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AWDP User Manual and Reference Guide v2.3

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1. Table 8 7 Fortran 90 BUFR modules 66 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Chapter 9 Module gribio_module Module gribio_module is part of the genscat support modules The current version is a Fortran 90 wrapper around the ECMWF GRIB API library see http www ecmwf int The goal of this support module is to provide a comprehensive interface to GRIB data for every Fortran 90 program using it In particular gribio_module provides all the GRIB functionality required for the scatterometer processor based on genscat Special attention has been paid to testing and error handling 9 1 Background The acronym GRIB stands for GRIdded Binary GRIB is maintained by the World Meteorological Organization WMO and other meteorological centres In brief the WMO FM 92 GRIB definition is a binary format for efficiently transmitting gridded meteorological data It is beyond the scope of this document to describe GRIB in detail Complete descriptions are distributed via the websites of WMO http www wmo int and of the European Centre for Medium range Weather Forecasts ECMWF http www ecmwf int Module gribio_module is in fact an interface On the one hand it contains temporary definitions to set the arguments of the ECMWF library functions On the other hand it provides self explaining routines to be incorporated in the wider Fortran 90 program S
2. 4 3 9 Module awdp Table 4 28 Routines of module awdp_icemodel Module awdp is the main program of AWDP It processes the command line options and controls the flow of the wind processing by calling the subroutines performing the subsequent processing steps If any process step returns with an error code the processing will be terminated 45 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Chapter 5 Inversion module 5 1 Background In the inversion step of the wind retrieval the radar backscatter observations in terms of the normalized radar cross sections o s are converted into a set of ambiguous wind vector solutions In fact a Geophysical Model Function GMF is used to map a wind vector specified in term of wind speed and wind direction to the o values The GMF further depends not only on wind speed and wind direction but also on the measurement geometry relative azimuth and incidence angle and beam parameters frequency polarisation A maximum likelihood estimator MLE is used to select a set of wind vector solutions that optimally match the observed o s The wind vector solutions correspond to local minima of the MLE function me EO OY y 5 1 Na K With N the number of independent o measurements available within the wind vector cell and Kp the covariance of the measurement error Following a Bayesian approach K is a constant represe
3. TDV_Exit Figure A 9 Calling tree for routine remove_ambiguities first level The full name of the 12 routine is 79 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 AllocRowsAndCellsAndInitBatch postprocess GetElapsedSystemTime monitoring speeddir_to_u speeddir_to_v get_lun free_lun get_lun free_lun get_lun free_lun Figure A 10 Calling tree for routine postprocess first level gt write_bufr_file GetElapsedSystemTime init_bufr_processing set_BUFR_file_attributes open_BUFF_file gt InitAndSetNrOfSubsets row_to_bufr_data Bufrint2Real set_beam_collocation set_kp_estim_qual set_wvc_quality save_BUFR_message gt close_BUFF_fille gt Figure A 11 Calling tree for routine write_bufr_file first level 80 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 gt init_cell init 12_wind gt Figure A 12 Calling tree for routine init _cell second level gt init 12_wind Figure A 13 Calling tree for routine init_12_wind second level gt test_cell test_beam Figure A 14 Calling tree for routine fest_cell second level gt print_cell print_time print_wvc_quality print_ambiguity print_process_flag Figure A 15 Calling tree for
4. properties Write the monitoring file without any processing Write some properties of the last row of the input file 18 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 The acquisition date and time and the sub centre id are written to a small ASCII output file properties txt writeonly Write all data to BUFR output without processing This mode is useful to copy an input file to BUFR output without processing Running the command awdp without any command line options will display a list of all available command line options with a short explanation on the console Running the command awdp with an illegal option will produce the same output but preceded by an error message The output will be written into a BUFR file with the name INSTR_YYYYMMDD_HHMMSS_SAT_ORBIT_srv_o_SMPL _CONT 12_bufr where e INSTR is the instrument ascat orscatt e YYYYMMDD_HHMMSS is the acquisition date and time UTC of the first data in the file e SAT is the satellite 6 characters ersl__ ers2__ metopa or metopb e ORBIT is the orbit number 5 digits of the first data in the file 00000 for ERS data e SMPL is the WVC sampling cell spacing 250 for 25 km and 125 for 12 5 km e CONT contents is omitted if the data contains both wind and soil moisture data Otherwise it is set to __ovw Ocean Vector Winds or __ssm Example ascat_20070426
