Product User Manual Fundamental Climate Data Record of SSM/I
Contents
1. channel Channel number Fixed dimension 7 channel_hifreq Channel number of high frequency channels Fixed dimension 2 compress channel Explanatory variables channel_name String representation of the corresponding channel number V19 H19 V22 V37 H37 V85 H85 scan_type_name String representation of the corresponding scan type A B Daily mean statistical variables rotation instrument rotational speed rpm dimension date hotc_var variance of hot load reading count 2 dimension date channel colc_var variance of cold load reading count 2 dimension date channel trhl_var variance of hot load temperature K 2 dimension date nedt noise equivalent temperature K dimension date channel Quality control variables qc_scan Scanline quality control bit mask dimension time All bits set to 0 indicates normal condition qc_channel Channel quality control bit mask dimension time channel All bits set to 0 indicates normal condition SAF CM DWD PUM FCDR_SSMI 0 1 17 04 2012 EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI CM SAF Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 qc_fov_lo Field of view quality control low resolution bit mask dimension time across_track_lores All bits set to 0 implies acceptable data qc_fov_hi Field of view qualit2. EUMETSAT Satellite Application Facility on Climate Monitoring The EUMETSAT Network of Satellite Application Facilities Climate Monitoring Product User Manual Fundamental Climate Data Record of SSM I Brightness Temperatures CM 150 FCDR_SSMI Reference Number SAF CM DWD PUM FCDR_SSMI Issue Revision Index 0 1 Date 17 04 2012 EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 Document Signature Table Author Karsten Fennig CM SAF scientist Editor Rainer Hollmann Science Coordinator MD 2012 04 17 Approval Rainer Hollmann Science Coordinator dl Release Martin Werscheck Project Manager WHERE Distribution List Internal Distribution ae Ne Copies DWD Archive 1 CM SAF Team 1 External Distribution PUBLIC Document Change Record Issue DCN No Changed Pages Paragraphs Revision 2012 04 17 SAF CM DWD PUM FCDR_SSMI Document under progress EUMETSAT SAF on CLIMATE MONITORING Doc No Product User Manual Issue FCDR SSM I Brightness Temperatures Date Table of Contents SAF CM DWD PUM FCDR_SSMI 0 1 17 04 2012 List of Figures 3 List of Tables 3 1 The EUMETSAT SAF on Climate Monitoring 4 2 Introduction 4 2 1 Applicable documents 5 2 2 Reference documents 5 3 The SSM l Instrument 5 4 Product definitions 6 5 Data format description 6 5 1 Data file contents 7 6 Data ordering
3. M SAF homepage www cmsaf eu The user service includes information and documentation about the CM SAF and the CM SAF products information on how to contact the user help desk and allows to search the product catalogue and to order products On the main webpage a detailed description how to use the web interface for product search and ordering is given We refer the user to this description since it is the central and most up to date documentation However some of the key features and services are briefly described in the following sections Copyright note All intellectual property rights of the CM SAF products belong to EUMETSAT The use of these products is granted to every interested user free of charge If you wish to use these products EUMETSAT s copyright credit must be shown by displaying the words copyright year EUMETSAT on each of the products used 6 1 Product ordering process You need to be registered and logged in to order products A login is provided upon registration all products are delivered free of charge After the selection of the product the desired way of data transfer can be chosen This is either via a temporary ftp account the default setting or by CD DVD or email Each order will be confirmed via email and the user will get another email once the data have been prepared If the ftp data transfer was selected this second email will provide the information on how to access the ftp server 6 2 Contact User H
4. ate Observing System The Global Land One kilometer Base Elevation The Hamburg Ocean Atmosphere Fluxes and Parameters from Satellite data Initial Operations Phase Koninklijk Nederlands Meteorologisch Institut Meteosat Second Generation National Aeronautics and Space Administration National Environmental Satellite Data and Information System National Oceanic amp Atmospheric Administration Product Requirement Document Product User Manual Quality Control Royal Meteorological Institute of Belgium Satellite Application Facility Swedish Meteorological and Hydrological Institute Special Sensor Microwave Imager Special Sensor Microwave Imager Sounder Antenna Temperature Brightness Temperature Temperature Data Records 14 Doc No SAF CM DWD PUM FCDR_SSMI 0 1 17 04 2012 EUMETSAT SAF on CLIMATE MONITORING Product User Manual FCDR SSM I Brightness Temperatures Doc No SAF CM DWD PUM FCDR_SSMI Issue 0 1 Date 17 04 2012 CMSAF 9 Appendix A Table 1 Global NetCDF attributes Name Description title dataset title summary short description of the data file content Conventions conventions followed CF 1 5 for all files Metadata_Convention netcdf_library_version institution creator_url creator_email references source cdm_data_type filename time_coverage_start time_coverage_end geospatial_lat_units geospatial_lat_min geospatial_lat_max geospatial_lon_units geospatial_lon_min geospatial_lo
