Synthesizer User Manual
Contents
1. 0 0 000 1200 0 0 3883 769775 3 D 3 75 0 16379 1 0 198 5 E po1008 0001 005 2010 08 19 18 28 20 355 0 0 051 1200 0 0 3883 769775 0 A 3 75 0 16379 1 0 193 2 432e 001 6 T po1008 0001 006 2010 08 19 18 28 20 355 0 0 000 1200 0 0 3883 769775 0 D 3 75 0 16379 1 0 194 11 L po1008 0002 011 2010 08 19 18 29 23 1064 0 0 033 1200 0 0 3883 770508 0 A 3 75 0 16379 1 0 203 292 12 _ po1008 0002 012 2010 08 19 18 29 23 532 0 0 066 1200 0 0 3883 770508 3 A 3 75 0 16379 1 0 197 13 po1008 0002 013 2010 08 19 18 29 23 532 0 0 000 1200 0 0 3883 770508 3 D 3 75 0 16379 1 0 198 a tnnasnnns nsr anen nn anl annann ERP PPN ae a a ll ee aia mm d Fig 1 Synthesizer tool displays contents of a lidar database file and a joined signal under construction Toolbar buttons Functions of the toolbar buttons located at the top of the application window are as follows e Load DB Select a lidar database file to be loaded e Parameters Invoke a dialog that allows editing of parameters of the data grid to be applied to synthesized lidar signals see Synthesized Signal Data Grid section This same data grid will also be applied to any of the lidar signal plots displayed in the lower part of the application window e Chop Left and Chop Right green colored buttons Cut off the respective section of the currently selected lidar signal as determined by the height marker in the plot area of the application window Note this2. By right clicking an appropriate section of the signal plot one may query some additional information about the displayed signals at a given height above the measurement point This additional information is displayed on the left side of the window and has the following meaning e distance Distance to the selected signal strobe as defined by the height marker from the measurement point along the sounding track in meters e height Height of the selected signal strobe above the measurement point in meters e raw value Raw value of the currently selected green colored lidar signal at the selected strobe e raw accumulated Raw value of the currently selected lidar signal at the selected strobe multiplied by its accumulation Note this field will only be visible if the currently selected lidar signal was measured in digital i e photon counting mode e join raw value Raw value of the joined or averaged signal being currently constructed yellow colored at the selected strobe e join accumulated Raw value of the joined or averaged signal under construction at the selected strobe multiplied by its accumulation Note this field will only be visible if currently selected synthesized signal strobe had originated from a lidar signal measured in digital i e photon counting mode e join zenith zenith angle for the input signal that the currently selected synthesized signal strobe had origin
3. any Green color is used to denote lidar signals loaded from the database whereas yellow color denotes joined or averaged lidar signals under construction Units displayed along the horizontal axis of the plot area are indices of the lidar data grid as defined by Parameters dialog box see Synthesized Signal Data Grid section An important element within the signal plot area is height marker whose position is changed whenever the user clicks the plot area with right mouse button Mouse wheel may be used to alter position of the height marker as well Lidar data grid index defined by that marker is used by Chop Left Right and Join Left Right commands invoked from the toolbar In addition that same index is used to fill in lidar signal attributes displayed in the leftmost part of the application window The following topics will cover the mentioned application s interface elements in more detail T E NASB databases version Olti T182820_NC mdb 0I 0 F d 2 DB Parameters Left 2 Right Join o Join A Chop Left Chop Right New Average ies Joined Save Joined E Date Time Wavelength Bgd Accum Zenith Julian Polar Mode Step N1 N2 Aperture Board Reg E po1008 0001 000 2010 08 19 18 28 20 1064 0 0 033 1200 0 0 3883 769775 0 A 3 75 0 16379 1 0 203 height 3 E po1008 0001 001 2010 08 19 18 28 20 532 0 0 066 1200 0 0 3883 769775 3 A 3 75 0 16379 1 0 197 1590 00 2 f 2010 08 19 18 28 20 532
4. available values will be displayed in the dialog accompanied with round buttons that behave like check boxes The only exception is Date column filter dialog where required date values have to be manually typed in using YYYY MM DD notation In both types of filter dialogs one may use Select All button to check all the values present in the database thus effectively deactivating the filter in one click or Clear All button to remove all the values from the list the latter is useful when one needs to select only a single item out of a large number of values Enter a comma separated list of dates 2010 02 08 2010 02 23 Clear All Select All iv Fig 2 Wavelength and Date column filter dialogs Signal plot area and information bar In the lower part of the window a plot is displayed that may hold one or two lidar signals denoted with different colors Green colored lidar signal will always correspond to the currently selected row of the data table Thus it s always a signal read from the database However its grid parameters could differ from the original ones see Synthesized Signal Data Grid section whereas its boundaries could be altered by the user with Chop Left and Chop Right toolbar buttons On the other hand yellow color is used to represent a joined or averaged signal that is being currently constructed and thus has not yet been written to the database
5. Synthesizer Tool User Manual Introduction Synthesizer tool may be used to merge several lidar signals into a single effective signal Just like the TropoExport tool Synthesizer operates on lidar measurement database files in Microsoft Access format With this tool one may open an existing lidar database file combine existing lidar signals into synthesized ones and then append these newly created signals to the original database TropoExport tool may be used then to process both synthesized and ordinary raw lidar signals in the same manner Primary tasks of Synthesizer tool are signal joining and signal averaging Signal joining is useful when there are several lidar system setups available and each of these setups is designed to serve its own distinct sounding distance range Most often there would be two such lidar setups the first one intended for measuring of aerosols in the higher atmosphere and the second one intended for aerosols near the ground When two lidar signals are joined they are glued together in a juncture point Signal profiles above and below the juncture point are borrowed from the respective sections of the input signals In order to obtain a contiguous synthesized signal an appropriate multiplication factor is applied to one of the inputs during the procedure If there s a need to join three or more lidar signals several two signal join procedures may be carried out in a row to achieve the required effect The