5. 2 3 Reference Guide Date February 2014 Attribute Type Description ambig 0 144 ambiguity type Array of wind ambiguities ice icemodel_type Ice information stress_param nwp_stress param_type Wind stress information process_flag process_flag_type Processing flag level_of_ input integer Level of input data 1 or 2 Table 4 7 Cell data structure All soil moisture information is read from the input BUFR file into the cell data structure and not used within the program It is written to the output BUFR file at the end of the processing Full resolution data The fu _res_type contains average full resolution data read from a PFS file which are used to replace the 25 km or 12 5 km beam data The attributes are listed in table 4 8 The routine init full res sets the full resolution averaged data to zero The routine print_full_res may be used to print the full resolution data Attribute Type Description count_tot integer Number of full res measurements used lat real Mean value of full res lats lon real Mean value of full res lons count_fore integer Number of full res fore beams used incidence_fore real Mean value of full res values azimuth_fore real Mean value of full res values sigma0_fore real Mean value of full res values sigma0_sq_fore real Sum of squares land_frac_fore real Mean value of full res values count_mid integer Number of full res mid beams used incidence mid real Mean value of full res values azimuth_mid
6. size integer Size in bytes of BUFR message nr_of words integer Idem now size in words Table 8 2 Attributes for the BufrMessageType data type Attribute Type Description ksup 9 integer Supplementary info and items selected from the other sections ksec 3 integer Expanded section 0 indicator ksec1 40 integer Expanded section 1 identification ksec2 4096 integer Expanded section 2 optional ksec3 4 integer Expanded section 3 data description ksec4 2 integer Expanded section 4 data Table 8 3 Attributes for the BufrSectionsType data type Attribute Type Description Nsec0 integer ksup 9 dimension section 0 nsecOsize integer ksec0 1 size section 0 nBufrLength integer ksec0 2 length BUFR nBufrEditionNumber integer ksec0 3 Nsecl integer ksup 1 dimension section 1 nsecl size integer ksecl 1 size section 1 kEditionNumber integer ksec1 2 Kcenter integer ksec1 3 kUpdateNumber integer ksec1 4 kOptional integer ksec1 5 ktype integer ksecl 6 ksubtype integer ksecl 7 local use kLocalVersion integer ksecl 8 kyear integer ksec1 9 century year kmonth integer ksec1 10 kday integer ksec1 11 khour integer ksec1 12 kminute integer ksec1 13 kMasterTableNumber integer ksec1 14 64 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Attribute Type Description kMasterTableVersion integer ksecl 15 ksubcente
7. 0 23 minute integer 0 59 second integer 0 59 Table 4 12 Time data structure 37 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Wind Data The wind type data type contains the wind speed and wind direction see table 4 13 The routine init_wind sets the wind vector to missing The routine print_wind may be used to print the wind vector The routine test_wind tests the validity of the wind specification see also the cell process flag Attribute Type Description speed real Wind speed dir real Wind direction Table 4 13 Wind data structure Some special data types are introduced for the data quality flags These are discussed below Beam collocation flag The beam_collocation_type data type is used to indicate whether data of the three beams is originating from a single ground station or from multiple ground stations collocated data This is relevant for so called direct readout data from different ground stations which maybe merged into one single product In a WVC e g the fore beam information from one ground station may be combined with the mid and aft beam information from another ground station in order to make a complete WVC The attributes are listed in table 4 14 The routine get beam_collocation converts an integer value to the logical beam collocation structure The routine set_beam_collocation converts a logical beam collocation struc
8. 1 0 16 Dec 2008 Anton Verhoef Modified according to DRI comments 1 1 Jan 2010 Anton Verhoef Removed a few typo s and corrected some of the diagrams in the appendices for AWDP version 1 1 2 0 Aug 2010 Anton Verhoef Modified for AWDP version 2 0 added section 3 5 3 changed sections 2 3 2 3 4 2 4 Chapter 9 and Appendix B4 2 0 01 Nov 2010 Anton Verhoef Modified according to DRI comments 22 Jun 2013 Anton Verhoef Version for AWDP version 2 2 2 3 Feb 2014 Anton Verhoef Version for AWDP version 2 3 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Contents CELOD D HAH hro EEO E NEO E E E EN E 1 PREEA GE D E A T EE E E AE N EA 4 CHAPTER1 INTRODUCTION seessesecssececssecesesecsscocessoceesseceessecsscceessoceesoecessoeesscoeesseceessecsssseessseessesee 5 1 1 AMSAND SCOPE rtasi A a AE A A EE A OA 5 1 2 DEVELOPMENT ORAWDP arnee e r E E ea A O E eRe N i cewsthee 5 1 3 TESTING AW DP AAA E AE A A E E AE 6 1 4 USER MANUAL AND REFERENCE GUIDE sccccssssecesssececssseececsueeeceesueeecsesaeescseeeesesaeeecsesaeeseneeeenes 6 1 5 COINA INH N LOIRET E T Se devbieey saves aghorn 6 CHAPTER2 AWDP USER MANUAL eeeessecesssecsscceessocecssecesccecssoceesseoeessecescoecssccecsseceessecessseessoseessesee 7 2 1 WHY USING THE AWDP PROGRAM crnini iirin ai e iaae iiie a Es a ieas 7 2 2 MODES OP USING AW DP fes iriden eeen Seach e aaas Reabeeb panded i