5. ated by subtracting 60 rotation 1 9 s from the B scan time The FOV positions of the high and low resolution channels are co registered To get the FOV position of the lower resolution channel the across_track_lores coordinate variable can be used as an index to the A scan position arrays lat_lores lat time 0 across_track_lores This follows the CF convention for compression by gathering and the corresponding attribute compress is assigned to the coordinate variable across_track_lores Daily mean values have a fixed dimension date of size 1 5 1 Data file contents A common NetCDF file consists of dimensions variables and attributes These components can be used together to capture the meaning of data and relations among data Global attributes are summarized in Table 1 and possible variable attributes in Table 2 Appendix A The following variables thematically sorted are available in the FCDR data files Coordinate variables date Validity date days counted from 1987 01 01 00 00 00 UTC Fixed dimension 1 time B Scan start time seconds counted from 1987 01 01 00 00 00 UTC Record dimension across_track FOV across track position of high resolution channels Fixed dimension 128 across_track_lores FOV across track position of low resolution channels Fixed dimension 64 compress across_track EUMETSAT SAF on CLIMATE MONITORING Doc No Product User Manual Issue FCDR SSM I Brightness Temperatures Date
6. elp Desk staff In case of questions the contact information of the User Help Desk e mail address contact cmsaf dwd de telephone and fax number are available via the CM SAF main webpage www cmsaf eu or the main page of the Web User Interface 6 3 Feedback User Problem Report Users of CM SAF products and services are encouraged to provide feedback on the CM SAF product and services to the CM SAF team Users can either contact the User Help Desk see chapter 6 2 or use the User Problem Report page A link to the User Problem Report is available either from the CM SAF main page www cmsaf eu or the Web User Interface main page 6 4 Service Messages log of changes Service messages and a log of changes are also accessible from the CM SAF main webpage www cmsaf eu and provide useful information on product status versioning and known deficiencies 12 EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI 2 CM SAF Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 7 References Andersson Axel Bakan Stephan Fennig Karsten Grassl Hartmut Klepp Christian Phillip Schulz Joerg Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data HOAPS 3 monthly mean electronic publication World Data Center for Climate doi 10 1594 WDCC HOAPS3_ MONTHLY 2007a Andersson Axel Bakan Stephan Fennig Karsten Grassl Hartmut Klepp Christian Phillip Schul
7. he FCDR is available in the Validation report RD 3 EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 2 1 Applicable documents Memorandum of Understanding between AD 1 CM SAF and the Max Planck Institute for Meteorology and Meteorological Institute University of Hamburg 2 2 Reference documents CM SAF Product Requirements Document SAF CM DWD PRD 1 6 Algorithm Theoretical Basis Document Validation Report Fundamental Climate Data Record of SSM I SAF CM DWD VAL FCDR_SSMI 1 0 Brightness Temperatures RD 2 Fundamental Climate Data Record of SSM I SAF CM DWD ATBD FCDR_SSMI 1 0 Brightness Temperatures 3 The SSM I Instrument SSM I sensors have been carried aboard the DMSP satellite series since 1987 Up to three radiometers have been in orbit simultaneously An extensive description of the instrument and satellite characteristics has been published by Hollinger 1987 and Wentz 1991 Hence only a short summary of essential information is given here The DMSP satellites operate in a near circular sun synchronous orbit with an inclination of 98 8 at an approximate altitude of 860 km Each day 14 1 orbits with a period of about 102 minutes are performed The Earth s surface is sampled with a conical scan at a constant antenna boresight angle of 45 over an angular sector of 102 4 resulting in a 1400 km wide swath o
