will be 200 km Enter that under RNG Now we need to determine a scale in pixels per km This is an easy task since the range rings and site center are obvious Since the leftmost extent of the 200 km ring is at X 0 and the radar center is X 304 this means that we have 304 pixels per 200 km of distance Do the division and we get 304 200 1 52 Fit this figure under SCALE 100 Appendix IMPORTING RADAR GRAPHICS Now put the latitude and longitude under LATITU LONGITU Note that if your figures came in degrees minutes seconds you need to convert them to decimal values before entering them here Fortunately the South Africa radar information page gave us decimal degrees Always use negative for westerly longitudes and southerly latitudes So we will be entering 30 01 30 93 Now let s get the URL of the image Simply right click on the radar image in your browser
84. eported in an automated METAR observation The meteorological level at which the data applies is dictated by the Level setting on the Toolbar Custom data plots Plots data on the workchart from a custom data file Note that whether a point of data is plotted DOES depend on the Pref erences gt Station Plots gt Plot All Stations settings To see absolutely all datapoints check this setting so all points are plotted otherwise they will be plotted in a way that minimizes overlapping A custom data file comprises a package of data that can be readily im ported into Digital Atmosphere You can create this data by any means using third party programs The custom data field must always be placed in the file CUSTOM DAT in your Digital Atmosphere directory It should be structured according to the following example THUNDERSTORM DAYS ALL MONTHS US AL Bir 722280 33 567 86 750 57 US AL 0za 722269 31 283 85 717 73 US AL Hun 723230 34 650 86 767 54 US AL Mon 722265 32 383 86 367 56 Here is a breakdown of each row and column Row 1 A header that will be used by Digital Atmosphere to title the field Row 2 Data as explained below in data row format 48 Chapter Five DATA MENU Data row format Col Contents 1 19 Not used User may put location names here 21 29 Latitude degrees and thousandths 31 39 Longitude degrees and thousandths 41 49 Primary data value 51 59 Secondary data value Southern hem
85. ere s depiction Since the ASUS1 s fields are coarser and may differ from the isopleth fields you should gener ally leave this unchecked unless you have no surface data and want to see the ASUS1 output of highs and lows E Display pressure values when plotting frontal bulletins E Winter depiction extend contours over nonprecipitating areas E Convert ALSTG to SLP for analysis advanced users only FOUS data level Whenever you plot model ETA NGM data the temperature and mois ture variables are determined according to this setting Normally the first button T1 R1 is selected to give you surface data but by choosing another button you can plot or analyze temperature or moisture aloft calculating derived values such as dewpoint should be done with cau tion though since T3 is not the same level as R2 Here are the meanings of the different levels Level Equivalent T1 Surface T3 About 100 mb above the surface 1 km T5 About 215 mb above the surface 2 km R1 Surface to about 35 mb abv sfc lowest 1000 ft R2 About 35 mb above the surface to 500 mb R3 500 mb to the tropopause CAPE mixed layer depth Calculates the depth of the layer to use when performing mixed layer stability Miscellaneous quantities E Lowest possible METAR pressure The METAR surface observa tion code format only allows the tens units and tenths place to be encoded which means that Digital Atmosphere has to determine whether the final millib
86. fferent from the Processed Data File OQUTPUT in that every observation is applicable to the on screen analysis window matching the domain and the chosen date time Data outside the on screen analysis window is discarded Build2DGrid This function uses the Domain Data File constructed in BuildWeather DataFile to map the data to a two dimensional grid For each observa tion point the latitude and longitude is evaluated in respect to the screen window the domain available to the user in a screen window The Appendix ANALYSIS THEORY 141 observation is assigned a real number x coordinate x 0 30 and y coor dinate y 0 30 as follows x x x 30 y y y 30 where x y is the coordinate of the observation on the screen map in pixels X Y is the size of the map in pixels x y is the coordinate of the observation in grid units 0 30 Then the appropriate observation parameter is determined using the value only if valid data for the parameter is present in the observation The station pressure p was determined in the BuildWeatherDataFile unit Temperature dewpoint sea level pressure altimeter setting wind speed height The value is used verbatim A conversion to metric units may be accomplished Wind components Background maps are never displayed in Car tesian coordinates therefore it is necessary that the declination for a given station be obtained If a wind component is to be calculated for any wind oper
87. formation on building an analysis script command please see the Analysis section FONTTRUETYPE Forces workchart fonts to TrueType mode Takes effect when new prod ucts or contours are displayed FONTNCEP Forces workchart fonts to NCEP raster font mode Takes effect when new products or contours are displayed SFCPLOTMODEL filename Loads a particular surface plot model Filename must be the fully quali fied filename with path and extension sps Appendix SCHEDULER SCRIPTING 125 DATA MANAGEMENT COMMANDS DOWNLOAD url filename Downloads a product from an Internet source The url is the fully quali fied RFC 1738 standard URL including filename and filename is the full local name where the file will be stored Example download ftp userid password ftp mydomain com anonftp pub out jpg c da20 bin map in jpg UPLOAD url filename Uploads a product to an Internet source The url is the fully qualified RFC 1738 standard URL including filename and filename is the full lo cal name of the file to be uploaded Example upload ftp userid password ftp mydomain com anonftp pub out jpg c da20 bin map out jpg Note that you can set a password privately by using the DIGATMOS PWD file if there isn t one you may create it This will make your scripts secure and prevent passwords from showing up in the status windows This file must be located in the Digital Atmosphere directory Make entries as follows tok
88. g con vergence of the data to observed interpolated values using multiple iterations NOTE If automatic smoothing is enabled the average station spacing value is set to a a 1 333 First the number of convergence iterations p is established The value q originates from the Reduction value specified in the Preferences gt 144 Appendix ANALYSIS THEORY Analysis panel The value a is the average station spacing as determined above p alq The predicted value f is calculated for a gridpoint using all observa tions k 1 n A distance dependent weighting factor is determined for each observation before summing it into the equation The value d is the distance between gridpoint f and observation f in units of a therefore d Ja 0 1 I Aa Te Len expe S k 1 n w where w d a At the completion of the above calculations a difference pass is run to compare the error of the actual data value f against its interpolated predicted value p within the objectively analyzed field The value i and j refer to the fractional coordinate of the observation 0 1 within its sur rounding objective analysis grid box of x x 1 and y y 1 The calcula are done as follows Goa whe y i f y H Gea y a x ya ht x pa T KE w Dfe t amr D tfa 1 4 The difference between the observation value fk and its predicted value pk establishes an difference field an error field ek in much the same way as the B
89. ge width height respectively to one of several preset values About raster graphics Our prepackaged raster graphics are considered a premium feature and are only available in their entirety in the Professional Version on CD ROM Raster graphics are highly useful for real time radar analysis of storms due to the vast amount of geographical information they convey In the standard Digital Atmosphere version coverage is only available around the New York City area for evaluation purposes In the Profes sional version there is coverage of the entire United States except 1 250K Joint Operation Graphic which is limited to the south central U S All raster graphics are drawn in the Cartesian projection which causes slight but inconsequential distortion in the northern and southern U S 30 Chapter Four MAP MENU al a Image of supercell with raster maps Professional Version underneath This uses the 1 500 000 Tacti cal Pilotage Chart series that covers the U S Blank map Creates a workchart with absolutely no graphical content i e completely blank Digital Atmosphere is however aware of the cartographic details of the workchart pane and can still plot to it Import map from file url Imports an existing basemap into Digital Atmosphere without chang ing the geographical coordinates This command is mostly for advanced users who are importing satellite photos into Digital Atmosphere Users should always use Load Basemap
90. gt Add Overlay gt Highways You will see Interstate high ways appear on the map 3 Now click Map gt Erase Map You will notice that the county outlines have disappeared This is a very important concept The basemap is persistent but map annotations weather charts and so forth are not Fortunately if you want to preserve the counties as a permanent annota tion until the next time a map is generated here is how to do it 4 Click Map gt Add Overlay gt Highways You will see Interstate high ways appear on the map again 5 Click Map gt Copy markings onto basemap Now all annotations drawn on the map are permanent until the next time a map is generated 6 Click Map gt Erase and you will note that the highways remain on the map Measuring distances Did you know you can measure distances with Digital Atmosphere Simply put the cursor over a certain spot on the map and hold down the left mouse button as you move the mouse around Notice that you see a box and a line that moves with you The line helps show you the path between your two points The box defines an area which you will use later to quality check a group of observations At the bottom of the window however note that the status bar is dis playing the latitude and longitude of each point and the bearing and distance between the two The line drawn on the map is actually a great circle line and on global map views you will notice that it forms an arc rather tha
91. habetical character that will be used to represent low pressure and high pressure areas Typically L is used for low pressure and H for high pressure but this will vary in non English countries The Include value option determines whether the pressure value in millibars will be plotted with the high or low E Title Allows a title determined by the most recent meteorological field to be displayed to be plotted on the workchart at the given position E Credits Allows a user defined credit to be plotted on the workchart at the given position Logo This option allows you to insert a logo on your workcharts E Source filename If entered specifies the name of an image GIF or JPEG Click on the button to choose a file from a menu or simply type in the name in the box provided Press Clear to disable logo use E Position Specify the location top right top left bottom right or bot tom left where you want the image on the workchart and specify the offset in pixels on the X and Y axis Values of 0 place the logo flush with the corner of the workchart while values of 10 to 20 will provide a buffer 94 APPENDIX 96 97 APPENDIX Printing Digital Atmosphere s Print command sends an exact copy of the screen image to the printer Here are some tips for troubleshooting your map printouts Image brightness and contrast f the printouts are too dark you will need to change your map settings in Pr
92. he database to be displayed Plot date labels at each track Digital Atmosphere will plot a MM DD YY label to the lower right of the beginning of each tornado track to show which date the track occurred Color code If checked Digital Atmosphere will code a track black if there were no reported injuries or fatalities green if there were fatali ties but no recorded deaths and red if deaths occurred The source of data is the Storm Prediction Center historical tornado archive located at http www spc noaa gov archive tornadoes To save disk space the data has been converted into a series of binary records stored in digatmos tor that have this structure Year signed 32 bit inte ger month unsigned 8 bit integer day unsigned 8 bit integer hour unsigned 8 bit integer minute unsigned 8 bit integer fujita rating of which very little data is available unsigned 8 bit integer fatalities signed 32 bit integer injuries signed 32 bit integer latitude of begin ning 4 byte float longitude of beginning 4 byte float latitude of end 4 byte float and longitude of end 4 byte float Weather Graphics does not object to users providing their own updated tornado statistics to replace this one 74 79 CHAPTER 9 GPS menu Digital Atmosphere supports the use of Global Positioning System devices Your GPS unit will need to output data in NMEA format What you do with these instruments and how they can work with Digita
93. he largest makers of such boxes They cost about 30 74 CHAPTER 10 Window menu Cascade Causes all open workcharts to stack on top of one another visually with the title of each one visible Tile Causes all open workcharts to expand and fill a proportionally equal area of the screen Arrange icons Remove last product Removes the last product plotted Replot last product Replots the last product Allow Digital Atmosphere to run in background 78 This prevents Digital Atmosphere from coming to the foreground which may cause distraction when working in other programs Add remove toolbox speed buttons status You can add or remove toolbars as needed to make more space on your workchart Remove last product Removes the last data overlay from the screen 79 CHAPTER 11 Help menu Contents This shows the Digital Atmosphere HTML Help file We began focusing on PDF and printed manuals in May 2007 so some of this information may be somewhat outdated Itis kept for the sake of providing a conve nient quick reference Register If this menu option is not seen your program has been registered already The Help gt Register dialog allows a user to unlock an unregistered version of Digital Atmosphere It usually only needs to be done once The trial version will be converted to a fully registered version even if it has already expired A key number is only available from Weather Graphics
94. he range 2 9 x 10 39 1 7 x 1038 with 11 12 significant bits and a length of 6 bytes Integer types have the range 2147483648 2147483647 and are signed 32 bit 4 byte little endian 112 113 APPENDIX Field and product codes OBSERVATIONAL PRODUCTS Product codes pla ACARS plots plf Standard data plots plc Custom data plot tdy Television style data plots rad Radar plots sf0 Europe sferics 0 hr sf6 Europe sferics 6 hr wgr Wind grid Field codes tmf Temperature deg F tmc Temperature deg C pot Potential temperature deg K wcx Wind chill factor hix Heat index dwf Dewpoint deg F dwc Dewpoint deg C rhu Relative humidity mxr Mixing ratio eqp Equivalent potential temperature theta e slp Sea level pressure alt Altimeter setting QNH wsp Wind speed cig Ceiling hgt Geopotential height thk Thickness 1000 500 mb wrx Warning overlays p01 1 hour precipitation p06 6 hour precipitation p12 12 hour precipitation p18 18 hour precipitation p24 24 hour precipitation rst RCM radar storm centroids rhl RCM radar hail signatures rms RCM centroid movement and speed rtv RCM tornado TVS signature reh RCM echo height signatures rem RCM echo movement wxp ASUS1 KWBC frontal depiction bulletin 114 ste pdw htw hti pdd htd dit di2 pd1 ht1 pd2 ht2 cig dy1 dy2 06k lel bet be CXX hux iht zb prt Appendix FIELD AND PRODUCT CODES Sea surface temperature Wave pe