9. 25 km and 12 5 km cell spacing execs awdp_run f ascat_20070426_test_250 11_bufr mon calval nwpfl nwpflist execs awdp_run f ascat_20070426_test_125 11_bufr mon calval nwpfl nwpflist The result should be two ASCAT level 2 files in BUFR format called ascat_20070426_095102_metopa_02681_srv_o_250_ovw 12_bufr and ascat_20070426_095100_metopa_02681_srv_o_125_ovw 12_bufr respectively Figure 2 3 shows the global coverage of the test run on 25 km The colours indicate the magnitude of the wind speed as indicated by the legend The result on 12 5 km should be very similar to this Directory awdp tests also contains an ERS BUFR file in ESA format called scatt_20070426_test_250 11 bufr in ESA BUFR format The data are from the same date as the ASCAT data in this directory and they can be processed using the same ECMWF files execs awdp_run f scatt_20070426_test_250 11_bufr mon nwpfl nwpflist The result should be an output file in ASCAT BUFR format called scatt_20070426_063627_ers2 00000 _srv_o_250_ovw 12_bufr 0 3 6 J 12 15 18 21 24 255 m s Figure 2 3 Global coverage of the test run Wind speed results for the 25 km product are shown 20 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and PR ae Reference Guide Date _ February 2014 Directory genscat support bufr contains a test program named test_modules It is invoked by the g
10. 4 Manual compilation and linking Compilation and linking of AWDP under Linux or Unix is done in three steps 1 Set the compiler environment variables according to the choice entered on request This can be done by running the appropriate use_ scripts in directory genscat 2 Go to directory genscat and type make 3 Go to directory awdp and type make to produce the executable awdp in directory awdp src Before activating the make system some environment variables identifying the compiler should be set These variables are listed in table 2 4 The environment variables in table 2 4 can be set by using one of the use_ scripts located in directory genscat Table 2 5 shows the properties of these scripts The scripts are available in Bourne shell extension bsh and in C shell extension csh Note that if one of the environment variables is not set the default 90 and cc commands on the Unix platform will be invoked Note that in the top directory a script called InstallAWDP is provided that asks the user which compiler he wants to use and invokes the appropriate use_ script step 1 above after which the compilation in the genscat and awdp directories is performed steps 2 and 3 above Variable Function SGENSCAT_F77 Reference to Fortran 77 compiler SGENSCAT_F90 Reference to Fortran 90 compiler SGENSCAT_CC Reference to C compiler SGENSCAT_LINK Reference to linker for Fortran objects SGENSCAT_CLINK Reference to linker for
11. C objects SGENSCAT_SHLINK _ Reference to linker for shared objects Table 2 4 Environment variables for compilation and linking 13 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and ee ae Reference Guide Date February 2014 Script Fortran C Remarks compiler compiler use_g95 g95 gcc GNU compilers by A Vaught use_gfortran gfortran gcc GNU GCC 4 0 compiler collection use_ifort ifort ice Intel Fortran and C compilers use_pgf90 pgf90 gcc Portland Fortran compiler Table 2 5 Properties of the use_ scripts Example To select the GNU g95 compiler under Bourne Bash or Korn shell type use_g95 bsh the dot being absolutely necessary in order to apply the compiler selection to the current shell Under C shell the equivalent command reads source use_g95 csh If the user wants to use a Fortran or C compiler not included in table 2 6 he can make his own version of the use_ script or set the environment variables for compilation and linking manually AWDP is delivered with a complete make system for compilation and linking under Unix or Linux The make system is designed as portable as possible and system dependent features are avoided As a consequence some tasks must be transferred to shell scripts The make system consists of two parts one for AWDP and one for genscat The genscat part should be run first For compilation and linking of the genscat part the user should move to the genscat directory and si
12. P is now ready for use provided that the environment variables discussed in section 2 3 5 have the proper settings See also sections 2 4 and 2 5 for directions on how to run AWDP 2 3 1 Directories and files All code for AWDP is stored in a file named AWDP lt version gt tar gz that is made available in the framework of the NWP SAF project This file should be placed in the directory from which AWD P is to be run After unzipping with gunzip AWDP lt version gt tar gz and untarring with tar xf AWDP lt version gt tar the AWDP package is extracted in subdirectories awdp and genscat which are located in the directory where the tar file was located Subdirectories awdp and genscat each contain a number of files and subdirectories A copy of the release notes can also be found in the directory awdp docs Tables 2 1 and 2 2 list the contents of directories awdp and genscat respectively together with the main contents of the various parts Depending on the distribution more directories may be present but these are of less importance to the user Name Contents doc Documentation including this document execs Link to awdp executable shell script for running AWDP sre Source code for AWDP program and supporting routines test Example BUFR and GRIB input files for testing purposes Table 2 1 Contents of directory awdp Name Contents ambrem Ambiguity removal routines ambrem twodvar KNMI 2DVAR ambiguity removal routines