6. are denoted with a check mark as determined by the Mark column of the lidar database table Note this command won t have any effect if there s an active signal joining or averaging procedure Exit Close the application Lidar database table When a lidar database has been loaded with Load DB toolbar button its contents are displayed in the table in the upper part of the window Each row of the lidar data table corresponds to a single lidar signal stored in the database file Values in the columns of the table have the following meaning Mark A check box used to mark measurements in the database During a signal averaging procedure this check box is used to select input measurements to be averaged see Lidar Signal Averaging section When no signal averaging or signal joining is being performed this check box is used to select measurements to be deleted from the database with Delete toolbar button Local Textual identifier of the lidar measurement Date and Time Starting date and time of the measurement Wavelength Lidar channel wavelength in nanometers Bgd Background signal Accum Accumulation of the lidar signal Zenith Zenith angle of the measurement in degrees Julian Starting Julian day of the measurement Polar Type of the measured lidar signal 0 for unpolarized signal 1 for Raman signal 2 for cross polar
7. ated from Synthesized Signal Data Grid Data grid parameters of synthesized lidar signals of any kind both joined and averaged that are created within the Synthesizer application are determined by the values entered by the user in Parameters dialog box invoked from the toolbar see Fig 3 The same data grid parameters will also be applied to any of the plots displayed in the plot area in the lower part of the application window The meaning of these parameters is as follows e N1 N2 The first and the last indices of the synthesized signal data grid measured from the measurement point along the nominal sounding track e Step Step of the synthesized signal data grid along the nominal sounding track in meters e Zenith Zenith angle of the synthesized signal s nominal sounding track in degrees The sounding track is called nominal here because this zenith angle is used to merely define the data grid of a synthesized signal and it has actually nothing in common with zenith angle of the original lidar measurement in fact original zenith angle of a joined signal may even vary with height In the dialog there are two convenience buttons that make it possible to select the most common sets of data grid parameters in one click Set default values buttons will reset all the parameters to values stored in parameters ini file located in the same folder where application s executable file re
8. command won t work in the averaging mode And in any case it won t actually make any changes to the database file If you want to create a chopped copy of an existing lidar signal use this command in combination with New Join and Save Joined e New Join Start a lidar signal joining procedure see Lidar Signal Joining section Join Left and Join Right Perform signal joining at the currently selected height as determined by the height marker displayed in the plot area of the application window see Lidar Signal Joining section Chop Left and Chop Right yellow colored buttons Cut off the respective section of the joined or averaged plot under construction as determined by the height marker displayed in the plot area of the application window this is similar to the analogous green colored buttons but applies the action to the yellow colored plot instead of the green colored one New Average Start a lidar signal averaging procedure see Lidar Signal Averaging section Clear Joined Cancel current signal joining or averaging procedure without saving any changes to the database file Save Joined Finish current signal joining or averaging procedure and save the constructed synthesized lidar signal in the database file The newly created database record will be inserted at the end of the database Delete Delete from the database file any lidar signals that
9. emoved from the Mark column and all the table column filters are completely reset thus all the table s rows become visible regardless of their visibility state prior to the average procedure Chop Left and Chop Right toolbar buttons may be used during an averaging procedure as well Signal boundaries defined by means of these buttons will then be applied to all the signals in that averaging session Unlike the signal joining procedure chopping does not lead to deletion of any intermediate data here so chopping is actually a reversible command in the averaging mode If an averaging procedure starts with a measurement in digital D receiver mode a special calibration t ns input field becomes active in the lower left corner of the application window This field makes it possible to adjust calibration time in nanoseconds for the digital receiver Lidar signal correction induced by the calibration time parameter is as follows i 0150 where P n is the lidar signal t is the calibration time and Az is height step of the lidar data grid The same correction is applied to the background signal Note this signal correction is intended for detectors of non paralyzable type only To complete an averaging procedure and save the data to the database the user has to press the Save Joined toolbar button Od 5 z S x