95. he same storms viewed with the 1 500K TPC topographic raster map set that comes with Digital Atmosphere Professional The Professional version uses the basic vector maps by default but these topographic maps can be displayed upon request CHAPTER 1 Tutorial Let s begin with a quick tutorial to help you get up and running You will need a connection to the Internet If you have no Internet connection you may go to File gt Import a File and select the folder tutorial to import and view some data If you are not viewing this chapter on paper we suggest printing out this help page and following along if you re in Windows Help just go to File gt Print Topic to print this page Setting up our area of interest For the purposes of this tutorial let s start with a map of the eastern United States 1 Go to Map gt Generate 2 For Projection choose Orthographic You should use Orthographic for nearly all of your charts 2 1 x 3 Set Latitude to 40 The map will Wibworepuars be centered on latitude 40 in the Projection Orthowrapio i northern hemisphere which is Raster charts are limited to the New York City area except in the professional Digital Atmosphere version p ositive Please see the help file s Generate Map section 4 Set Longitude to 85 negative Lattude foco eighty The map will be cen Longitude feson wid oI gt tered on longitude 80 in the Seale poo 1n 6s E we
96. he wind field Go ahead and click on Map gt Erase map Now choose Analysis gt Wind gt Wind speed barbs You ll see a pretty cool gridded array of wind patterns It s the ideal thing to depict how the air is moving Also try Map gt Erase map and then Analysis gt Wind gt Streamlines Conclusion That completes the quick tour of Digital Atmosphere This tour was only intended to give you a feel for how Digital Atmosphere works You ve covered all of the basic functions and now you can build on your knowl edge by playing around with the software and reading through this help guide There s almost no way you can break Digital Atmosphere just by experimenting Have fun CHAPTER 2 Display components Before we continue let s look at five major components of the Digital Atmo sphere screen in the illustration below It s important to be familiar with each of these parts since we will refer to them occasionally through the manual This chapter discusses each component in detail 40 1371 83 3880 40 08 13 N 83 23 16 W Regular analysis style Observations 2570 total 1324 in dome 7 Main menu File Map Data Analysis Radar Climatology GPS Window Help The main menu is where you issue most commands for Digital At mosphere This dropdown menu structure works just like most other Windows programs Each main menu command will be described in the following chapters in this manual so we won t discuss
97. height m Geostrophically balanced height field m Theta e or equivalent potential temperature deg Reported pressure tendency Wind chill deg F Heat index deg F 134 Appendix ANALYSIS SCRIPTING HUMX Humidex deg C WSPD Wind speed m s WIND Wind vector m s referenced to true north WDRC Wind direction deg UGRD Wind west to east component m s referenced to true north VGRD Wind south to north component m s referenced to true north HGHT Geopotential height m SLPR Sea level pressure QFF mb ALST Altimeter setting QNH in Hg PRES Pressure mb used for upper level heights LATT Latitude deg LONG Longitude deg ELEV Elevation m TSEA Temperature sea surface deg C PCO1 Precipitation 1 hr PCO2 Precipitation PCO3 Precipitation PCO6 Precipitation PCO9 Precipitation PC12 Precipitation 12 hr PC15 Precipitation PC18 Precipitation PC24 Precipitation PCXX Precipitation unknown time period used in Australian AXF data WSWP Wave period sec WSWH Wave height m WWP Wind wave period WWWH Wind wave height WLP1 Sea swell period 1 WLP2 Sea swell period 2 WLH1 Sea swell height 1 WLH2 Sea swell height 2 WLD1 Sea swell directio WLD2 Sea swell direction screen relative screen relative TRANSFORMATIONS VKNT m s to kt VMPH m s to mph VKMH m s to km h DEGF deg C to deg F MAGN Magnitude of a vector field produces speed for a wind f
98. here Thus if other users log in they will see different Preferences settings The entire key HKEY_CUR RENT_USER Software Digital Atmosphere can be deleted with Windows Regedit if a factory reset of preferences is desired The preferences menus are divided up into several sections each of which may be accessed by clicking once on the tabs at the top of the dialog box Just click on the tab corresponding to the settings you want to change to switch between preference pages Each tab will now be introduced individually General tab General settings E Send errors to status windows Causes errors to be indicated in the Status Window rather than as a popup dialog This option is pro vided because popup dialogs requiring input may interfere with unattended scripting This does not yet support all errors in Digital Atmosphere if you see dialogs that this error does not catch write down the text in the dialog and report it to us E Automatically check for updates Causes Digital Atmosphere when first started up to check the weathergraphics com site and access a file called digatmos ver to detect whether a new version is available If a new version is detected you will be asked whether you d like to close Digital Atmosphere and proceed to the website If you choose no Digital Atmosphere will ask whether you want to be reminded about this upgrade or not 82 Chapter Twelve PREFERENCES Radar color settings E Prefer
99. hes mm E Base Determines the base value that the intervals are based off of For example if you use an interval of 5 degrees a base of zero will give 0 5 10 15 20 25 degrees If you use a base of 2 degrees you ll get 2 7 12 27 etc Always reduce the base to the lowest common denomina tor as close to zero as possible E Interval Represents the contour step interval the numerical differ ence between each contour E AI Automated interval If y is entered Digital Atmosphere will over ride the base and interval settings and choose the ones that will give the clearest view of the data field E Style Indicates the linestyle that will be used to draw the contour Acceptable values are solid dash or dot Radar echoes must be ei ther solid clear bdiag fdiag cross crdiag horiz or vert Making a new style At some point you may not be happy with just editing the default styles When you want to create a new style click the New button You will see a panel like this General Meteorological Maps Station Plats Analysis Forts Styles misc Select style AIPS dark map awips sty X New coor PaRaMeTER e Jo gt past fer ferese E est eose 240 240 140 1 240 240 140 1 240 240 1404 200 240 255 1 d A E Enter a plaintext name Choose any phrase that will readily identify the map to you A brief phrase without any brackets should be used Chapter Twelve
100. his is used to conduct a time zone test to troubleshoot problems on certain international versions of Windows When the Time button is pressed a code is presented in the box which can then be submitted to Weather Graphics via email Cities E Cursor sensitivity threshold Controls which cities will be shown when Map gt Cursor City Distance is active E Plotting threshold This controls which cities and towns will be ac cepted for use in the Map gt Cursor city distance function Reduce this number into the hundreds or thousands to allow comparisions with small towns Increase the number into the tens of thousands to allow comparisions with only large cities There is some variation in the sensitivity between different states and you may need to increase or decrease the factor for your region To get an idea of what num bers you should use you may open the digatmos cty file Miscellaneous 2 tab Copy imported data to local file This option allows the user to automatically save a local copy of all data that is imported each time an import operation is done If enabled the data will be saved to the pathname specified If you do not need this functionality leave the enabled checkbox unselected Debug GRIB data Causes the insertion of parameter number and value in the table that presents a GRIB field to display during GRIB import For diagnostic use only 93 Annotations tab Text annotations E Highs and lows Choose the alp
101. his tells Digital Atmosphere to only read sections following a DANSK block and ignore the rest of the file You can have as many different sections and section headers as you like in the file To add the foreign language entries copy all of the information in the Eng lish section and paste it below the new language header then in the Display as column write the items as you wish them to be displayed It is not neces sary to edit items under Name not used in Dig Atm but you may edit the entries to make the file more readable for you If you do not intend to use Digital Atmosphere in English you may simply overwrite the English section with your own entries Note that there is no support for Unicode at this time thus Cyrillic and other fonts cannot be plotted To change the language of the analysis options under Analysis you may edit the digatmos mnu file directly There is currently no support for dis playing the main menu in other languages 154 159 APPENDIX About weather data Weather data is something we take for granted but few meteorologists know exactly where it comes from This section helps clarify how it works Every day nearly ten thousand weather stations across the world dis seminate weather observations These observations are taken according to standards and formats laid out by the World Meteorological Organization WMO a United Nations organization based in Geneva that facilitates inte
102. ibute file dmf is saved Therefore it is designed to save maps for use in other Windows applications The output format can be selected under Save as type As an alternative to using Export Chart you may prefer to use Copy to Clipboard and paste the image into your favorite program Here are the different filetypes you can save E GIF Graphics Interchange Format This is recommended for general purpose graphic saves where file size is most important This is best for important documents and desktop publishing The palette is only 8 bit 255 colors so you may see unwanted changes in color and hue Pixel quality though is superb and it is excellent for handling fine detail such as station plot models E JPG JPEG This is recommended for general purpose graphic saves where color accuracy is most important It offers good compression but details may be lost This is a lossy compression scheme which means that some pixel detail is lost Filesize however is vastly smaller than other formats when the image is complex The palette is 24 bit but color is not accurate bit for bit due to the lossy compression scheme Some fine detail such as plot models may have very slight illegibility Compres sion settings can be modified in File gt Preferences gt Maps gt Go there to change the permanent setting E PNG Portable Network Graphics This is recommended for accu rate lossless renditions of the graphic where lossines
103. ield DVRG Divergence of a vector field RVRT Relative vorticity of a vector field pure used mainly at surface AVRT Absolute vorticity of a vector field adds Earth s rotation used for upper air SMTH Apply Haltiner smoother Appendix ANALYSIS SCRIPTING 135 SMTP number Allow this number of smoothing passes default 1 SMTC number Set smoothing coefficient O to 1 only default 0 5 SSUM f1 2 Calculates SDIF f1 f2 Calculates SAVG f1 f2 Calculates sum of fields f1 and f2 difference of fields f1 and f2 average of fields f1 and f2 SMLT f1 2 Calculates product of fields fi and f2 SDVD f1 f2 Calculates quotient of fields f1 and f2 SADC f1 Calculates sum of field f1 and any number SSBC f1 Calculates difference of field f1 and any number SMLC f1 Calculates product of field f1 and any number SDVC f1 Calculates quotient of field f1 and any number OUTPUT UNIVERSAL OUTPUT COMMANDS COLOR r g bSetdrawcolortocolorr red g green b blue each is 0 255 STOR nStorefieldin slot n 1 9 SCALAR OUTPUT COMMANDS DATA Data grid values CONT Contour defaults to contour interval of 1 VAON Allow plotting of numeric values below minimum maximum default VAOF Prohibit plotting of numeric values below minimum maximum NMCY Plot highs and lows in special NMC font default is according to Preferences gt Analysis NMCN Plot highs and lows in standard font default is according to
104. in column 5 of the station tables Use this dropdown to change how Digital Atmosphere responds to such a condition if at all E Anti crowding In urban areas symbols and labels may overlap each other Use this to control the crowding of symbols next to one another Pressing the All button sets the factor to 100 full cluttered plotting all stations E Plot only stations in this country province Use this text field to force Digital Atmosphere to ignore all symbols except those in locations that you specify The country code should be in ISO 3166 format equalling those in columns 51 53 of the station tables such as CAN for Canada and state province codes should be equal to a 2 letter abbreviation used in columns 55 56 of the station tables e g NY for New York Press Clear to reset these values to accept all sta tions Range rings Overlays NEXRAD radar range rings The primary use of this is to es tablish the limit of radar coverage for hurricanes off the coastal regions Custom overlay Overlays a custom overlay onto the map This is done in the Weather Graphix style with custom geography residing in the file DIGATMOS PLR Edit this file manually using an ASCII text editor such as Windows Notepad to make changes Note that longitude in the west hemisphere is negative so files imported from WeatherGraphix will need to have the longitude signs inverted The color of the line is controlled by the roads and custom lines
105. ing of the fields in a particular direction something that has been observed in previous implementations When this is completed the result is a smoothed data field 1 Positive Y direction iteration Iterating from f to f stepping through each value of x 0 30 f is altered as follows f 1 8 f E 0 5 E ya 2 Positive X direction iteration Iterating from f to fy stepping through each value of y 0 30 f is altered as follows f 1 8 f 8 0 5 Fa a 3 Negative Y direction iteration Iterating from f to f stepping through each value of x 0 30 f is altered as follows f 1 8 f 8 0 5 E ya 4 Negative X direction iteration Iterating from f to f stepping through each value of y 0 30 f is altered as follows fa 1 9 fy 5 0 5 fas heny QuickFilter This fast two dimensional smoothing operator is called by certain objec tive analysis routines It is essentially a two dimensional averaging op erator that uses 50 self weight and 50 adjacent weight from neighbor ing observation values The filter is iterated through each value of fx y in the y direction for each increment of x as follows la i 8 cere t x y 1 tiini a Hi aa Td aa 16 If null data or a border area contains an unusable value of f the value is not included in the summation total and the divisor is reduced by one Expansion 146 Appendix ANALYSIS THEORY The E
106. instead of Import Map unless they understand what they are doing This command simply swaps out the current workchart map image with a graphic obtained from the chosen file You may select between GIF JPG PNG and BMP formats Note that Import Map expects the coordi nate system to remain the same so you must be positive that the existing Digital Atmosphere map matches closely with the image that you are about to load Considerable experimentation may be necessary Chapter Four MAP MENU 31 The URL choice instead of Import from File is useful when the graphic that is to be loaded consists of live weather data such as a satellite im age Import shapefile A shapefile is a universal map format developed by ESRI It is designed to store nontopological geometry and attribute information for the spa tial features in a map dataset These consist of points lines and poly gons Used with Digital Atmosphere it gives you complete flexibility to develop basemaps that are designed by yourself or a third party source You can use it to display customized boundaries for important land areas and forecast regions To import a shapefile click on Map gt Import shapefile A file explorer dialog will open allowing you to navigate to the shapefile that you want to use The shapefile will be overlaid on the existing map It will not replace your current map If you want to eliminate the existing Digital Atmosphere map use Map gt Blank Map bef