13. Table 4 28 provides an overview of the routines and their calls in this module 44 NWP SAF AWDP User Manual and Reference Guide Doc ID Version Date NWPSAF KN UD 005 23 February 2014 Routine Call Description bayesianIcemodel ice_mode Implementation of the Bayesian ice model calc_aAve bayesianIcemodel Calculate space time averaged A parameter calc_aSd bayesianIcemodel Calculate standard deviation of A parameter calcIceCoord bayesianIcemodel Calculate ice coordinates and distance to ice line calclcelineParms nonbayesianlceModel Calculate distance to ice line from given o s calcIceCoord calc_pIceGivenX bayesianIcemodel Calculate a posteriori ice probability calcSubClass bayesianIcemodel Determine the sub class of the ice pixel getPx updatelcePixel Calculate a priori ice probability iceGMF not used Calculate the a values from the ice coordinates iceLine iceGMF not used Calculate the ice line origin and slope iceMap2scat bayesianIcemodel Update cell data structure with information in ice map ice_model AWDP Main routine of ice screening nonbayesianIceModel _ ice_mode Implementation of the basic ice model without history scat2iceMap bayesianIcemodel Update the ice map with the information in cell data setCmix bayesianIcemodel Compute geophysical ice model tolerance parameter smooth bayesianIcemodel Spatial smoothing of the a posteriori probability updatelcePixel scat2iceMap Update one ice pixel
14. VV create LUT C VV Table 5 1 Routines in module inversion Routine Call normalise_conedist_ers_ascat calc_kp_ers_ascat calc_geoph_noise_ers_ascat normalise_conedist_prescat_mode get_ers_noise_estimate check_ers_ascat_inversion_data check_wind_solutions_ers_ascat remove_one_solution calc_probabilities AWDP normalise_conedist_ers_ascat calc_kp_ers_ascat AWDP normalise_conedist_prescat_mode see B 1 AWDP check_wind_solutions_ers_ascat AWDP Table 5 2 Routines of module post_inversion To establish the MLE function 1 the radar cross section according to the GMF aur must be calculated This is done in routine calc_sigma0 The GMF used is read as a Look Up Table LUT from a binary file The value for O ine is obtained from interpolation of this table The 47 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 interpolation is done via symbolic routine INTERPOLATE which is set to interpolateld interpolate2d interpolate2dv or interpolate3d depending on the type of interpolation needed For C band at VV polarization the GMF CMODx see Hersbach Stoffen and de Haan 2007 is given in analytical form routines calc_sigma0_cmodxxx If a C band LUT is not present it will be created by routine create LUT _C_VV This routine calls one of the routines calc_sigma0_cmodxxx that contain the analytical expressions of the CMOD4 or CMO
15. band Radar wavelength at about 5 cm ERS European Remote Sensing satellites ECMWF European Centre for Medium range Weather Forecasts EUMETSAT European Organization for the Exploitation of Meteorological Satellites genscat generic scatterometer software routines GMF Geophysical model function HIRLAM High resolution Local Area Model KNMI Koninklijk Nederlands Meteorologisch Instituut Royal Netherlands Meteorological Institute Ku band Radar wavelength at about 2 cm Llb Level 1b product LSM Land Sea Mask LUT Look up table Metop Meteorological Operational Satellite MLE Maximum Likelihood Estimator MSS Multiple Solution Scheme NRCS Normalized Radar Cross Section o NWP Numerical Weather Prediction OSI Ocean and Sea Ice PFS Product Format Specification native Metop file format QC Quality Control RFSCAT Rotating Fan beam Scatterometer RMS Root Mean Square SAF Satellite Application Facility SSM Surface Soil Moisture SST Sea Surface Temperature WVC Wind Vector Cell also called node or cell Table D 1 List of acronyms 101
16. function Unpack_ControlVector Jo Unpack of control vector Pack_ControlVector Jo Pack of control vector or its gradient Uncondition Jo Several transformations of control vector Uncondition_adj Jo Adjoint of Uncondition Minimise Do2DVAR TwoDvar Minimization DumpAnalysisField Do2DVAR Write analysis field to file Table 6 12 Routines of module CostFunction 6 4 5 Adjoint method The minimization of cost function is done with a quasi Newton method Such a method requires an accurate approximation of the gradient of the cost function The adjoint method is just a very economical manner to calculate this gradient For introductory texts on the adjoint method and adjoint coding see e g Talagrand 1991 Giering 1997 For detailed information on the adjoint 56 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Teea aa Reference Guide Date February 2014 model in 2DVAR see Vogelzang 2007 6 4 6 Structure Functions Module StrucFunc contains the routines to calculate the covariance matrices for the stream function y and the velocity potential y Its routines are listed in table 6 13 Routine Call Description SetCovMat Do2DVAR Calculate the covariance matrices InitStrucFunc SetCovMat Initialize the structure functions StrucFuncPsi SetCovMat Calculate w StrucFuncChi SetCovMat Calculate y Table 6 13 Routines of module StrucFunc Routine nitStrucF unc sets the structure function parameters to a default