8. l resolution varies from 69 km by 43 km with a sampling frequency of 25 km for the 19 GHz channel to 15 km by 13 km with 12 5 km sampling frequency for the 85 GHz channel The EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI lt CM SAF Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 6 58 km sec Velocity Ground Track 102 Active Scan Angle 1 394 km Swath Width u Figure 1 SSM I scan geometry from Hollinger et al 1987 85 GHz channels are sampled for each rotation of the instrument A and B scans with a resolution of 128 uniformly spaced pixels while the remaining channels are sampled every other scan A scans with a resolution of 64 pixels see Figure 1 A fixed cold space reflector and a reference black body hot load are used for continuous onboard two point calibration 4 Product definition The CM SAF FCDR from SSM I brightness temperatures are compiled as daily collections of all observations from one sensor All sensor specific data available in the raw data records are provided as well as additional information like quality control flags Earths incidence angles averaged 85 GHz brightness temperatures incidence angle normalisation offsets and inter sensor calibration offsets 5 Data format description The CM SAF FCDR dataset is provided as NetCDF Network Common Data Format files http www unidata ucar edu
9. mension time nread trfr Forward radiator temperature K dimension time trrf R F mixer temperature K dimension time hotc Hot load reading count dimension time scan_type channel nload colc Cold load reading count dimension time scan_type channel nload rvolt Reference voltage dimension time nread age Automatic gain control setting dimension time scan_type channel md5 MDS message digest dimension time ndigest Sensor data variables tb Brightness temperature K dimension time channel across_track_lores ical Brightness temperature intercalibration offset K dimension time channel across_track_lores 10 EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI CM SAF Product User Manual Issue FCDR SSM I Brightness Temperatures Date eia_norm Brightness temperature earth incidence angle normalization offset K dimension time channel across_track_lores tb_hi Brightness temperature 85GHz K dimension time scan_type channel_hifreq across_track ical_hi Brightness temperature intercalibration offset 85GHz K dimension time scan_type channel_hifreq across_track 0 1 17 04 2012 EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI je CM SAF Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 6 Data ordering via the Web User Interface WUI User services are provided through the C
10. n CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI Product User Manual Issue 0 1 17 04 2012 FCDR SSM I Brightness Temperatures Date Table 2 Attributes assigned to variables Name Description long_name standard_name units C_format FORTRAN_ format valid_min valid_max scale_factor add_ offset _ FillValue flag_masks flag_meanings cbtf_parameter_id compress long descriptive name standard name that references a description of a variable s content in the CF standard name table physical unit udunits standards format string that should be used for C applications to print values for this variable applies to the scaled internal type and value format string that should be used for FORTRAN applications to print values for this variable applies to the scaled internal type and value smallest valid value of a variable largest valid value of a variable The data are to be multiplied by this factor after it is read This number is to be added to the data after it is read If scale_factor is present the data are first scaled before the offset is added This number represent missing or undefined data Missing values are to be filtered before scaling list of bit fields expressing Boolean or enumerated flags descriptive words for each flag value unique internal parameter ID Records dimensions which have been compressed by gathering 16
11. n the Earth surface Figure 1 A nearly complete coverage of the Earth by one SSM I instrument is achieved within two to three days Due to the orbit inclination and swath width the regions poleward of 87 5 are not covered To date six SSM I instruments have been successfully launched aboard the F08 F10 F11 F13 F14 and F15 spacecrafts All satellites have a local equator crossing time between 5 and 10 A M P M for the descending ascending node The F08 had a reversed orbit with the ascending node in the morning Also the Earth observing angular sector of the scan on this satellite is differently from the others centred to the aft of the sub satellite track Most of the DMSP satellites have a stable orbit The temporal variation of the equator crossing times is less than three hours for all satellites At the end of the time period the orbits of F14 and F15 begin to decay noticeably but are still within 2 3 hours of original time The SSM I is a seven channel total power radiometer measuring emitted microwave radiation at four frequency intervals centred at 19 35 22 235 37 0 and 85 5 GHz All frequencies are sampled at horizontal and vertical polarization except for the 22 235 GHz channel which measures only vertically polarized radiation The channels will be referred to as 19 22 37 and 85 GHz hereafter and the corresponding brightness temperatures of each channel and polarization as TB19v h TB22v TB37v h and TB85v h The spatia