107. iod This data can be viewed on a graph or plotted on your maps Keep in mind that as with most other meteorological data the results may be affected by the observing station s elevation or proximity to the ocean This is why you may see significant variations in temperature along a coastal region among other effects Extract data If you want to plot or analyze climatological data this is where to start Extract Data will allow you to select a category and timeframe of clima tological data Digital Atmosphere will then create a custom data field saving it into CUSTOM DAT in your Digital Atmosphere directory This can then be immediately plotted with Graphics Plot Custom Data or analyzed with Analyze Custom Data Field You can even import the data into a spreadsheet or database program Graph This option will let you graph the climatology for any of 2 000 stations around the world Simply enter a partial word or country digraph to search for a station or choose from the drop down list What you ll see is a graph of average high and low temperatures for each month as well as extreme high and low temperatures for each month They will be indicated in either degrees Fahrenheit or Celsius depend ing on your choice of units in File Preferences At the bottom you ll see average monthly precipitation totals United States or precipitation days elsewhere The total height of a precipitation day bar is the total pre cipitatio
108. ion of geostrophic wind based solely on height contours Hitting the reset button replaces any entered value with the Earth s gravity constant Maps tab Note Make coastlines double wide is a setting that has been moved to Styles in Digital Atmosphere versions after 2002 General preferences E Topography use avg elev rather than max This controls what source of data is used when you select Map gt Make Topography When it is checked average elevation data is used When it is unchecked the maximum elevation data is used E Fill outer space When the map is zoomed out to where you can see the disc of the Earth the area outside the disc the outer space area will be filled with the general plot color if this option is selected E Label graticule When this is checked and the Map Features To Be Drawn gt Graticule is checked latitude longitude labels will be placed around the borders of the map The style used will be the lat Lat long graticule in Preferences gt Styles the font name and size will be obtained from this line Chapter Twelve PREFERENCES 85 E Draw graticule behind land masses Forces graticule to appear behind continental landmasses This is useful if the graticule is only wanted in the ocean areas E Plot legend on right hand side of map Forces the legend to the right hand side of the map JPEG image compression If you choose Map Export and choose JPEG as an image type the image will
109. ions when importing synoptic SYNOP data you can either round the reports to the nearest 3 hours making maximum use of off hour data or use no rounding ensuring sampling of the atmosphere at an exact moment It is generally best to use no round ing when possible This setting does not influence which SYNOP file is retrieved via the Internet it only controls how the resulting file is processed E View NEXRAD RCM rather than RAREP radar data This prevents two different radar formats from being mixed when you use Data gt Radar gt Echoes Check this box whenever you use NEXRAD RCM data such as that transmitted over EMWIN If you use the old SD RAREP code uncheck this box Chapter Twelve PREFERENCES 83 E Round AIREP reports within __ mb of a standard level Forecast ers like to see AIREP reports on upper air charts but AIREPs are rarely at an exact standard constant pressure level When this box is checked it allows AIREPs within a certain range of the active pres sure level to be included on the map Usually 25 mb is a good value When it is unchecked no AIREPs will be used unless they are at the exact pressure level that s active E Display highs and lows when plotting ASUS1 frontal bulletin This should usually be left unchecked When you produce a pressure analysis Digital Atmosphere will automatically plot highs and lows When you use it will plot its own sets of highs and lows which clashes with Digital Atmosph
110. isphere uses negative latitude Western hemisphere uses negative longitude Ingesting a scalar field When a simple scalar field such as temperature pressure wind speed etc is imported the value must be placed in the primary data value field and the secondary data value field must contain an asterisk character Ingesting a vector field If a numerical value is detected in the secondary data value field Digital Atmosphere will assume a vector field such as wind u v component is being ingested The primary data value must assume a direction rela tive to true north such as wind direction and the secondary data value must assume a magnitude such as wind speed When vector data mode is being used analysis calculations will use wind barb symbology to represent data elements Table plots Plots weather data from tables generated by third party sources Various weather agencies such as the Australian weather service generate lists of rainfall and temperature data Digital Atmosphere has the capability to import these based on the settings in the table template file DIGAT MOS TPL in your Digital Atmosphere directory A list of valid data types will be shown only if the most recent import operation has found data defined in the template file In the data file itself any table containing weather data should have each line of data corresponding to a geographical point and must have a lati tude longitude and anywhere from 1 t
111. it is the eyedropper icon pick up color If you hover over the 0 dBz level which is gray you should see it has R 90 G 89 B 90 We enter a line using this format LEVEL dbz red green blue threshold The red green and blue are self explanatory The dbz is the dBz level from the scale it s only used for color mapping If no scale is provided you can use 0 for weak echoes ranging up to 60 for heavy levels Finally threshold is a value used to accept pixels that are close to the required R G B values we will use 10 However it may be important to set this for JPG files where color drift may occur Threshold should usually be 10 but you can increase Appendix IMPORTING RADAR GRAPHICS 101 it to 50 or 100 if lossy JPGs are used and holes are appearing in the gen erated radar images Basically Digital Atmosphere looks at the numerical difference in red blue and green and adds up these differences using the absolute value to gauge the pixel against the threshold So if you define RGB 10 10 10 and the program sees a pixel with RGB 30 30 30 this adds up to a difference of 60 The pixel will be treated as part of your level definition as long as the threshold value doesn t exceed 60 When we are done defining all levels it will look like this TABLE 05 South African radar LEVEL 00 090 089 090 10 LEVEL 05 074 060 140 10 LEVEL 10 000 089 000 10 LEVEL 20 000 113 000 10 LEVEL 30 008 125 222 10 LEVEL 35 024 0
112. kets in the DIGATMOS FMT file for example if your database starts out with Joe s Data you should start out with this Joe s Data No database entries are read in until the start sequence is found Parameter list To actually read the data you will need to create a parameter list such as this TMP 4 148 Appendix TABULAR WEATHER DATA DWP 6 Each entry must be on its own line and the list ends when the end of the file is reached or another start sequence is found The example above in dicates that the temperature can be found in column 4 and the dewpoint can be found in column 6 Sample listing Here is a sample of an entry in DIGATMOS FMT which is used for Aus tralian Bureau of Meteorology AXF data synopData ICA 3 WMO 1 LAT 6 LON 7 ELE 9 TIM 5 DAT 4 TMP 22 DWP 23 WND 11 WNM 12 SKY 10 CIG 26 WXX 14 VIS 13 Valid parameters ICA xxx ICAO of the station for display purposes only WMOs xxx WMO number of the station for display purposes only LAT xxx Latitude in hundreds of degrees negative is southern hemi sphere LON xxx Longitude in hundreds of degrees negative is western hemi sphere LAX xxx Latitude in regular format negative is southern hemisphere LOX xxx Longitude in regular format negative is western hemisphere ELE xxx Elevation in meters used only for potential temperature calcu lations Appendix TABULAR WEATHER DATA 149 TIM xxx Time in UTC expressed as 450 fo
113. l Atmosphere is limited only by your imagination With the digital raster graphics supplied with Digital Atmosphere you can have moving maps suitable for storm chas ing or even activities that don t even have a meteorological purpose We ve added the functionality and it s up to you how you d like to use it Status The topmost menu selection is not a menu choice but is instead a readout of the GPS status It will show one of the following Idle The GPS device is not in use and has not been selected No comm port You have chosen a COM port that does not exist or use of this port is blocked because it is being used by another application No communication The port is open but the GPS is off or is not hooked up Communication A GPS has been sensed but no data is being read NMEA Valid data blocks have been read from the GPS device Start Instructs Digital Atmosphere to use the COM port and begin read ing GPS data You will need to determine which COM port the GPS is hooked up to Refer to your system setup documentation or use trial and error to find a valid port Stop Instructs Digital Atmosphere to cease using the COM port and discon tinue the reception of GPS data 76 Chapter Nine GPS MENU Recenter map automatically If enabled Digital Atmosphere will redraw the weather basemap when ever the current position is within 20 of the screen s edge Leave this unchecked if you want to have manual control
114. letins with only isobars GRAPHICS COMMANDS LOAD filename Loads a map IMPORTANT You must specify the dmf file in your file name e g c da20 bin mymap dmf The associated map will also be loaded SAVE filename Saves a map The filename parameter is the fully qualified filename with out the extension i e without bmp EXPORT filename Exports a map i e saves it to a variety of formats and without the accompanying atr file The filename parameter is the fully qualified Appendix SCHEDULER SCRIPTING 127 filename with a valid extension may be bmp gif jpg png pcx or tif Compressed TIFF saving is not available IMPORT filename Imports a map SOUNDING station Plots a sounding for the given station ERASE Erases all of the overlays on the map BLANK Erases the overlays as well as the basemap STAMP Imprints a timestamp at the top of the map that says GENERATED date time CLIP Copies the map to the clipboard GRADIENTCOLOR red blue green ph1 ph2 scale offset value Sets one of the File gt Preferences gt Misc gt settings to a particular value This allows the script to change a contour gradient scheme on the fly PROGRAMMING COMMANDS SET keywordnumber keyword Sets a specified keyword 1 through 9 to a certain value You can then use this keyword later on in the same script simply by placing the token x anywhere in the code where x is the keywordnumber This is useful
115. lly The possibilities are up to you Scripting basics To run a single script command Simply type in the script command in the command line on the scripts toolbar Hit return or click Enter and it will be processed Note that this does not run a script it just runs a script command A list of com mands is below To write a script Use any text editor or click on Create Script on the scripts toolbar and you can begin typing your script Note that scripts should use the file extension dsf in order to be properly recognized in Digital Atmosphere To comment out a line of code simply place a octothorpe colon or semicolon at the beginning of the line Commands are generally not case sensitive To run a script in run time Go to the scripts toolbar and select the Run Script button To run a script at startup Advanced users can run scripts on Digital Atmosphere startup by using standard command line parameters A space and the full name of the script file is simply appended after the filename at the command prompt or in the shortcut property for Digital Atmosphere To use the scheduler Go to the scripts toolbar and select the Scheduler button it will say Scheduler on or Scheduler off This will bring up a configuration window see below where the scheduler will coordinate which script files run at which time You must set Enable scheduler for the scheduler to take effect 124 A
116. lots and experienced meteorologists though they can clue you in on where significant weather is happening Cutting down on crowding We can easily change the density of station plots this to improve legibil ity or increase the information shown On the tool panel take the Data Plot Crowding slider and move it to 50 Now go to Map gt Erase map and choose Data gt Data Plots again You ll notice a lot of stations have disap peared The chart is much more legible but there is less information You can use the data plot crowding slider to control how many observa tions are shown Most meteorologists try to max out the setting without making the plots so crowded the data is unreadable Let s move the slider back where it was move the Data Plot Crowding slider to 80 Overlaying more contours Choose Analysis gt Temperature gt Temperature deg F Now choose Analysis gt Pressure Height gt Sea level pressure Nice You just added 6 Chapter One TUTORIAL the same field seen earlier on top of the map This illustrates how you can view different meteorological fields at the same time ee 7 YN UV Wolpe VENA 56 5 LARRE 46 44 azadgines4 S22 y 20 161200 3348 28g 5 P AA enak same S past bag 3 00 70 sai ation n Plats SFC 0249 a Gb ln F AZ ER z ai NG 16an cabo lpi 2078 248 474 Temperat AIE URMAT 6 Ei Wanha Graphs stan 2 Xe3 8C250f 70 7215787 68 Seeing the wind flow It is possible to visualize t
117. magnitude by using CONT WSPD contour windspeed or using a vector to magnitude function which has not been provided yet 3 The active level is always taken from the Active Level setting on the toolbar It can be overridden using a Setup command The same is true for data Time settings 4 Multiple fields are handled by using the output form to write a field to a slot such as STOR 5 to store the result in slot 5 Various transforma tions which depend on a field number such as SDIF scalar difference are supplied with two field slots with which to read 5 Commands can be strung together to produce multiple fields Cur rently there is a limit of 255 characters to a script command 6 Suggestions for transformation commands output commands operators and so forth are greatly welcomed at this time Much more is planned this is only a start For an idea of what is possible see the PC GRIDDS documentation at http www lib noaa gov pcgridds appendix html C 7 Scripts are not case sensitive Examples CONT CINT 4 SLPR Explanation Take the sea level pressure field Set the contour interval to 4 Now contour it Note that the color is not set so the result color is unpredictable Also the level is not set so if the current height setting is 500 mb an invalid fieldwill result DATA VKNT WSPD Explanation Take the wind speed field which will be in m s Convert it to knots Now view it as a numerical grid CONT CINT 6
118. n a line This arc is actually the shortest distance between the two points and it just appears as an arc because of the map projection distortion Looking at station plots Station plots are little packets of data that appear on the map at vari ous locations showing the actual observed conditions at that location Plotting them in Digital Atmosphere is a snap Just click on Data gt Data plots Instantly the map is filled with a smorgasbord of information Chapter One TUTORIAL 5 82 143 The station plot above indicates a temperature of 82 degrees and a dew point of 53 degrees dewpoint is proportional to moisture Winds are blowing from the southeast at 5 kt as the wind barb always points into the wind The sky is 50 covered with cloud The sea level pressure is 1014 3 mb The numbers that make up the sea level pressure figure are in tens units and tenths this value is then prefixed with either 900 or 1000 whichever brings the value closest to 1000 mb So 450 45 0 1045 0 mb while 550 55 0 955 0 mb In the center circle the amount of shading is proportional to the amount of clouds You ll also note that some stations have a square this means the observation was made by a computerized station Some stations might have a red color this means bad IFR weather while some are blue which means marginal MVFR weather The coloring is determined strictly by visibility and cloud height and is more for the use of pi