17. inversion Inversion and quality control routines main Dummy subdirectory to facilitate the make system support General purpose routines sorted in subdirectories support BFGS Minimization routines needed in 2DVAR support bufr BUFR tables in subdirectory and file handling routines support Compiler_Features Compiler specific routines mainly command line handling support convert Conversion between wind speed direction and u and v 11 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Name Contents support datetime Date and time conversion routines support ErrorHandler Error handling routines support file File handling routines support grib GRIB file handling routines support num Numerical definitions and number handling routines support pfs PFS file handling routines support singletonfft FFT routines needed in minimization support sort Sorting routines Table 2 2 Contents of directory genscat Directories awdp and genscat and their subdirectories contain various file types e Fortran 90 source code recognizable by the F 90 extension e C source code recognizable by the c extension e Files and scripts that are part of the make system for compilation like Makefile_thisdir Makefile use_ Objects txt and Set_Makeoptions see 2 3 4 for more details e Scripts for the execution of AWDP in directory awdp execs e Look up tables and BUFR tables needed by AW
18. or Product Format Specification PFS native Metop format BUFR input may be provided using the BUFR templates for ERS or ASCAT output is always written using the ASCAT BUFR template Besides the nominal 25 km and 12 5 km products AWDP also has the capability to generate a coastal wind product where the backscatter data from the level 1b files are replaced by box averaged backscatter values from the full resolution level 1 ASCAT product SZF data This mode of operation produces winds that are closer to the coast than the winds from the nominal level 1b data which contain backscatter values that are averaged using a Hamming filter see Verhoef et al 2012 Currently 2013 the SZF data are not available for users in near real time but only off line from the EUMETSAT Data Centre Apart from the ASCAT input data AWDP needs Numerical Weather Prediction NWP model winds as a first guess for the Ambiguity Removal step These data need to be provided in GRIB edition 1 or 2 1 2 Development of AWDP AWD P is developed within the Numerical Weather Prediction Satellite Application Facility NWP SAF and Ocean and Sea Ice Satellite Application Facility OSI SAF programs as code which can be run in an operational setting The coding is in Fortran 90 and has followed the procedures specified for the NWP SAF Special attention has been paid to robustness and readability AWDP DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Teea aa Referenc
19. or second level calling trees in the next figures Black boxes with light text indicate genscat routines NWP SAF AWDP User Manual and Doc ID NWPSAF KN UD 005 Version 2 3 Reference Guide Date _ February 2014 gt read_bufr_file GetElapsedSystemTime set_BUFR_fileattributes open_BUFF_file get_BUFR_nr_of_messages get_BUFR_message gt ers_bufr_to_row_data init_cell gt get_wvc_quality BufrReal2int get_beam_collocation set_knmi_flag test_cell gt ymd2julian julian2ymd ascat_bufr_to_row_data init_cell gt get_wvc_quality BufrReal2lnt get_beam_collocation get_kp_estim_qual test_cell gt close_BUFR_file ymd2julian Figure A 2 Calling tree for routine read_bufr_file first level 74 AWDP User Manual and Doc ID NWPSAF KN UD 005 Version 2 3 NWP SAF Reference Guide Date February 2014 gt read_pfs_file GetElapsedSystemTime get_lun open_pfs_ascat_file read_pfs_ascat_data_record get_pfs_ascat_grid_node get_beam_collocation init_cell gt get_kp_estim_qual test_beam init_beam WVC_ Orientation test_cell gt close_pfs_ascat_file free_lun ymd2julian Figure A 3 Calling tree for routine read_pfs_file first level preprocess GetElapsedSystemTime GetSortIndex merge_rows copy_cell set_knmi_flag init_cel
20. print the bit values of the flag Attribute Description satellite_id sat_instruments Invalid satellite id Invalid satellite instrument id sat_motion Invalid satellite direction of motion time Invalid date or time specification latlon Invalid latitude or longitude pixel_size_hor Invalid cell spacing node_nr Invalid across track cell number beam 3 Invalid data in one of the beams model_wind Invalid background wind ambiguity Invalid ambiguities selection Invalid wind selection Table 4 17 Cell process flag bits Fortran Table 4 18 provides an overview of all routines and their calls in module awdp_data Routine Call Description copy_cell Copy all information from one cell into another get_beam_collocation init cell Convert integer beam collocation to logical structure 39 AWDP User Manual and PocID NWPSAF KN UD 00 NWP SAF Version 2 3 Reference Guide Date February 2014 Routine Call Description get kp _estim_qual init beam Convert integer K estimate quality to logical structure get_wvc_quality init_cell Convert integer WVC quality to logical structure init_ambiguity Initialise ambiguity structure init_beam init cell Initialise beam structure init _cell Initialise cell structure init_full_res init cell Initialise full resolution structure init_icemodel init cell Initialise ice model structure init nwp_stress_param init cell Initialise NWP stress parameters structure init_pro