12. n_max revolution_coverage_start revolution_coverage_end satellite _name satellite_id instrument_name scanlines_count scanlines_missing_count scanlines_coverage_percent dataset_version date_created date_modified history conventions followed Unidata Dataset Discovery v1 0 for all files NetCDF library version used institution where the data was produced URL contact information for the creator of the data email contact information for the creator of the data references that describe the data or methods used to produce it original data source data type swath for all files original filename temporal coverage start of the data ISO8601 date temporal coverage end of the data ISO8601 date latitude attributes unit latitude bounding box minimum latitude bounding box maximum longitude attributes unit longitude bounding box minimum longitude bounding box maximum revolution coverage start of the data revolution since launch evolution coverage end of the data revolution since launch spacecraft name e g DMSP F13 spacecraft number e g 13 instrument name SSM I total number of scan lines in the data file number of missing scan lines in the data file fraction of available scans in the data file FCDR version number date on which the data was created ISO8601 date date on which the data was modified ISO8601 date provides an audit trail for modifications to the original data EUMETSAT SAF o
13. software netcdf The data files are compiled following NetCDF EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 Climate and Forecast CF Metadata Convention version 1 5 http cf pcmdi Inl gov and NetCDF Attribute Convention for Dataset Discovery version 1 0 All SSM I FCDR products files are swath based and built following the same design principles The record dimension of the data files is the B scan integer time measured in seconds since 1 January 1987 Each file contains all possible scans for one complete day 22749 scans regardless of their quality and status Missing scans are marked as missing and sensor data are set to undefined in this case The users are advised to read and apply the supplied quality control flags gc_scan gc_channel qc_fov_lo and qc_fov_hi in order to filter incorrect and erroneous observations The quality control procedure and thresholds are described in the ATBD RD 2 To account for the higher 85GHz channels sampling see section 3 an additional dimension scan_type is used keeping the same record dimension as for the low resolution channels This keeps the file format compatible to the original NOAA NESDIS format and results in a 4 dimensional array for the 85GHz channel brightness temperatures time scan_type channel_hifreg across_track The observation time of the A scan can be calcul
14. to 2004 the Initial Operations Phase IOP and the Continued Development and Operations Phase CDOP The consortium of CM SAF currently comprises the Deutscher Wetterdienst DWD as host institute and the partners from the Royal Meteorological Institute of Belgium RMIB the Finnish Meteorological Institute FMD the Royal Meteorological Institute of the Netherlands KNMI the Swedish Meteorological and Hydrological Institute SMHI and the Meteorological Service of Switzerland MeteoSwiss After focusing on the development of retrieval schemes to derive a subset of Essential Climate Variables ECVs in the development phase CM SAF delivered to its users products based on Meteosat and polar orbiter data for Europe and Northern Africa supporting NMHSs in their provision of climate services in the IOP from 2004 to 2007 During CDOP lasting from 2007 to 2012 the product validation continued the time series were expanded and algorithms were further improved while the study domain was extended from the baseline area to the MSG disk for the geostationary products and to include global and Arctic coverage for the polar orbiter products In addition long term climate datasets from polar orbiting and geostationary satellites are being generated for climate monitoring i e HOAPS METEOSAT and AVHRR GAC based products A catalogue of available CMSAF products is available via the CMSAF webpage http www cmsaf eu Here detailed information about prod