119. n days during a given month The part in gray is how many of those days are composed of snow days and the part in red is how many are composed of thunderstorm days 72 Chapter Eight CLIMATOLOGY MENU Hurricane tracks Digital Atmosphere offers a database of historical hurricane tracks taken every six hours for storms that occurred in the East Pacific and Atlan tic basins from 1850 to 2002 The tracks will be displayed on the active workchart Year Use the range boxes to display data for a certain time period To display data for only one year enter the same year in both boxes Line width Enter a number here to control the width of the lines that will be plotted The recommended value of 4 should be used Plot storm name at origin Plots a label containing the storm s name at the beginning of the track Plot date labels along track Plots dates and times along the length of each storm track Color code for wind speed Changes the line color of the previous seg ment based on the sustained wind speed at that time The values are Gray 0 34 kt tropical depression Black 35 63 kt tropical storm Green 64 83 kt hurricane Saffir Simpson 1 Yellow 84 95 kt Saffir Simpson 2 Red 96 113 kt Saffir Simpson 3 Purple 114 134 kt Saffir Simpson 4 Blue 135 kt Saffir Simpson 5 The source of the data is the NHC HURDAT tables at http www nhc noaa gov pastall shtml The tables are provided in Digital Atmosphere verbatim
120. name convention The legacy filename format for NWS GRIB data is as follows Some da tasets can still be found in the top level directory at http weather noaa gov pub which use this filename convention Sample us008_gf000_02020300_HxXAx Portions us008_gfMMM_YYMMDDHH_ADGT Here is what each field means MMM Model code Underlined codes are in current use as of Feb ruary 2002 others are obsolete and are listed only for historical purposes 000 Experimental 010 GlobalWindWave 039 NGM 044 SeaSfc Temp 076 MRFbiascorrected 077 AV Nfcst 078 MRF 080 MRF 081 AVNinit 082 MRFinit 083 ETA80km 084 ETA22km 085 ETA29km 086 RUC60km 089 ETA48km 094 MRF T170 L42 096 AVNfcst T170 L42 121 WesternNorthAtlanticwavemodel 122 AlaskaWatersRegWaveModel 130 MergeOfRucEtaSpectral YYMMDODHH Year month date and hour of model start time A GRIB designator H WAFS Family Of Services Y AWIPS Z AWIPS D Data type X mixture G Grid A 201 Nhem PS H 213 US PS 1 202 US PS J 203 Alaska PS K 204 Hawaii MER L 205 PuertoRico PS M 206 CentralUS LAM N 207 Alaska PS O 208 Hawaii MER P 210 PuertoRico MER Q 211 US LAM R 212 US LAM T 214 Alaska PS U 215 US LAM V 216 Alaska PS X experimental Code following the geographical area means PS Polar Stereographic LAM Lambert Conformal MER Mercator Appendix GRIB DATA 121 T Timestamp A 00 B 06 C 12 D 18 E 24 F 30 G 36 H 42 I 48
121. nd rapidly expand ing capabilities will let you monitor developing weather anywhere on Earth around the globe or right in your own local area Digital Atmosphere is essentially a geographical display program that ingests raw weather bulletins disseminated by the National Weather Service to Internet sites satellite feeds and weather databases Using this data it produces stunning plots and analyses that are equivalent to those found on multi million dollar workstations The maps and other products you create with Digital Atmosphere are fully customizable You can define the geographic area you wish to map and specify the map s resolution You decide how much detail you want shown in your maps from country borders only to rendered topography with county lines and roads overlaid You choose what weather data you want displayed how the data is displayed and in many cases what algorithms are used to analyze the data Whatever your meteorological graphics needs Digital At mosphere can create exactly the map you desire using only the parameters you desire DIGITAL ATMOSPHERE SPECIFICATIONS Data formats supported Land synoptic WMO FM 12 SYNOP Ship synoptic WMO FM 13 SHIP METAR WMO FM 15 METAR Buoy WMO FM 18 BUOY Upper air WMO FM 35 TEMP Aircraft data report ACARS WMO FM 42 AMDAR NMC frontal depiction transmission format ASUS1 KWBC FLEET code WMO FM 45 46 Gridded binary GRIB WMO FM 92 IX
122. nergy and negative values as being associated with energy coming back the other Way 0 5 deg Shows velocity from scan elevation 1 tilted 0 5 deg from the ground 1 5 deg Shows velocity from scan elevation 2 tilted 1 5 deg from the ground 2 4 deg Shows velocity from scan elevation 3 tilted 2 4 deg from the ground 3 4 deg Shows velocity from scan elevation 4 tilted 3 4 deg from the ground Short 32 nm 0 5 deg Surprisingly the radar generates a close range velocity product with a gate resolution of only 790 feet You can view this product here for look ing at storms up close SRM 0 5 deg Shows storm relative mean radial velocity from scan elevation 1 tilted 0 5 deg from the ground The storm relative mean radial velocity SRM product is essentially the same as base velocity but removes the com ponent of the storm s motion allowing velocity signatures to be more accurately analyzed This product is preferable to the standard velocity products for storm forecasting The source for the storm motion compo nent is usually the average motion of all storms detected by the radar s SCIT storm tracking algorithm SRM 1 5 deg Shows storm relative mean radial velocity from scan elevation 2 tilted 1 5 deg from the ground SRM 2 4 deg Shows storm relative mean radial velocity from scan elevation 3 tilted 2 4 deg from the ground 68 Chapter Seven RADAR MENU SRM 3 4 deg Shows storm relative mean radial
123. netary map A planetary map is a popular name for a graphic image that covers from 180 to 180 degrees longitude from left to right and 90 to 90 degrees latitude from north to south It may come in many different scales and resolutions but the important thing is that it covers the entire world It Chapter Four MAP MENU 37 is a relatively simple procedure for Digital Atmosphere to map the globe using such a graphic To find a planetary map we suggest putting this into a search engine especially an image one like Google Images earth texture Some sources include http planetpixelemporium com earth html http arstechnica com reviews 4q00 macosx pb1 macos x beta 12 html http www oera net How2 TextureMaps2 htm Planetary maps that are 1440 x 720 will have a resolution of 0 25 deg 15 miles which will offer marginal quality for synoptic scale charts Extremely large maps exceeding 10 000 pixels in any dimension may ex ceed available memory and cause an error It may be helpful to find im ages that are not in JPG format as sometimes the compression artifacts cause degradation of the image We also suggest finding bright maps as dark maps are common but make it hard to read data annotations and contours It may be helpful to bring dark maps into a graphics program to lighten them up Note that when a planetary map loads Digital Atmosphere will not au tomatically replot the basemap If you wish to do this select Map gt Ad
124. nts BASEMAP Plots the basemap Appendix SCHEDULER SCRIPTING 129 CITY Plots cities COOUT Plots county outlines CONAME Plots county names HIGHWAY Plots Interstate highways U S only ROAD Plots major roads U S only CUSTOM Plots custom overlays REMOVE Removes the last product from the display DEPRECATED COMMANDS These commands are not supported in the Equinox version and beyond CENTER station zoom width height Makes a map with the chosen station in the center of the screen Zoom is a value equal to 3964 x where x is the width of the map in statute miles Width and height are the map sizes in pixels ARCHIVE cddriveletter yymm yymmddhh Accesses data from the Weather Graphics Technologies Surface Archives or Upper Archives CD ROM The cddriveletter parameter is the drive letter while yymm is the year and month full four digits and yymmd dhh is the year month date and hour full eight digits Caution This command has not been fully tested and may not work GRADIENT on of f Turns on or turns off the File gt Preferences gt Contours gt option ISOPLETH on of f Turns on or turns off the File gt Preferences gt Contours gt option 130 Appendix SCHEDULER SCRIPTING Valid product types For a list of valid codes see the appendix showing Valid Product Types Sample scripts This script downloads synoptic data from Albany imports it displays plots and sea level pres
125. o 50 data values for that point Template file entries DEF starts the definition of a table Give the table a name in T1 this name is used for display purposes Chapter Five DATA MENU 49 LEG defines a line that can be used as a legend for the table such as a line that contains a date or valid time Specify a keyword that is to be located on the line When encountered it will be used in legends FLG is a scrap of text which when encountered during importing tells Digital Atmosphere that it is about to encounter a table This flag must be encountered before any data can be imported Specify the scrap of text in T1 BEG is a scrap of text which when encountered during importing tells Digital Atmosphere that a data table is starting right now Put the scrap in T1 and define the column where it must be seen in V1 and the length of the scrap in V2 Data import always ends on an empty line DAT is specified for each data element that appears on a line Give the field a name in T1 this is used only for display purposes Define the beginning column of the data in V1 and the length of the data in V2 MIS specifies characters that are used to denote missing data LAT specifies where the latitude decimal only is found Put the col umn start position in V1 and the field length in V2 LON is similar to LAT but for longitude Example DEF Australian rainfall data LEG Observations FLG IDCLRD00001 BEG 6
126. og similar to this one RE HWS NCEP ETA12 00HR MSL Pressure ETA reduction Pa NWS NCEP ETA12 OOHR MSL Pressure Pa NWS NCEP ETA12 OOHR 250 MB Absolute vorticity s INWS NCEP ETA12 OOHR 500 MB Absolute vorticity s INWS AICEP ETA12 OOHR 700 MB Absolute vorticity s NWS NCEP ETA12 OOHR 850 MB Absolute vorticity s NWS NCEP ETA12 OOHR 1000 MB Absolute vorticity s NWS NCEP ETA12 OOHR GROUND Pressure Pa NWS NCEP ETA12 OO0HR GROUND Geopotential height m NWS NCEP ETA12 OOHR 2 M AGL Temperature K NWS NCEP ETA12 OOHR 2 M AGL Relative humidity HWS NCEP ETA12 OOHR 10 M AGL Wind u component kt NWS HCEP ETA12 OOHR 10 M AGL Wind v component kt gt AGC AIC EPRI amm nmam matat muaonimitatinn Meee fmt Select a GRIB record that you want to view Choosing any wind component will cause the full wind field to be imported X Cancel Help You must then choose which field you want to see The specific field you chose will be extracted To view the field click on either Contour or Plot in the Toolbox window see illustration For full information see the chapter GRIB Data Chapter Three FILE MENU 19 OOUUUUUUUUUUU UULU LULUH LLULLU UULU UUU UULU LULL hdd UUU UUL LUULU UULU UU LUULU OUUU UUU UULUUIUUUIRX NOTICE Because of the complexity of GRIB data and the fact that it is not fully supported by Digital Atmosphere yet Weather Graphics Technologies will not provide assistance in locating retrie
127. oject it is superfluous Adjusted digatmos nex to put clear air mode on the same palette as pre cipitation mode to allow for a standardized mosaic Entering for a color in digatmos nex keeps that color level from plotting This can be used to allow for a unified mosaic color scheme Added code to prevent Digital Atmosphere from generating zero value serial numbers Added handling for METAR unknown precipitation UP This will plot as two solidii and will carry weather code 100 I saw lots of UP reports from Texas during the January 15 2007 sleet event UP is most likely sleet 162 Appendix VERSION CHANGE SUMMARIES Changes made to WSR 88D plotting module to allow various raster data most notably Composite Reflectivity to plot correctly The module now determines polygon positioning based on the number of rows in the raster table as well as the resolution for the product as defined in digatmos nxc Also added progress bar updating on raster data In Radar gt product logic is added to detect and discard old radar scans so as not to mess up mosaics An RPG product that is more than 15 minutes older than the preceding RPG products being plotted will be discarded and a message will appear in the status window showing it was discarded The weakness is if the plotted site is the very first to be plotted it will be used since no other comparisions are avail able A tutorial has been added for the Radar gt Import Image
128. on of the parameter for that row It cannot be modified E R G B These are color codes which must be a whole number be tween 0 and 255 The R column is for red G is for green and B is for blue To pick orange for example you would set R to 255 G to 128 and B to 0 You do not need to use these columns A vastly simpler input is available simply by clicking on the color swatch to the right of the R G and B columns If you do wish to enter R G and B values the following resource may help http www cloford com resources colours namedcol htm Do not enter hex hexadecimal values they will not be recognized E Color swatch Click on the color swatch to select a different color In the popup window a crosshair will show the current color value Move it around or change the values to pick a new color The value of R G and B will be filled in automatically for you 90 Chapter Twelve PREFERENCES E Contour type Indicates the purpose of this contour It cannot be modified E Unit Proper entries are as follows Do not mixmatch units or the program will ignore the setting and use a default unit Units marked with cannot be changed Temperature deg f deg c deg k Moisture g kg Relative Humidity percent Horizontal Velocity knots mph m s Vertical Velocity ub s microbars per second Height meters Pressure mb hpa kpa inches Precipitation Totals inc
129. on point f are used to produce a weighted average for f NOTE If the user has selected automated station spacing then a a 1 333 The source of this analysis scheme is not known at this time The algorithm operates by iterating through all 900 gridpoints x y At each gridpoint each observation f is examined Only those observations whose distance is less than a from x y are considered A distance de pendent weighting coefficient is calculated for each observation f The value dk is the distance between gridpoint f and observation f in units of a therefore d a 0 1 It can be seen that the negative w term forces the expected inverse oe of distance to weight fy S k 1 n f w S k 1 n w where w a d a 4 2 k Barnes analysis The Barnes analysis scheme Barnes 1964 is considered to be a refine ment of the Cressman method It uses a one pass scheme rather than successive iterations to achieve convergence of the analysis field NOTE Appendix ANALYSIS THEORY 143 If automatic smoothing is enabled the average station spacing value is set toa a 1 333 Only observations which fall within a rather large area of influence a are considered The value d is the distance between gridpoint f and observation f in units of a therefore dJa 0 1 The distance dependent weighting coefficient and the summation to produce a first guess of grid point data value fa are as follows fy S
130. or the great circle track the initial bearing from the starting point and the distances in nautical miles statute normal miles and kilometers Special note If you want to see distance and direction from cities close to the cursor see Map gt Cursor City Distance to get a display of this information The path data will be replaced by the city information whenever Map gt Cur sor City Distance is enabled 16 CHAPTER 3 File menu These menu commands are reserved for functions that operate on data files or are significant to Digital Atmosphere s operation Update all workcharts Causes the contents of each open workchart to be updated with the cur rent product As of 2007 this command is still being tested and is not guaranteed to work properly New Workchart Causes a new workchart a separate map to be spawned Import Directory Specific File Digital Atmosphere is a tool that lets you create weather charts using current raw data Therefore you need to get raw data into Digital At mosphere We refer to this process as raw data import Once you import data into Digital Atmosphere via any of the possible methods explained below the program will continue to work only with that data until you perform another import In other words the data will still be in Digital Atmosphere if you exit from the program and then run it again later Once you perform a second import all the data from the first import is deleted