21. real Mean value of full res values sigma0_mid real Mean value of full res values sigma0_sq_ mid real Sum of squares land _ frac mid real Mean value of full res values count_aft integer Number of full res aft beams used incidence _aft real Mean value of full res values azimuth _aft real Mean value of full res values sigma0_aft real Mean value of full res values sigma0_sq_aft real Sum of squares land_frac_aft real Mean value of full res values Table 4 8 Full res data structure Ice model data The icemodel type contains information related to the ice screening The attributes are listed in table 4 9 The routine init_icemodel sets the ice model data to missing values The routine print_icemodel may be used to print the ice data Attribute Type Description class integer Code for WVC being ice or wind il integer Coordinate on the ice map jj integer Coordinate on the ice map a real Ice coordinate b real Ice coordinate 36 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Attribute Type Description Cc real Ice coordinate dice real Distance to the ice line wind_sol integer Wind solution to be used Table 4 9 Ice model data structure NWP stress parameter data The nwp_ stress param type data type contains information relevant for the ice screening and wind stress calculations stress calculation is not yet implemented in AWDP The attribu
22. routine PrintCell second level 81 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 gt calclceCoord calclcelineParms calcPoly3 Figure A 16 Calling tree for routine calcIceCoord second level updatelcePixel ExpandDateTime Figure A 17 Calling tree for routine updatelcePixel second level 82 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and es D Reference Guide Date February 2014 Appendix B1 Calling tree for inversion routines The figures in this appendix show the calling tree for the inversion routines in genscat All routines are part of genscat as indicated by the black boxes An arrow before a routine name indicates that this part of the calling tree is a continuation of a branch in a previous figure The same arrow after a routine name indicates that this branch will be continued in a following figure 83 Doc ID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Version 2 3 Reference Guide Date February 2014 gt invert_one_wvc init_inv_settings_to_default init_inv_output print_message check_input_data print_input_data_of_inversion my_exit print_message convert_sigma_to_zspace calc_normalisation calc_var_s0 find_minimum_cone_dist my_min my_average my_max get_indices_lowest_local_minimum my_index_max print_message do_parabolic_winddir_search get_parabolic_min
23. rows according to their acquisition date and time or the wind vector solutions according to their probability 33 NWPSAF KN UD 005 23 February 2014 Doc ID Version Date AWDP User Manual and Reference Guide NWP SAF 4 3 Module design for process layer The process layer consists of the modules awdp data awdp_bufr awdp_pfs awdp_prepost awdp_grib awdp_inversion awdp_icemodel and awdp_ambrem The routines present in these modules are described in the next sections 4 3 1 Module awdp_data The module awdp data contains all the important data types relevant for the processing Elementary data types are introduced for the most basic data structures of the processing These are e g wind type and time type Using these data types and of course the standard types as integer real etc more complex composed data types are derived Examples are beam _type ambiguity_type cell_type and row_type A complete description of all types is given below The attributes of all these types have intentionally self documenting names Ambiguity data The ambiguity type data type contains information on an individual ambiguity wind vector solution The attributes are listed in table 4 5 The routine init_ambiguity sets all ambiguity data to missing The routine print_ambiguity may be used to print all ambiguity data Attribute Type Description wind wind_type Wind vector solution prob real Probability of wind vector solutio