10. ignal projected onto a custom grid defined by the Parameters dialog box Lidar Signal Averaging To start a lidar signal averaging procedure the user has to press New Average toolbar button When a new averaging procedure is started any previous joined or averaged signal that has not been saved to the database would be discarded Averaged signal is defined to be the weighted average of the signals of all the lidar measurements that are currently visible in the lidar data table and have a check mark in the Mark column of the table Thus there are two ways of modifying an averaged signal under construction First one may use the check boxes to manually select or deselect required measurements Second it is possible to use table column filters to alter visibility of the table s rows Whenever a lidar signal averaging procedure is started all the measurements in the database are marked with check marks in the Mark table column At the same time all the lidar data table column filters are switched on and become active so that only table rows whose respective values coincide with those of the currently selected measurement remain visible If such a filter setup turns out to be too restrictive it has to be changed manually through column filter dialogs see Interface Elements section Similarly whenever an averaging procedure is completed through the Save Joined button or cancelled all the check marks are r
11. ized lidar signal an 3 for parallel polarized lidar signal Mode Measurement mode of the receiver A for analog mode and D for digital i e photon counting mode Step Step of the measurement data grid along the sounding track in meters N1 N2 The first and the last indices of the measurement data grid Aperture Aperture of the receiver in degrees Board Textual identifier of the receiver Reg Registration number of the receiver s channel VP1 Auxiliary field It will be Joined for joined lidar signals and Averaged for averaged ones Rows of the lidar data table may be filtered out so that only database records with specific values in certain table columns namely Date Wavelength Zenith Polar Aperture Board Reg and VP1 are displayed Table columns that have filters associated with them are denoted with headers of either blue or yellow color Blue color of a header indicates that the corresponding column filter is currently inactive i e it does not actually filter out any of the table s rows whereas yellow color of a header indicates active column filters i e those that force some of the table s rows to be hidden To activate reset or modify a column filter one has to click the column s header and then select the required values in the filter dialog box see Fig 2 Usually all the
12. procedure of signal averaging is useful when several consecutive lidar measurements are available for a common sounding distance interval By averaging these signals one may reduce measurement errors at the cost of increasing time interval of the resulting synthesized signal Signal joining and signal averaging procedures will be covered in more detail in Lidar Signal Joining and Lidar Signal Averaging sections respectively Besides signal joining and averaging Synthesizer tool may also be used to modify a lidar measurement s data grid i e to project the data onto a grid with custom data step and zenith angle and also to cut off unrepresentative or noisy lidar signal sections chop the lidar data Both these auxiliary tasks are to be carried out in the context of a join command and thus they will be covered in the Lidar Signal Joining section A general description of the application s user interface is given in the following Interface Elements section Interface Elements User interface of the Synthesizer tool is similar to that of TropoExport see Fig 1 The topmost part of the application window is occupied by a toolbar Below the toolbar a table is located that displays contents of the loaded lidar database file In the lower part of the application window there s a plot area that will display the currently selected lidar signal as well as the synthesized joined or averaged signal under construction if
13. reen colored signal are discarded to the right of the join marker i e above the join height 3 The remaining portion of the currently selected signal is multiplied by an appropriate factor in order to achieve combined signal s continuity in the juncture point 4 Two signals are glued together and become the current joined signal Immediately after a join command is completed correction factor input field becomes active in the lower left corner of the application window This field may be used to manually correct the matching factor applied to the newly added join plot segment Such a correction may be required if noise level of one or both of the input signals is high The final matching factor is defined to be the product of the automatic one and the correction factor The algorithm of a Join Right command is entirely symmetrical to that of the Join Left Chop Left and Chop Right commands are essentially Join Left and Join Right interrupted after the first step Both join and chop commands are irrevocable in the context of a single signal joining procedure To complete a joining procedure and save the data to the database one has to press the Save Joined toolbar button The final joined signal may consist of an arbitrary number of input signal segments If no join commands have been carried out during the procedure this resulting signal would effectively become a section of an input s
14. sides Load from database button will set all the parameters to those of the actual data grid of the currently selected lidar measurement this button will only work if a database file has been loaded If actual data grid of a lidar signal stored in the database differs from the required one i e that one which is defined by the Parameters dialog box then data stored in the database will be projected onto the new grid and linear interpolation will be used to obtain signal values at heights missing in the original grid Set default values 4 D Load from database Fig 3 Parameters dialog box Lidar Signal Joining A new joined signal is created when the user presses New Join toolbar button Note that this will clear any previous joined or averaged signal that has not been saved to the database The newly created joined signal will consist of a single segment whose boundaries will coincide with boundaries of the currently selected input signal Once a joined plot is created an arbitrary number of join and chop commands may be applied to it Prior to accomplishing any of these commands one has to select the join or chop height by right clicking the appropriate section of the signal plot The algorithm of a Join Left command would then be as follows 1 All the joined plot data to the left of the join marker i e below the join height are discarded Similarly all the data of the currently selected g
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