131. ore using this command Be aware that the data from a shapefile is treated as an overlay To use it as a permanent graphic in your workcharts you must use Map gt Copy Markings Onto Basemap after displaying it Shapefile attribute selection If an attribute dbf file was paired with your shapefile you will see a popup screen that looks like this Shapefile attribute selection f lol x Field to display as text icone M Jf OK Help The meanings are as follows 32 Chapter Four MAP MENU Field to display as text This dialog allows you to select a text field of each feature such as a forecast office name etc to be displayed as text Select which field you want displayed To ignore this such as if you re just drawing boundaries just leave all fields set to none Longitude source You may also select an optional latitude longi tude source if the data explicitly contains a Latitude and Longitude field not all of them do If you are certain that there is a Latitude Longitude field in the dataset you may choose them Otherwise leave them set to none and the text will be displayed either on the last point plotted or in the middle of the polygon or polyline bound ing region Tips Here are some valuable tips for working with shapefiles E If you don t want to pick an attribute every time you display a shape file you may delete or rename the associated dbf file so that it is not detect
132. orm Storm Storm Storm relative relative relative relative Clutter filter velocity 0 5 deg velocity 1 5 deg velocity 2 4 deg velocity 3 4 deg 116 117 APPENDIX GRIB data Because of the complexity of GRIB data and the fact that it is not fully sup ported by Digital Atmosphere yet Weather Graphics Technologies will not provide assistance in locating retrieving or using GRIB data Itis provided as is Comments are welcomed but we may not be able to respond to ques tions If you need help please access our public discussion group on our website at www weathergraphics com Grid definition file Advanced users can edit the digatmos grd file to change the grid model and parameter definitions The MODEL section defines a model name based on its model number Column 1 3 and IDENTIFIER of the facility Column 5 8 see IDENTI FIER section The CENTRE section defines a production facility The FIELD section defines a product based on its parameter number Column 1 3 and the IDENTIFIER of the facility Column 5 8 see IDEN TIFIER section Based on what appears here Digital Atmosphere selects the Preferences Style type Column 25 27 to display this field Fixing GRIB problems There are two symptoms which indicate a problem with GRIB data E When question marks appear in the field panel e g 72HR 500 MB ECMWF CREATED 29DEC06 12002 E When corrupt output or no output can be generated on the screen
133. ove away But what if the temperature 200 miles on each side is instead 52 deg F With Death Valley being at 96 this would appear on your graph as a short upward spike at the location corresponding to Death Valley These are two unique mathematical waves the first one with gradual rises and falls means that the temperature field is composed of large or long wavelength features The latter situation with sharp spikes and dips means that the temperature field is composed of short or small wavelength features As you can see gradual changes mean that the meteorological field has long wavelength characteristics and sharp local ized changes imply small wavelength features Digital Atmosphere uses a 30 x 30 mesh grid to sample these condi tions The mesh is like lines that are drawn across the map 30 across and 30 down to sample the wave structure that is present in the type of analysis you pick Using equally spaced grid points is the easiest way to perform computerized analysis calculations Digital Atmosphere must find where reporting stations are within the grid and try to map the val ues to that grid taking into consideration how far the reporting station is from a gridpoint and figuring out what to do with gridpoints that aren t assigned any data This is what takes up the majority of processing time So why not just map values to the grids and interpolate between all the points Digital Atmosphere s nearest neighbor te
134. past hour The highest reportable total is 15 inches The radius of coverage is 124 nm with a resolution of 1 1 nm Storm tracking information STI This product shows information provided by the radar s Storm Cell Interpretation and Tracking SCIT algorithm It shows past current and future location of identified storm cells Past locations are shown for each volume scan this is an interval of 5 minutes in VCP11 and 6 minutes in VCP21 Future locations are identified at 15 30 45 and 60 minutes in the future though these intervals are customizable by the radar site operator Each storm has a unique ID of two characters ranging from AO to Z9 and is recycled when past AO when no storms have occurred in a certain number of volume scans the ID is reset to AO The storm data has a radius of coverage of 248 nm Clutter control filter CFC Shows the clutter filter notch and bypass maps as a radial image The levels are coded as follows 0 disable filter 1 no clutter filter 2 5 low clutter filter 3 6 medium clutter filter 4 7 high clutter filter Codes 1 to 4 specify the map is bypassed by CTRL while 5 7 force the filter to oper ate The product has a radius of coverage of 124 nm with a resolution of 1 km and 1 4 deg azimuth 71 CHAPTER 8 Climatology menu Digital Atmosphere maintains a database of numerous monthly weather parameters for over 2 000 weather stations across the world Most of this archive spans a 30 year time per
135. pecific commands by right clicking on the map This action defines a location When you do this a popup menu will appear and you will have the following options that apply to the workchart or the defined location Cursor slaving Recenter map Marks 14 Chapter Two DISPLAY COMPONENTS Cursor slaving This causes slave cursors to appear on all available workcharts which are centered on the same geographical position as the position being indicat ed by the cursor This is useful for comparing features on different types of radar products You may turn cursor slaving on and off It is best to leave it off when not in use 17 592 Mon 28 May 07 Graphic showing a slaved cursor between two charts Recenter map This is the only popup menu function that currently exists It will cause the basemap to be redrawn centered at the location you have selected To refine this further you may use the Zoom In or Zoom Out speed but tons or use Map gt Generate Marks This allows you to define reference marks on the map to be recalled later at any time Use Set mark to define a new mark Use Draw mark to draw all marks in memory Use Clear memory to erase all defined marks from memory Distance and track cursor Digital Atmosphere has a sophisticated interface for measuring dis tances Simply drag the mouse hold down the left mouse button at your desired start point and move the cursor across the screen You will
136. ponents 7 Main menu 7 Speed buttons 7 Toolbox 9 Status box 12 Workchart 13 Popup menus 13 Distance and track cursor 13 File menu 15 New Workchart 15 Import Directory Specific File 15 Import GRIB 15 Clear data directory 17 Set font mode 17 Get archived data 19 Quality control 19 View raw data 21 Print 22 Print setup 22 Calculator 22 Recompile tables 23 Preferences 23 Exit 23 Map menu 25 Erase map 25 Load basemap 25 Save basemap 25 Generate basemap 26 Blank map 28 Import map from file url 28 Import shapefile 29 Copy markings onto basemap 31 Copy chart to clipboard 32 Export chart 32 Cursor city distance 33 Information 33 Set comment 34 Make topography 34 Import planetary map 34 Add overlay 35 Annotations 38 Data menu 41 Retrieve data 41 Data plots 44 Custom data plots 45 Table plots 46 Television plots 47 Warnings 48 Frontal depiction 48 Fleetcode 50 Sferics 51 Convective outlooks 52 Hurricane tracks 53 Troubleshoot data 54 Soundings 54 Extract model data 54 Analysis menu 57 Edit analysis scripts 57 How analysis works 57 Radar menu 61 View radar data 62 Load radar data 63 Save radar data 63 Import radar data 63 Set NEXRAD station 64 Quick pick 64 Set date time 65 Base reflectivity 65 Reflectivity 66 Velocity 66 Spectrum width 68
137. ppendix SCHEDULER SCRIPTING When the scheduler is no longer wanted bring up this window again and unset Enable scheduler To specify the execution time for each script write the execution time in 4 digit UTC time in hhmm format i e 7 45 am is 0745 and 2 15 pm is 1415 followed by a space and the name of the file including its dsf extension Be sure to specify the full pathname of the file otherwise Digital Atmo sphere will assume it is located in your Digital Atmosphere directory There can be an unlimited number of scripts and execution times in this list Advanced users You can edit or swap out this schedule list if you wish it s located in the Digital Atmosphere directory under digatmos sft Valid script commands DATA DISPLAY COMMANDS PRODUCT type level title Overlays a meteorological product on the map The appropriate data must have already been imported Valid type parameters are document ed at the end of this section Levels are specified as follows for surface data the level is 0 zero for millibar levels the level equals the millibar level 500 etc and for FT height levels the level equals the ten thou sands and thousands digits multiplied by 1 so 34 000 ft equals 34 The title parameter is optional and contains a text title that will be placed in the legend Derived fields are not supported at this time ANALYZE scriptstring Performs an analysis using an analysis script command For in
138. r and minute value respectively If the difference is more than 10 minutes check your Windows time and time zone settings 5 Click Retrieve Weather data will be retrieved from the College of Du Page server and will then be decoded and imported This will take about 20 seconds on most computers If any errors occur when retrieving the data such as file not found or other server errors chose a different METAR source in Step 2 Chapter One TUTORIAL 3 Make sure we re at the surface We want to make sure we re looking at data at the surface so view the toolbar at the top left and make sure Active Level shows Surface Digital Atmosphere usually starts with this set to Surface and no adjustment is required Looking at the big picture Meteorologists usually like to get their first look at a weather chart using isobars lines of equal pressure To display these choose Analysis gt Pressure gt Sea level pressure Congratulations You ve made your first weather map and it was incredibly easy It may look something like this evel Pressure SFC 0150 02492 Sat 26 May 07 Adjusting the map amp adding content Let s create a new map and add some details 1 Right click on the center of Minnesota and choose Recenter Map A new map draws centered on Minnesota When you see GENERATE Map completed in the status window at the lower left you are ready to continue 4 Chapter One TUTORIAL 2 Click Map
139. r 4h50m and 1629 for 16h29m DAT xxx Day of month expressed as 16 for September 16 TMP xxx Temperature in degrees Celsius DWP xxx Dewpoint in degrees Celsius WND xxx Wind direction in degrees true WNS xxx Wind speed in knots WNM xxx Wind speed in meters second SKY xxx Total sky cover in oktas 9 obscured 10 not available SLP xxx Sea level pressure in millibars lt FONT face Courier gt CIG xxx Ceiling in hundreds of feet WXX xxx Weather code first and second digit equals ww weather code e g 61 is light rain VIS xxx Visibility in meters P01 xxx Precipitation total in millimeters past 1 hr P06 xxx Precipitation total in millimeters past 6 hr P12 xxx Precipitation total in millimeters past 12 hr P24 xxx Precipitation total in millimeters past 24 hr PXX xxx Precipitation total in millimeters source defined period un known to Digital Atmosphere PCP xxx Precipitation total in millimeters PCT xxx Precipitation time period in hours PTR x Pressure trend equals a in app group PTN xxx Pressure tendency in tens of millibars SNO xxx Snow depth in centimeters CLL x Low cloud code CLM x Middle cloud code CLH x High cloud code MAX xxx Maximum temperature in degrees Celsius MIN xxx Minimum temperature in degrees Celsius More on Australian AXF data Information on Australian AXF data can be found here http www bom gov au nmoc Obs IDY03000 doc http www bom gov au nmoc Obs IDY03090 doc http ww
140. r are being omitted by the data provider The source of all station reference information is the Digital Atmosphere station file digatmos stn The control menu in which you may select types of sta tions as well as the general appearance appears as shown below E Plotted symbol This is fairly self explanatory The mark on top of each weather station may be drawn as a square circle triangle a hollow form of these a cross or a user defined character such as the letter X The color and width of all marks are controlled in File gt Preferences gt Styles under the stl station reference lines row E Size of symbols Controls how small or how large the symbol mark will be plotted A value of 3 is recommended for most purpos es You should change this when plotting extra large or extra small maps E Label 1 and Label 2 Digital Atmosphere can plot a text label next to each station symbol This can contain the ICAO 4 letter alphabeti cal code the WMO 5 digit numeric code or the station name The 40 font used for labels is controlled in File gt Preferences gt Styles under the stt station reference text row Category You may want to plot only radar sites or only upper air sites If these are annotated as such in the digatmos stn file they can be plotted E Filter according to station status The station lists do contain sta tions which have been flagged as obsolete which is done when an equal sign is
141. rce bulletin needs to be the NHC forecast advisory or JTWC warning with coordinates and forecast positions They can be auto matically downloaded via the Internet gt Retrieve panel If there is any problem with a bulletin not plotting it may be due to an error in the way the bulletin is written Decoding these bulletins into machine readable format is not always error free Currently there is no support for bulletins from other global hurricane centers Technical information The import module locates hurricane bulletins based on the National Hurricane Center header KNHC or the Joint Typhoon Warning Center Chapter Five DATA MENU 57 header and saves them to the queue hur holding file When Data gt Hur ricane Tracks is requested the hurricane module reads queue hur and displays any available bulletins Here is a sample of a hurricane track bulletin WTNT22 KNHC 060837 TCMAT2 TROPICAL DEPRESSION LARRY FORECAST ADVISORY NUMBER 19 NWS TPC NATIONAL HURRICANE CENTER MIAMI FL AL172003 0900Z MON OCT 06 2003 TROPICAL DEPRESSION CENTER LOCATED NEAR 17 3N 94 0W AT 06 0900Z POSITION ACCURATE WITHIN 50 NM PRESENT MOVEMENT TOWARD THE SOUTH SOUTHWEST OR 200 DEGREES AT 3 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB MAX SUSTAINED WINDS 20 KT WITH GUSTS TO 25 KT DISSIPATING 12 FT SEAS ONE OSE OSW 100NW WINDS AND SEAS VARY GREATLY IN EACH QUADRANT RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADR
142. rces of data consist only of the ASUS1 KWBC numerical text bulletin produced by the National Weather Service This bulletin must have been imported and found with its headers intact before it can be plotted The bulletin is usually found on Unidata servers under data sur face front or a similar directory or by the bulletin header name itself A couple of links are provided in Digital Atmosphere s Internet gt Retrieve Data window which should be used if possible Note that the presence of this bulletin does not imply thatMaking your own maps By using the Create or Append options above you can create your own frontal depic tion maps To pull up the drawing commands simply right click on the map and choose frontal depiction tools You will see a menu like the one below Sample of ASUS bulletin If your frontal depiction does not deliver the correct results you can go in and hand edit this bulletin in QUEUE FRT using any text editor 515 ASUS1 KWBC 111919 CODSUS VALID 111118Z HIGHS 1030 41165 1030 38154 1027 45135 1025 31138 1035 6143 1022 3730 1033 5589 1030 6286 LOWS 979 46169 1017 38139 997 4257 997 3865 980 63172 987 66144 998 75113 1005 36102 1013 35112 998 7168 OCFNT WK 46169 46170 45171 COLD WK 45171 44170 42169 40169 40169 39168 52 Chapter Five DATA MENU WARM WK 45171 46172 47174 46178 COLD WK 38139 36140 33144 31149 31153 STNRY WK 4418 4525 4531 4741 4748 4653 4457 4160 TROF 4257 4151 3647 3145 28