24. value 6 4 7 Minimization The minimization routine used is LBFGS This is a quasi Newton method with a variable rank for the approximation of the Hessian written by J Nocedal A detailed description of this method is given by Liu and Nocedal 1989 Routine LBFGS is freeware and can be obtained from web page http www netlib org opt index html file Lbfgs_um shar The original Fortran 77 code has been adjusted to compile under Fortran 90 compilers Routine LBFGS and its dependencies are located in module BFGSMod F90 in directory genscat support BFGS Table 6 14 provides an overview of the routines in this module Routine LBFGS uses reverse communication This means that the routine returns to the calling routine not only if the minimization process has converged or when an error has occurred but also when a new evaluation of the function and the gradient is needed This has the advantage that no restrictions are imposed on the form of routine Jt calculating the cost function and its gradient The formal parameters of LBF GS have been extended to include all work space arrays needed by the routine The work space is allocated in the calling routine minimise The rank of LBFGS affects the size of the work space It has been fixed to 3 in routine minimise because this value gave the best results lowest values for the cost function at the final solution Routine Call Description LBFGS minimise Main routine LB LBFGS Printing of ou
25. which AWDP has been tested However the program is designed to run on any Unix Linux based computer platform with a Fortran compiler and a C compiler The equivalent of a modern personal computer will suffice to provide a timely NRT wind product AWDP requires about 100 150 MB disk space when installed and compiled Platform Fortran compiler C compiler Fedora Linux work station Portland pgf90 GNU gcc GNU g95 GNU gfortran SunOS Unix Sun Fortran Sun C SGI Altix Intel Fortran compiler Intel C compiler Table 3 1 Platform and compiler combinations for which AWDP has been tested AWDP may also run in other environments provided that the environment variables discussed in section 2 2 are set to the proper values and that the BUFR library is properly installed For Windows a Linux environment like Wubi is needed 3 5 Details of functionality 3 5 1 BUFR IO and coding Data sets of near real time meteorological observations are generally coded in the Binary Universal Form for Representation BUFR BUFR is a machine independent data representation system but it contains binary data so care must be taken in reading and writing these data under different operating systems A BUFR message record contains observational data of any sort in a self descriptive manner The description includes the parameter identification and its unit decimal and scaling specifications The actual data are in binary code The meta data are stored in BUFR
26. 2134 Antenna Beam Azimuth Degree 52 021062 Backscatter dB 53 021063 Radiometric Resolution Noise Value 54 021158 ASCAT Kp Estimate Quality Code Table 55 021159 ASCAT Sigma 0 Usability Code Table 56 021160 ASCAT Use Of Synthetic Data Numeric 57 021161 ASCAT Synthetic Data Quality Numeric 58 021162 ASCAT Satellite Orbit And Attitude Quality Numeric 59 021163 ASCAT Solar Array Reflection Contamination Numeric 60 021164 ASCAT Telemetry Presence And Quality Numeric 61 021165 ASCAT Extrapolated Reference Function Numeric 62 021166 ASCAT Land Fraction Numeric 63 025060 Software Identification Numeric 64 025062 Database Identification Numeric 65 040001 Surface Soil Moisture Ms 66 040002 Estimated Error In Surface Soil Moisture 67 021062 Backscatter dB 68 021151 Estimated Error In Sigma0 At 40 Deg Incidence Angle dB 69 021152 Slope At 40 Deg Incidence Angle dB Degree 70 021153 Estimated Error In Slope At 40 Deg Incidence Angle dB Degree 71 021154 Soil Moisture Sensitivity dB 72 021062 Backscatter dB 73 021088 Wet Backscatter dB 74 040003 Mean Surface Soil Moisture Numeric 75 040004 Rain Fall Detection Numeric 76 040005 Soil Moisture Correction Flag Flag Table 77 040006 Soil Moisture Processing Flag Flag Table 78 040007 Soil Moisture Quality 79 020065 Snow Cover 80 040008 Frozen Land Surface Fraction 81 040009 Inundation And Wetland Fraction 82 040010 Topographic Complexity 83 025060 Software Identification Numeric 84 001032 Generati
27. 3 Conventions for the wind direction 48 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Chapter 6 Ambiguity Removal module 6 1 Ambiguity Removal Ambiguity Removal AR schemes select a surface wind vector among the different surface wind vector solutions per cell for the set of wind vector cells in consideration The goal is to set a unique meteorological consistent surface wind field The surface wind vector solutions per cell simply called ambiguities result from the wind retrieval process step Whenever the ambiguities are ranked a naive scheme would be to select the ambiguity with the first rank e g the highest probability the lowest distance to the wind cone In general such a persistent first rank selection will not suffice to create a realistic surface wind vector field scatterometer measurements tend to generate ambiguous wind solutions with approximately equal likelihood mainly due to the 180 invariance of stand alone scatterometer measurements Therefore additional spatial constraints and or additional external information are needed to make sensible selections A common way to add external information to a WVC is to provide a background surface wind vector The background wind acts as a first approximation for the expected mean wind over the cell In general a NWP model wind is interpolated for this purpose Whenever a background wind is set