15. uct ordering add on tools sample programs and documentation are provided 2 Introduction This CM SAF Product User Manual PUM provides information on the Fundamental Climate Data Record FCDR of Brightness Temperatures from the Special Sensor Microwave Imager SSM D The predecessors of this data record and the data processor suite have originally been developed at the Max Planck Institute for Meteorology MPI M and the University of Hamburg UHH for the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data HOAPS http www hoaps org climatology HOAPS is a compilation of climate data records for analysing the water cycle components over the global oceans derived from satellite observation Andersson et al 2011 The main satellite instrument employed to retrieve the geophysical parameters is the SSM I and much work has been invested to process and carefully homogenize all SSM I instruments onboard the Defence Meteorological Satellite Program DMSP platforms F08 F10 F11 F13 F14 and F15 Andersson et al 2010 A technical description of the data sets including information on the file format as well as on the data access is provided in this document Furthermore details on the implementation of the processing chain and individual processing steps are available in the Algorithm Theoretical Basis Document RD 2 Basic accuracy requirements are defined in the product requirements document AD 2 A detailed validation of t
16. via the Web User Interface WUI 12 6 1 Product ordering process 12 6 2 Contact User Help Desk staff 12 6 3 Feedback User Problem Report 12 6 4 Service Messages log of changes 12 7 References 13 8 Glossary 14 9 Appendix A 15 List of Figures Figure 1 SSM I scan geometry from Hollinger et al 1987 u 240rs44snsnsnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnannn 6 List of Tables Table 1 Global NetCDF attributes u40u0nnnnneennnnnnnennnnnnennnnnnennnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnnennensannennnnann 15 Table 2 Attributes assigned to Variables 244us4nnnnnnennnnnnnnnnnnnnnennnnnnnnnnnnnnnnnnnnnnnnnnnnnnennnnnnnennennnnennnnnnn 16 EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 1 The EUMETSAT SAF on Climate Monitoring The importance of climate monitoring with satellites was recognized in 1999 by EUMETSAT Member States when they amended the EUMETSAT Convention to aff rm that the EUMETSAT mandate is also to contribute to the operational monitoring of climate and the detection of global climatic changes Following this EUMETSAT established within its Satellite Application Facility SAF network a dedicated centre the SAF on Climate Monitoring CM SAF http www cmsaf eu Since the start of the CM SAF in 1999 the project went through three phases i e the Development Phase lasting from 1999
17. y control high resolution bit mask dimension time across_track All bits set to O implies acceptable data Geolocation variables tfrac B scan micro seconds 10 6 s dimension time To get the exact scan time add this to time lat FOV latitude degree_north dimension time scan_type across_track lon FOV longitude degree_east dimension time scan_type across_track laz FOV local azimuth angle degree_east dimension time across_track sft_lo FOV surface type for low resolution channels dimension time across_track_lores Possible types are water land coast sea_ice sea_ice_edge sft_hi FOV surface type for high resolution channels dimension time scan_type across_track Possible types are water land coast coast2 sea_ice sea_ice_edge rev Revolution number dimension time salt Altitude of spacecraft km dimension time slat Latitude of spacecraft sub satellite point degree_north dimension time slon Longitude of spacecraft sub satellite point degree_east dimension time EUMETSAT SAF on CLIMATE MONITORING Doc No SAF CM DWD PUM FCDR_SSMI Product User Manual Issue 0 1 FCDR SSM I Brightness Temperatures Date 17 04 2012 eia Earth incidence angle degree dimension time Calibration and sensor state variables slope Calibration slope K count dimension time channel offset Calibration offset K dimension time channel trhl Hot load temperature K di
18. z Joerg Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data HOAPS 3 5 days mean electronic publication World Data Center for Climate doi 10 1594 WDCC HOAPS3_PENTAD 2007b Andersson Axel Bakan Stephan Fennig Karsten Grassl Hartmut Klepp Christian Phillip Schulz Joerg Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data HOAPS 3 twice daily composite electronic publication World Data Center for Climate doi 10 1594 WDCC HOAPS3_ DAILY 2007c Andersson A Fennig K Klepp C Bakan S Gra l H and Schulz J The Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data HOAPS 3 Earth Syst Sci Data 2 215 234 doi 10 5194 essd 2 215 2010 2010 8 Glossary ATBD CM SAF DMSP DWD ECV EIA EPS EUMETSAT FCDR FMI FOV GCOS GLOBE HOAPS IOP KNMI MSG NASA NESDIS NOAA PRD PUM QC RMIB SAF SMHI SSM I SSMIS TA TB TDR EUMETSAT SAF on CLIMATE MONITORING Product User Manual Issue FCDR SSM I Brightness Temperatures Date Algorithm Theoretical Baseline Document Satellite Application Facility on Climate Monitoring Defense Meteorological Satellite Program Deutscher Wetterdienst German MetService Essential Climate Variable Earth Incidence Angle European Polar System European Organisation for the Exploitation of Meteorological Satellites Fundamental Climate Data Record Finnish Meteorological Institute Field of view Global Clim
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