143. re some basic mathematical knowledge The colors are defined according to the plotted Value for the particular point on the map which will always be in the range 0 1 where 0 is the lowest possible reading and 1 is the highest possible read ing This Value is fitted to a sine wave according to user defined param eters to determine the Red Green and Blue component of its color See the Appendix on Color Gradients for more information Planetary maps For more information on planetary maps see the Map Menu chapter E Smooth final image Applies a simple Haltiner smooth to graphics imported in the Maps gt Import Planetary Map function E Re overlay geography By default Digital Atmosphere does not over lay map data on a Maps gt Import Planetary Map operation Check this if you want the basemap to be drawn automatically 92 Chapter Twelve PREFERENCES For USGS DEM purposes only This allows the import to stop or start if the text value shown in this box exists in the raw data on the same line where KWBC is found To have any effect a text entry of at least 4 characters must be made If KWBC and the string is found then import begins If KWBC is found and this string is not found on the line then import ceases It was used to allow the USGS to selectively process archived NOAAPORT data A date time text entry can be placed here and various sets of data can be accepted or rejected based on the value Special diagnostics T
144. red radar source override When radar products are selected for download Digital Atmosphere uses a predefined set of Internet URLs Use this to switch sources This can come in handy if the server is down This setting is also used for retrieving archived radar data to use special URL sets see Radar chapter E Preferred radar color override When radar products are viewed Digital Atmosphere uses a predefined color scheme for displaying the data Use this to switch color schemes Print settings E Color assignment Normally this is set to Palette and should be left at that setting Use the RGB setting if you have problems with print contrasts or colors For advanced users the Palette setting uses WinAPI calls to DIB_PAL_COLORS while RGB uses DIB_RGB_COL ORS Meteorological tab Checkboxes section E Geopotential heights in full meters only The geopotential height on upper level charts are commonly plotted in decameters dam When this box is checked contour labels and upper plot models will appear in full meters When it is unchecked the labels and plot models will switch to conventional shortening typically used by meteorologists see table below The default setting is unchecked Conventional shortening is as follows 100 to 500 mb undreds tens and units of decameters are displayed 501 to 1000 mb hundreds tens and units of meters are displayed E Round synoptic reports to nearest 3 hours when importing You have two opt
145. ries tend to be bona fide weather offices rather than control towers or flight service stations Upper air data from balloon launches is taken worldwide twice a day It is transmitted in TEMP format also known as TTAA TTBB PPBB for mat and radiosonde format This format uses extensive numerical cod ing Availability of upper air data is fairly good across much of the northern hemisphere but is seriously lacking in the southern hemisphere where satel lite based sensors are widely used to initialize computer model forecasts Since much of this data is freely available from a variety of sources Digital Atmosphere gives users a flexible tool for graphically importing and display ing all of the different weather data formats provided by the GTS 157 APPENDIX Raw data samples Listed here are some examples of what kinds of data will be imported by Digital Atmosphere depending on your checkmarks on the status panel You can refer to these examples if you have any trouble getting Digital Atmo sphere to read something or are unsure of what a particular product or bul letin should look like Airways SAO data This is the backbone of weather observation code in the United States and Canada It is issued hourly from thousands of weather stations A sample report will look like this JFK SA 1150 250 SCT 7 113 44 21 2513 989 SD RAREP radar reports Also called hourly radar reports RAREPS and SD reports
146. riod Wave height Wave instrument measured height Wind wave period Wind wave height Primary swell direction Secondary swell direction Primary swell period Primary swell height Secondary swell period Secondary swell height MVFR IFR weather SPC Convective Outlook Day 1 SPC Convective Outlook Day 2 Surface 6000 ft shear not completed Lifted condensation level not completed CAPE not completed CIN not completed not used not used not used not used not used RADAR PRODUCTS Radar product codes All ranges 128 nm unless otherwise noted Base reflectivity BREF1 Base reflectivity 0 5 deg BREF2 Base reflectivity 1 5 deg BREF3 Base reflectivity 2 4 deg BREF4 Base reflectivity 3 4 deg BR248 Base reflectivity 0 5 deg 248 nm Base velocity BV32 Base velocity 0 5 deg 32 nm BVEL1 Base velocity 0 5 deg BVEL2 Base velocity 1 5 deg BVEL3 Base velocity 2 BVEL4 Base velocity 3 deg 4 4 deg Base spectrum width SW SW32 Spectrum width Spectrum width 32 nm Appendix FIELD AND PRODUCT CODES Derived products Composite reflectivity Composite reflectivity 248 nm Echo tops Severe weather probability Vertically integrated liquid CR CR248 ET SWP VIL STI H TVS M OHP THP STP SRMV1 SRMV2 SRMV3 SRMV4 CFC Storm tracking Hail detection Tornado vortex signature Mesocyclone One hour precipitation Three hour precipitation total precipitation Storm St
147. ripting panel Each will be described below DATA PLOT CROWDING 81 crowded m CLOCK a a Workchart tab Active level This controls the current level It should be set to Surface except when viewing upper air data Time selection This controls how the valid time for surface data and upper air data are chosen Digital Atmosphere will choose the most popular time rounded to the time quan tity selected So if all data is valid for 1600 UTC except for one observation valid at 1533 UTC the latter observation will be included if a 1 hour rounding is selected and dis carded if 20 minutes is selected If you wish to override time selection you can choose manual to be prompted for a time each time you generate a product or you can choose a specific numerical time Data plot crowding Controls how many station plots appear on the map when you select Data gt Data plots Slide to the left for fewer station plots or slide to the right for more or click All which sets the slider to 100 Clock Shows the local date time LOC and the Greenwich Mean Time date time UTC These are taken from your Windows time 10 Chapter Two DISPLAY COMPONENTS settings If they look erroneous it is not a problem in Digital Atmo sphere From your Windows start bar go to Start gt Settings gt Control Panel gt Date Time and make sure the correct time is set and the cor rect time zone is shown GRIB
148. rnational cooperation in meteorology and hydrology In 1961 the WMO developed the concept of the World Weather Watch WWW whose goal is to keep the entire atmosphere under continuous surveillance The nuts and bolts of the WWW are laid out in its Global Observation System GOS and data is used reprocessed and shared according to the WWW Global Data Processing System GDPS However the technical breakthrough that makes this all possible is the Global Telecommunications System GTS This is a permanent communications network that facilitates the flow of global weather information The GTS s main link is the Main Telecommunications Network MTN which links Melbourne Moscow and Washington Connected to the MTN is a series of regional networks known as Regional Meteorological Tele communications Networks RMTNs located at Algiers Beijing Bracknell Brasilia Buenos Aires Cairo Dakar Jeddah Maracay Venezuela Nairobi New Delhi Norrkoping Sweden Offenbach Prague Rome Sofia Tokyo Toulouse France and Wellington Within each country is its own National Meteorological Telecommunications Network NMTN There are also spe cialized networks connected to the GTS such as the U S Air Force s Global Weather Intercept Program which uses powerful receivers to collect and share weather data from politically and economically isolated regions The weather data is shared anong WMO member states who in turn set policy and proced
149. rt of this was to allow users to explicitly define the image type since Canada s ra dar imagery was a GIF file but was actually a PNG object 12 28 06 Support is added for NCEP high res front bulletins These are pro vided at http www hpc ncep noaa gov discussions codsus_hr and described at http www hpc ncep noaa gov html read_coded_bull_ hr shtml With these new bulletins frontal positions are located to the nearest tenth of a degree 6 nm resolution rather than nearest whole degree 60 nm There is no need to use the older format 12 29 06 Fixed Error 103 problem with GRIB import caused when certain data is not found ina file This was caused by incorrect file handling 12 29 06 Added support for public ECMWF data by making appropriate entries in digatmos grd Also introduced support for scaling of units based on digatmos grd entries Enabled support for Preferences gt Maps gt Label Graticule 12 29 06 Fixed incorrect symbol type used for thunderstorms in METAR reports Digital Atmosphere was mapping TSRA TSSN TSGR etc to the ww code 91 94 sections rather than 95 99 This has been fixed 12 29 06 Added thread processing command to code just before FTP uploads to allow system to catch up This was resulting in null FTP uploads 12 29 06 Enabled check for updates module to compare program version num ber with production version number on website and ask user once whether they want to update 12 29 06 A
150. rtcuts Shortcuts are performed by prefixing an asterisk in a point title when point mode is on These may then be invoked by placing the title in brackets Bracketed items will be replaced with the coordinates of the point where it was defined earlier This will plot a line from Baker to points in between and ending at Charlie 110 332217N 334910N START BAKER 332540N 332846N 333331N 333728N 334549N 334555N 334617N 334751N 334813N 334905N Appendix POINTS 960758W BAKER NOLABEL 960327W CHARLIE 960710W 960705W 960709W 960720W 960707W 960636W 960629W 960601W 960519W 960334W CHARLIE 111 APPENDIX Map attribute file structure OUUUUUUUUUUUU UUU ULU HUUU ULU UULU UULU ULI ULUL LUUL LU Nh ldhddddihdlldiidilililidllilii illiee FOR ADVANCED USERS This section contains advanced information for technically inclined users only iil Ud iddddlddddddiddddidd did IOU This file ending with the file extension ATR is associated with each map which is saved to disk The attribute file is structured as follows Number Purpose real Central latitude degrees real Central longitude degrees real zoom setting 3963 z where z map width in miles integer Not used integer Not used integer Not used integer Not used integer Map height pixels integer Map width pixels integer Offset x direction pixels integer Offset y direction pixels NOTES Real types have t
151. ry to choose the smallest da tasets as even the smallest ones will contain a vast amount of data The larger ones may crash Digital Atmosphere A good dataset usually ends in awp211 These are GRIB sets but will not have a grb extension To get them to show up you will need to change the filetype to AWIPS or all when choosing a GRIB file to import http nomad3 ncep noaa gov New as of 2006 http www globalmarinenet net grib htm http www ecmwf int products realtime d gts essential New NWS GRIB filename convention Since 2002 the NWS has used a hierarchichal naming convention that forms a URL An example is http weather noaa gov pub SL us008001 ST opnl MT eta_CY 00 RD 20031009 PT grid_DF gr1 fh 0000_tl press_gr awp211 This shows that at the central server location SL us008001 one can find operational status data ST opnl consisting of the Eta 00Z cycle model MT eta_CY 00 produced on 09 Oct 2003 RD 20031009 Within this one can find GRIB data PT grid_DF gr1 consisting of data for the 00h fore cast hour mapped onto the AWIPS 211 grid fh 0000_tl press_gr awp211 120 Appendix GRIB DATA For more information on this naming convention see http www nws noaa gov datamgmt filstnd html Directory and File Naming Standards and http www nws noaa gov datamgmt teftp_file_reference html TGFTP File Reference Information on grids is at http wwwt emc ncep noaa gov mmb etagrids Old NWS GRIB file
152. s Determines a radius of influence used in the Weighted Cressman and Barnes analysis method for upper air data This value should approximate the average spacing between upper air stations E Gamma Determines a gamma used in the Barnes analysis method for upper air data E Reduction Determines a reduction value used in the Cressman analysis method for upper air data Styles tab With Digital Atmosphere you are not stuck having to use one set of map colors line styles and fonts for everything Obviously when you want to use a different color set this means spending a lot of time mak ing tedious changes Digital Atmosphere allows you to manage sets of colors fonts and line settings These sets are known as styles A style is identified by a plaintext name and a filename all styles are stored in the styles directory under Digital Atmosphere without exception To change the color settings use the Preferences gt Styles panel Advanced users may edit the files directly this will not hurt anything if a plaintext editor such as Notepad or MS DOS Edit is used Editing the parameters Listed here are the various codes that appear in the edit window Above all be sure you pick Save when you are done or your changes will be discarded E Code This is a predefined code that marks the parameter type for internal use It cannot be modified E Parameter This is a predefined code that is used to provide a plain language explanati
153. s and use the appropriate translucency algorithm based on whether it is closer to white or black If you get unusual results change your background color or regenerate the map preferably towards the white or dark end of the spectrum Mosaicing When plotting radar imagery for multiple sites an important problem arises when Digital Atmosphere has to decide which radar s data to use for a particular location The rule is that Digital Atmosphere plots the pixel for the nearest radar site The exception is when raster images such as echo tops composite reflectivity etc are displayed in this case the pixel with the highest detected level is used this raster rule took effect with Equinox v1 05 1 16 07 and later versions Theory of operation Data is selected with the digatmos rad file Data is imported into queue nid then is plotted The digatmos nxc file is used to define how fields are plotted and digatmos nex defines the colors Since the station identifier is not con tained within the data blocks the NEXRAD station table digatmos nxa is consulted this table is built from digatmos stn whenever doing a Recompile Tables command For advanced users who are customizing access URLs a list of valid product codes for Internet retrieval can be found at http www nws noaa gov tg radfiles html To get historical NEXRAD data visit http has ncdc noaa gov plclimprod plsql HAS FileAppSelect datasetname 7000 Level II data is at http
154. s Ph1 0 Ph2 90 Scale 1 and Offset 0 Set the Green and Blue Scale to 0 and Offset to 0 which will always provide a value of 0 for these components PH1 PH2 MIN MAX OFFSET Illustration of basic concepts of Ph1 Ph2 Scale and Offset o 90 180 360 108 109 APPENDIX Points The following section shows how to construct files that produce points and lines The files should be created using a plaintext editor like Win dows Notepad Coordinate pairs Coordinate pairs are in the format LAT LONG Points may be defined in DDMMSSX DDMMSSxX format where X is N S E or W as appropriate Points may also be defined in decimal format DD DDDD DD DDDD The format is described below Points Points are plotted by writing them as such 350216N 964717W Joes Place NOLABEL 325455N 963746W Edgar 344705N 953806W IBM You may suffix a point with a symbol pipe and write NOLABEL NO BOX or both to prevent those attributes from appearing on the map Lines Lines start with START From there on all points will be connected with a line To turn line mode off and go back to points use WEND To start a new line write START again an END is not required You may write comments on the end these will not be plotted if line mode is on This example plots a line from five points START 322540N 960710W Leadout N 322846N 960705W 324751N 960601W 322221N 960748W 332652N 960055W Using sho
155. s is not acceptable but a slight disk space penalty is fine However some older browsers mainly from before 2000 do not recognize PNG graphics E BMP Windows bitmap This is recommended for accurate lossless renditions of the graphic where large filesizes are acceptable The wide spread use of BMP files are not recommended as there is no compression Chapter Four MAP MENU 35 and images may consume large amounts of disk space a 2000 x 1500 pixel image will use 10 MB as compared to 1 MB or less with JPEGs and GIFs Note that it creates 24 bit bitmap files that are not compatible with older graphics viewers especially those written before 2000 and nearly all written before 1996 Cursor city distance For United States locations this causes the status line at the bottom of the screen to display the coordinates from the nearest town or city to the cursor position This allows you to quickly judge the distance to a storm or other target from the closest town You may adjust the sensitivity to large vs small towns by changing the cursor city sensitivity factor in Digital Atmosphere s Preferences gt Misc tab This sensitivity may vary from state to state as we have not fine tuned the data and some experi mentation will be required The source of the city data is digatmos cty which is in text format and may be freely modified by users for applica tions in non U S countries Click this selection to enable it a checkmark will
156. s technique however it makes successive corrections using a smaller and smaller radius of influence to eliminate all errors It takes more time but the results are good In data sparse areas it is common for there to be erroneous contours especially if Digital Atmosphere is tasked to determine the best station spacing Strengths It s sophisticated and flexible and it may retain more mesoscale structure Weaknesses It can t resolve short wave length components it can require a large amount of time and it can fail with extreme data distribution Analysis settings These are used to control the performance of the selected analysis type Certain choices may be grayed out depending on the analysis type se lected and whether automatic smoothing is in effect E Smoothing coefficient Sets the mathematical value of s for the smoothing equation This affects what kind of wavelengths will be filtered in the analysis grid E Smoothing passes Determines how many times a smoothing opera tor will operate whenever it is called With this you can set how smoothed the maps will look when the analysis is complete This should be set to 1 or to a low non zero value E Surface radius Determines a radius of influence used in the Weight ed Cressman and Barnes analysis method for surface data This value should approximate the average spacing between surface sta tions Chapter Twelve PREFERENCES 89 E Upper radiu
157. s than 500 ft or visibility less than 1600 meters 142 Appendix ANALYSIS THEORY Objective analysis functions Nearly all of these algorithms use a smoothing coefficient s of the range 0 1 which is obtained directly from the Preferences gt Analysis panel This smoothing coefficient is used by the smoothing operators to remove unnecessary noise which would be otherwise evident in the data field The Barnes and Cressman algorithms also depend on the average sta tion spacing a This may be computed automatically by setting the Preferences gt Analysis gt Automatic Smoothing checkmark to checked A manual value may be specified by setting the above checkmark to unchecked and the algorithms will use the values specified in Surface Radius or Upper Radius Nearest Neighbor analysis The Nearest Neighbor method is a crude algorithm designed for brute speed Each observation is simply mapped to the nearest gridpoint overwriting any previous values that exist for that gridpoint Empty gridpoints are filled using an Expansion operator that nudges data from filled to void areas see Expand Then one pass of the HaltinerSmooth operator q v is performed to remove noise from the field using what ever smoothing coefficient has been chosen by the user in the Preferences gt Analysis panel Weighted analysis This is a single pass objective analysis that simply uses distance depen dent values of observations Then values at each observati
158. s who want the ability to script or to construct elaborate analysis commands See the Appendix under Scheduler Scripting and Analysis Scripting for full details Scheduler command Enter a single script command manually see the section in the Appendix for more information It will be executed immediately 12 STATUS CI show memory use Chapter Two DISPLAY COMPONENTS Scheduler Run Immediately executes a selected script file Scheduler Create Creates a new script file This is basically a plain text editor that loads and saves the file with a script extension Scheduler is off on Turns the scheduler on and off Turn it on for the scheduler to take effect It will trigger the execution of script files at the times you select Scheduler display window Shows the current schedule that will be executed if you turn the scheduler on The first four digits are the UTC time at which the script will be executed Following this is the script file that will be executed at that time UTC time readout Displays the current UTC time so you can see whether a script might execute soon Analysis command Advanced users may type in an analysis com mand here or paste it from a text editor When you press the lt EN TER gt key the command will be executed See the Appendix for help on building an analysis command script l Status box This panel shows all status messages displayed by Digital Atmosphere while it is in
159. second part is the pointer search string as shown here pointerurl pointersearch If Digital Atmosphere encounters this it will go to the URL indicated by pointerurl then will search that page for any text fragment containing pointersearch obtain the location where this occurs within quotation marks and add this to the pointer URL to construct a new URL For example this URL http www spc noaa gov products outlook day1lotlk html products outlook archive is used by Digital Atmosphere to obtain convective outlooks Obtaining the first page we open it and find this HTML fragment CLICK TO GET lt a href products outlook archive 2006 KWNSPTSDY1_ 200612301300 txt gt WUUSO1 PTSDY1 lt a gt PROD Digital Atmosphere extracts the products outlook archive 2006 KWNSPTSDY1_200612301300 txt part and appends it to the pointer URL to get the final URL of 46 Chapter Five DATA MENU http www spc noaa gov products outlook archive 2006 KWNSPTSDY1_200612301300 txt Solving access problems Digital Atmosphere must have access to a true Internet connection in order to retrieve data If for some reason you can t retrieve data through Digital Atmosphere all is not lost You can still use your Internet browser to get products then save them to your Digital Atmosphere data directory which is most users have had to do up until 1997 Technical tip Do you want to swap data product lists with other users No probl
160. setting in File gt Preferences gt Map Date stamp Overlays the date stamp at the top of the map 41 Annotations This allows temporary annotations to be set which override the annota tions set in Preferences gt Annotations Change credits Sets text to be plotted in the lower left as a credit This will temporarily override the credits set in File gt Preferences gt Annotations until the value is deleted or the program is restarted Change title Sets text to be plotted as a title This will temporarily override the title set in File gt Preferences gt Annotations until the value is deleted or the program is restarted 42 43 CHAPTER 5 Data menu The data commands display non analyzed meteorological fields The avail able options are shown briefly below Retrieve data This module retrieves weather data through the Internet and automati cally imports it for you This means you can immediately begin plotting and analyzing To use Retrieve Data you must already have a connection to the Inter net through your service provider before this command will work If you are using a firewall program be sure to grant Digital Atmosphere permission to use the Internet Most users do not use proxy servers but if you do enter the information in File gt Preferences gt Miscellaneous When you select Retrieve data you will be presented with a dialog box containing a list where you can check off the items you want to
161. sis operations are performed with on screen results in mind Since the pixel size of a window rarely exceeds 1200 x 1200 pixels this allows for 40 x 40 pixels within each grid box This is close to the minimum level of meaningful on screen data for most users Therefore it has not been anticipated that it is necessary to boost the analysis domain be yond 30 x 30 gridpoints and we have received few such requests Each objective analysis is an operation that starts completely from scratch each time therefore there are no complicating factors involved in moving the screen window to a different part of the world The floating domain simply moves to whatever geographic area is displayed and is not used until an analysis is requested Entry When a field is chosen for analysis or contouring Digital Atmosphere enters the contouring module through the GenerateContour function Here it is first determined whether a scalar or vector field must be calcu lated Ifitis a scalar field program flow goes directly to ObjectiveAnalysis If itis a vector field ObjectiveAnalysis is called for each component of the analysis i e for wind calculations a calculation is done on the U and then the V wind component Following this objective analysis a contouring or grid plotting routine is called to display the data The workings of this routine will not be discussed in this paper 140 Appendix ANALYSIS THEORY Processing functions ObjectiveAnal
162. sm or m are in metric or English according to File gt Preferences gt Station Plots gt Station Plot Units unless otherwise specified here Blank TEMP TEMP 10 DWPT DWPT 10 GUST RH MXR THETA THETAE WINDCHILL HEATINDEX SLP ALSTG WX VIS ELEV CIG OKTAS ID ICAO ID WMO PCPO1 PCPO6 PCP12 PCP18 PCP24 PTEND CLD L CLD M CLD H CLDHGT CLDAMT SHIPDIR SHIPSPD SEATEMP TEMPTYPE WAVEPD WAVEHGT SEAINSTHGT WINDPD Nothing will be plotted in this space Air temperature in whole degrees C or F Air temperature in tenths C or F Dewpoint in whole degrees C or F Dewpoint in tenths C or F Wind gust kt Relative humidity Mixing ratio g kg Potential temperature deg K Equivalent potential temperature theta e Wind chill Heat index Sea level pressure mb Altimeter setting in Hg Pictogram of current weather type Prevailing visibility sm or m Elevation ft or m Ceiling hundreds of feet Cloud cover in oktas eighths Station identifier 4 letter ICAO Station identifier 5 digit WMO Precipitation during past 1 hour Precipitation during past 6 hours Precipitation during past 12 hours Precipitation during past 18 hours Precipitation during past 24 hours Pictogram of pressure tendency during past 3 hours Pictogram of low cloud type Pictogram of middle cloud type Pictogram of high cloud type Cloud height code synoptic only SEE BELOW Cloud amount code synoptic only SEE
163. so modify the predefined analysis commands available in the Analysis Menu by using Analysis gt Edit analysis scripts or by directly editing digatmos mnu For more information see the appendix under Analysis scripting Edit analysis scripts This opens up an editor that shows the script command assigned to each analysis option in the Analysis dropdown menu This simply edits the digatmos mnu file For information on how to devise an analysis script command see Ap pendix gt Analysis Scripting How analysis works To fully understand how the analysis routines work you have to know a little bit about the theory behind them All meteorological fields can be described as a series of waves For example assume that at a certain time the coldest spot in the country is International Falls MN at 12 F and the hottest spot is Death Valley CA at 96 F Draw a long line on your map that passes through both of those points If you graph the temperatures along this line and gather data from cities along the line your tempera ture graph will show unique undulations rises and falls These are mathematical waves in the temperature field Assume that you find that the temperature 200 miles on each side of Death Valley along the line is 94 deg F You could then assume most of the southwest United States is hot The temperature graph would show 60 Chapter Six ANALYSIS MENU a gradual rise towards Death Valley and a gradual fall as you m
164. stern hemisphere which is Image width 800 pixels 4 E E negative Image height 600 pixels 4 5 Set Scale to 2000 miles The map Color style Regular analysis style z width hence will be 2000 miles apvancep PROPERTIES Expert users only 6 Set Image Width to 800 pixels xb Po _ Reaton 7 Set Image Height to 600 pixels geef o p deg 8 Leave Color Style on Regular QUICK PICK analysis style Likewise make By staten no changes to Advanced Proper By ication preset none z ties Zoom level None selected z 9 Click OK and wait about 10 to 60 Map size None selected z seconds while the map draws f K X Cancel Help You ll know it s done when you Pesce Tie Map configuration panel for this tutorial 2 Chapter One TUTORIAL see GENERATE Map completed in the Status Window at the lower left of the screen Loading some weather data Now that we have a map area defined we need some weather data to look at Do the following 1 Go to Data gt Retrieve data You will see an Internet retrieval panel pop up 2 Make sure only the following item is checked METAR from COD US only 3 At the top right of the panel it should show 1 resource selected If it shows more than that see if there are boxes you forgot to uncheck 4 If you don t know the current UTC time skip this step If you do check the Y M D H N to see if it shows the correct year month day hou
165. sure and outputs it to a file Note that this will probably not work on your computer without changes and is only in tended to demonstrate the appearance of script commands download http www atmos albany edu weather data1 surface syn Y M D S_syn wmo c digatm data test dat import c digatm data product plf 0 Test plot product slp 0 Test plot export d da20 bin map out jpg This script plots a series of upper air charts for 1200 UTC August 27 1990 from our Upper Archives CD ROM and saves the completed charts for 250 mb 500 mb 700 mb and 850 mb to individual files 1990082712250 gif etc Again this may not work on your computer without some changes set 1 9008 set 2 90082712 archive f 1 2 product plf 250 PLOT export d da20 bin shannon 19 2250 gif erase product plf 500 PLOT export d da20 bin shannon 19 2500 gif erase product plf 700 PLOT export d da20 bin shannon 19 2700 gif erase product plf 850 PLOT export d da20 bin shannon 19 2850 gif 131 APPENDIX Analysis scripting Analysis scripting is slightly different from scheduler scripting While sched uler scripts are designed to accomplish tasks in Digital Atmosphere such as accessing data displaying fronts and so forth the analysis script language is based solidly on logic and mathematics and is meant to build display products in a very flexible manner Note that you can run any analysis script command in a schedul
166. t from true ceilings where C E or M is prefixed 00to50m 50 to 100 m 100 to 200 m 200 to 300 m 300 to 600 m 600 to 1000 m 1000 to 1500 m 1500 to 2000 m 2000 to 2500 m 2500 m or more or no clouds Height of base of cloud not known or base of clouds at a level lower and tops at a level higher than that of the station OMANDTFEWNFH 106 107 APPENDIX Color gradient fills First the value 0 for minimum possible and 1 for maximum possible is fitted to the sine wave to determine what the amplitude will be Amplitude will always be in the range 1 to 1 Amplitude is determined by ph1 and ph2 which are in degrees A greater difference between ph1 and ph2 will result in a more curved function while a smaller difference will produce a flatter function For basic users the sine responses are as follows sin 0 0 sin 90 90 sin 180 0 sin 270 1 Amplitude sin ph2 ph1 Value phi Finally the amplitude is modified according to the user defined scale and offset values to determine ColorValue which must always be in the range 0 1 0 is dark 1 is bright This means if an Amplitude value is negative it must be offset so that it falls into the range 0 1 An out of bounds ColorValue is always rounded up or down so that it equals 0 or 1 ColorValue Amplitude Scale Offset Example For a basic scale where cold temperatures are black and hot temperatures are bright red set Red
167. ta If un checked no wind barb is plotted on any report Fill dewpoint depres sion circle If checked Digital Atmosphere will shade in the station plot of each upper level station whenever the dewpoint depression is determined to be 5 deg C or less If unchecked all station plots are left unfilled E Fill dewpoint depression circle If checked the station plot circle will be filled if the dewpoint depression is 5 deg C or less This usually signifies cloud cover Plot model configurations For both surface and upper air plots a grid of dropdown boxes are set up in a way that represents the various data positions around a given station plot You can use these dropdown boxes to adjust the kinds of data that are plotted in the different positions Listed below are the dif ferent types of data that are valid Analysis tab General preferences E Small fonts This option simply controls what size and type of fonts are used to label contour lines on analysis charts The same thing ex cept with small fonts unchecked and negative fonts unchecked E Negative fonts Contour labels are plotted as white on black rather than black on white E Transparent fonts Controls whether the map below bleeds through contour labels Analysis type Specifies which mathematical algorithm is to be used to analyze the data field E Nearest neighbor This is by far the quickest and most users will use this setting Values ar
168. takes up a lot of system resources Memory consumption increases exponentially with an increase in both height and width Color style Selects a color scheme with which you want this chart to be permanently associated The color settings in this file will apply to this chart and any subsequent fields drawn to it Once this is selected you cannot change it without generating a new workchart Color styles may be edited in the File gt Preferences gt Styles panel or by direct editing files in the Digital Atmosphere styles directory Advanced properties You may use the advanced properties settings to distort the appearance of the map drawn orthographic only This can be extremely helpful for aligning a workchart with a satellite photograph Offset The offset is in pixels and controls how far the map is shifted up down or left right from the center map point that you create the default is 0 Aspect Independently controls the scaling factor for the map in both the X and Y dimension the default is 1 which is useful if a wider or narrower map is desired Rotation Allows the map to be rotated by a given value in degrees decimal degrees may be used positive is clockwise Quick pick Use the quick pick panel to quickly select a map location based on a known station Enter the station s identifier ICAO or WMO in the station box or choose a location preset The zoom level and map size controls will move the scale and ima
169. time which storm cells have the greatest significance Generally values above 40 kg m 2 are associated with severe weather The maximum possible displayable Chapter Seven RADAR MENU 69 value is 80 kg m 2 The product has a coverage radius of 124 nm witha resolution of 2 2 nm Severe weather probability SWP Displays the probability of severe weather based solely on the VIL algorithm This product is of extremely limited use for severe weather forecasting and must be used with caution Values are expressed as a percentage from 0 to 100 The product has a coverage radius of 124 nm with a resolution of 2 2 nm Mesocyclone Shear couplets are resolved vertically and with time to determine the ex istence of a storm mesocyclone If one is present it is displayed as a red circle The radius of the circle equals the reported radius of the mesocy clone Mesocyclones are resolved only within 124 nm of the radar Hail index The radar system contains a severe hail index SHI algorithm that relates the 45 dBZ level to the 20C height When the computed probability for hail for each storm cell exceeds a predetermined criteria it will be dis played as a green isosceles triangle If the triangle is small there is a 30 probability of hail 50 if it is filled If it is large there is a 30 prob ability of severe hail 50 if it is filled The maximum expected hail size MESH is displayed in the middle of the symbol rounded to the nearest
170. tive level is as is shown on the Time Toolbar If the active level is a non surface level Quality Control will only display upper air data If the active level is a surface level Quality Control will display only surface data The options you have are Accept Entry Saves the report as shown including any modifica tions you might have made Once you hit Accept Entry all changes become permanent Ignore Changes Ignores any changes that you ve made to the report and move to the next one Delete Report If the individual report is so corrupted that you know you won t want to use it you ll probably want to delete it This is the button to use Stop Search Stops sifting through the file saving any values that you ve already entered Note that QC displays all data within the bounding box even if it s fil tered out on the map so you may need to press Accept entry numer ous times until you find the station you want One way of avoiding this problem is to make the initial QC box as small as possible so that you get only the station you want Likewise it s possible that multiple reports for one station might be in the data you can change the bad data for each one or just delete the duplicate reports Since QC changes the formatted binary data files you will lose your changes if you re import the original data View raw data Sometimes you will want to go back and look at the original data Not only is
171. tripes 6 Vertical stripes VECTOR OUTPUT COMMANDS BARB Wind barbs BKNT Wind barbs BMPH Wind barbs BKMH Wind barbs VECT Vector grid STRM Streamline m s m s shown as kt m s shown as mph m s shown as km h oy das omnes Appendix ANALYSIS SCRIPTING 137 Shown below is the default content that ships with Digital Atmosphere Note that some lines may wrap onto the next line in this Help Viewer this should not be done in the actual file Default contents of digatmos mnu Default analysis menu DIGITAL ATMOSPHERE MENU COMMANDS The Standard Version is limited to a maximum of 100 menu commands The Professional Version does not have any limits Do not create more than 20 main categories SPECIAL TITLE SUFFIXES 1 Marks the sea level pressure analysis for toolbar shortcut SLP 2 Marks the temperature C analysis for toolbar shortcut DEG C 3 Marks the temperature F analysis for toolbar shortcut DEG F Temperature Temperature deg C 2 CONT CINT 2 COLOR 200 0 0 DASH TEMP Temperature deg F 3 CONT CINT 5 COLOR 200 0 0 DASH DEGF TEMP Potential temperature deg K CONT CINT 1 COLOR 200 100 0 DOTS THTA Wind chill deg F CONT CINT 5 COLOR 0 0 200 DOTS WCHL Wind chill deg C CONT CINT 5 COLOR 0 0 200 DOTS DEGC WCHL Max temperature 6 h deg F 3 CONT CINT 2 COLOR 200 0 0 DASH DEGF TX06 Min temperature 6 h deg F 3 CONT CINT 2 COLOR 200 0 0 DASH DEGF TNO6 Max temperature 24 h deg F
172. unnoticable or may corrupt an analysis Fortunately Digital Atmosphere provides a tool to help fix the problem To perform quality control simply drag the mouse over the location where erroneous data is suspected A box will appear as shown below When you select File gt Quality Control or press the QC Speed Button the quality control panel will appear as seen below aio x Temperature deg C ICAO kso Dewpoint deg C wo Of Wind direction deg true Bir Wind speed kts Sa gier Wind gust Its LON 95 22 Sky cover oktas ELEY zos Ceiling feet00 TIME oss Ceiling method code MB LEVEL ps Weather WW code fs Visibilty word Deprecated text PUES al Visibility value meters Altimeter setting inx 100 Sea Lvl Pressure mb Ignore changes Pressure tendency mb x 10 no negs Pressure trend a code 0 to 8 __X Delete report_ Cloud codes L M H F s999 2399 fsss9 A EITE Maximumsminimum temperature tens of deg C Help Max 24 9999 Max 6 9999 Min 24 fssas Ming 9999 Precipitation mm x 10 1 hr fi 6 hr j 15hr 1 2hr fa Shr j 18 hr 1 3hr fa 12 hr fa 24 hr 1 You may then edit the values shown and correct any entries that look suspicious Always use a value of 9999 to indicate missing data Press Stop Search at any time when you are done changing data and your changes will be saved Chapter Three FILE MENU 23 Note that the data shown in the QC Panel is dependent on what the ac
173. ures for sharing data with the private sector In the United States the data is distributed to the public through the National Weather Service s NOAAPORT and FOS data feeds Much of this data reaches the Internet and is available free of charge This puts affordable forecasting in the hands of millions of American citizens and business owners boosting economic productivity and earnings on a national scale Unfortunately in Europe Asia South America and even Canada long standing ultra conser vative government policies make the data available only to pilots mariners and big spenders i e large corporations The Internet is the ultimate GTS though and its presence has done much to break down these economic bar 156 Appendix ABOUT WEATHER DATA riers Surface weather data is transmitted in one of two main formats METAR and SYNOP The METAR format is used primarily at airports and has an hourly observation cycle It gives us the best picture of weather conditions in North America Europe and the Pacific Rim The METAR format is fairly readable and uses station identifiers prescribed by the International Civil Aeronautical Organization ICAO The SYNOP format is more detailed and uses exten sive numerical coding using numerical station identifiers prescribed by the WMO and typically has a 6 hour cycle It gives us the best picture of weather in South America Africa Asia Australia and Antarctica where meteoro logical observato
174. ving or using GRIB data Itis provided as is Comments are welcomed but we may not be able to respond to questions If you need help please access our public discussion group on our website at www weathergraphics com forum LLL LLL LL dedddddddddddddddddddddddddddddddddedddddddddddddddddddedeeeddddddddd as N LILI NOTICE GRIB2 data is not yet supported by Digital Atmosphere Widdddtdiddtddidididie x Suu Lh ish bb ssbb bdssisddsidddcdddddrdddddrddrddddddrddddddddddddddsdadddddaddaddddddddasdddddddadddadd Clear data directory This is a utility command that clears out the data subdirectory lt Digi talAtmosphere gt data Normally it does not need to be used unless suspi cious plots or contours occur and the user wishes to flush out all data This ensures that File gt Import does not inadvertantly retrieve files that do not belong It can also prepare the data directory in case the user wishes to place numerous files into the directory to be imported Once the directory has been cleared data that has already been imported and stored in native binary format will remain unaffected but Import directory will not work at all until new data is placed in the data direc tory via a file copy or via the Data gt Retrieve command Font mode This forces Digital Atmosphere to use one of two font modes when creat ing station plots and contour labels Truetype This includes all regular fonts on the user s
175. w bom gov au nmoc Obs IDY03100 doc Note that there may be restrictions on the use of Australian data so look into this before creating commercial products 150 151 APPENDIX Exported analysis grids Whenever an Analysis is performed on any data scalar isoplethed fields only Digital Atmosphere always exports its output to GRID TXT The output can then be imported into spreadsheets or analyzed further by other methods The output consists of 900 points 30 by 30 representing the value at each point of X and Y in the geographic area shown in the workchart window The X axis is left right in the window pointing right while the Y axis is up down in the window pointing down This means that the highest values of X and Y are found east and south respectively The latitude longitude of each X and Y point in decimal format is shown followed by the analyzed value at that point Here is a sample of output from GRID TXT LATITUDE LONGITUDE VALUE 42 435 107 721 1012 79998779 42 471 107 141 1012 84558105 42 505 106 560 1012 92547607 42 537 105 979 1013 08880615 OOOO x wOoOn 0 lt 152 153 APPENDIX Language support Support for output of the chart legends in another language can be obtained by editing the language txt file in the Digital Atmosphere directory Simply create a new section header at the end of the file like DANSK Then set the language by editing the Language line at the top Language DANSK T
176. whole inch if less than one inch an asterisk shows The hail index has a radius of coverage of 124 nm from the radar Tornado TVS This product uses the Tornado Detection Algorithm TDA to resolve velocity signatures that suggest a tornado The tornado signature is shown as a red filled inverted isosceles triangle An ETVS may also be displayed but the NIDS code does not provide for differenting TVS from ETVS signatures therefore they will appear the same The radius of coverage is 124 nm but is rarely detected outside of 60 nm since the algo rithm is unable to sample the lower portions of the storm at long ranges 1 hour precipitation OHP Radar reflectivity is summed with time to estimate the rainfall accumu lation in the coverage area This product provides an estimate of how much rain fell during the past hour The highest reportable total is 8 inches The radius of coverage is 124 nm with a resolution of 1 1 nm 3 hour precipitation THP Radar reflectivity is summed with time to estimate the rainfall accumu lation in the coverage area This product provides an estimate of how 70 much rain fell during the past three hours The highest reportable total is 8 inches The radius of coverage is 124 nm with a resolution of 1 1 nm Storm total precipitation STP Radar reflectivity is summed with time to estimate the rainfall accumu lation in the coverage area This product provides an estimate of how much rain fell during the
177. xpansion operator is used by certain objective analysis functions to systematically fill null gridpoint values by causing any null gridpoint to assume the value of a neighboring gridpoint which has valid data This assignment is done only if f is null and the source gridpoint i is not sae The calculation which is done in four directions to avoid smearing the field in a particular direction is done as follows For x 0 30 do for y 0 29 do fl feya For y 0 30 do for x 0 29 do f Fal For x 0 30 do for y 30 1 do f f y1 l For y 0 30 do for x 30 Ido f f l Xy xX L y Repeat until there are no instances of f null AverageStationSpacing This is used to determine appropriate filtering values In this function Digital Atmosphere measures the great circle distance between all points in the domain and all other points in the domain The result is the aver age of these values Therefore if there are n number of observations there will be 1 1 number of distance measurements which will be aver aged n 1 since the distance from an originating station to itself cannot be included References Barnes S L 1964 A Technique for Maximizing Details in Numerical Weather Map Analysis Journal of Applied Meteorology 3 396 409 Cressman G P 1959 An Operational Objective Analysis System Monthly Weather Review 87 367 374 Haltiner G J 1971 Numerical Weather Prediction John Wiley amp
178. ysis Upon entry of this function BuildWeatherDataFile and Build2DGrid are called in succession and if height calculations are involved and the user prefers Geostrophic Heights in Preferences gt Analysis the Calcu lateHeights function is called The module aborts if there are 5 or less observations in the domain i e not enough data Otherwise the Preferences gt Analysis panel is checked to see which ob jective analysis scheme is desired For Nearest Neighbor method Expand is called followed by one HaltinerSmooth iteration resulting in a crude but efficient objective analysis For Weighted method Weighted is called For Barnes method Barnes is called For Cressman method Cressman is called Following the objective analysis regardless of type Expand is called to make sure there are no null gridpoints This is necessary because some gridpoint locations may reside at a distance from the nearest observation that far exceeds a which itself is often used to establish the maximum radius of weighting At this point regardless of the analysis scheme the Smoothing Passes value is obtained from the Preferences gt Analysis panel and the cor responding number of HaltinerSmooth iterations are performed The primary purposes this serves is to smooth out remote gridpoints filled by the final Expand function pass BuildWeatherDataFile This function constructs a Domain Data File filename OUTPUT UX0 This is di

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