28. 4 2 The most important classes of modules are related to the inversion processing step Chapter 5 the Ambiguity Removal step Chapter 6 the BUFR file handling Chapter 8 and the GRIB file handling Chapter 9 The genscat modules are located in subdirectory genscat In addition genscat contains a large support class to convert and transform meteorological geographical and time data to handle file access and error messages sorting and to perform more complex numerical calculations on minimization and Fourier transformation Many routines are co developed for ERS ASCAT and SeaWinds data processing Module class Tasks Description Ambrem Ambiguity Removal 2DVAR and other schemes see Chapter 6 Inversion Wind retrieval Inversion in one cell see Chapter 5 IceModel Ice screening Uses ice line and wind cone for ice discrimination Support BUFR support BufrMod based on ECMWF library PFS support Reading of PFS files GRIB support gribio_module based on ECMWF library FFT minimization Support for 2DVAR Error handling Print error messages File handling Finding opening and closing free file units Conversion Conversion of meteorological quantities Sorting Sorting of ambiguities to their probability Date and time General purpose Table 4 2 genscat module classes 4 1 3 Data Structure Along track the ASCAT swath is divided into rows Within a row across track the ASCAT orbit is divided into cells also called Wind Vector Cells WV
29. BUFR_TABLES variable guides AWDP to the BUFR tables needed to read the input and write the output The GRIB_DEFINITION_PATH variable is necessary for a proper functioning of the GRIB decoding software The variable SINVERSTON_LUTSDIR should point to a directory containing some look up tables extension asc that are used by the inversion software The necessary tables are delivered with genscat The variable SLUT_FILENAME_C_VV points AWDP to the correct C band GMF lookup table at VV polarisation It should contain a file name including a valid path If the file does not exist it will be created when the inversion is invoked for the first WVC In order to prevent confusion it is advised to use standard file names lt path gt cmod5 dat lt path gt cmod5_5 dat lt path gt cmod5_n dat or lt path gt cmod6 dat since the inversion software uses the file name to determine which CMOD version is used 2 4 Command line options The AWDP program is started from directory awdp execs with the command awdp options modes f lt BUFR PFS file gt nwpfl lt file gt with lt gt indicating obligatory input and indicating non obligatory input The following command line options are available f lt input file gt Process a BUFR or PFS input file with name input file AWDP detects if the input file is in BUFR format If not it attempts to read the input as PFS file The BUFR input f
30. Coefficients TDV Init Set Helmholz transformation coefficients Set_ CFW TDV_Init Set cost function weights TDV_Exit ExitTwodvarmodule Deallocate memory InitObs2dvar BatchInput2DVAR Allocation of observations array BatchOutput2DVAR DeallocObs2dvar BatchOutput2DVAR Deallocation of observations array InitOneObs2dvar InitObs2dvar Initialization of single observation TestObs2dvar Do2DVAR Test single observation Prn2DVARQualFlag Do2DVAR Print observation quality flag set2DVARQualFlag TestObs2DVAR Convert observation quality flag to integer get2DVARQualFlag not used Convert integer to observation quality flag Table 6 10 Routines in module TwoDvarData The quality status of an instance of Obs2dvarType is indicated by the attribute QualFlag which is an instance of TwoDvarQualFlagType The attributes of this flag are listed in table 6 11 Attribute Description missing Flag values not set wrong Invalid 2DVAR process Lat Invalid latitude Background Invalid background wind increment Ambiguities Invalid ambiguity increments Selection Invalid selection Analyse Invalid analysis wind increment Cost Invalid cost function specification gradient Invalid gradient specification weights Invalid interpolation weights grid Invalid grid indices Table 6 11 Attributes of 2DVAR observation quality flag 55 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and PR ae Reference Guide Date _ February 2014 6 4 3 Reformulation a
31. Compiler_Features for handling some compiler specific issues mainly with respect to command line argument handling The Makefile in this directory compiles on of the available source files depending on the Fortran compiler used Subdirectory convert contains module convert for the conversion of meteorological and geographical quantities e g the conversion of wind speed and direction into u and v components and vice versa Subdirectory datetime contains module DateTimeMod for date and time conversions AWDP only uses routines GetElapsedSystemTime for calculating the running time of the various processing steps and julian2ymd and ymd2julian for conversion between Julian day number and day month and year Module DateTimeMod needs modules ErrorHandler and numerics Subdirectory ErrorHandler contains module ErrorHandler for error management This module is needed by module DateTimeMod Subdirectory file contains module LunManager for finding opening and closing free logical units in Fortran AWDP uses only routines get lun and free lun for opening and closing of a logical unit respectively Subdirectory num contains module numerics for defining data types and handling missing values for instance in the BUFR library This module is needed by many other modules Subdirectory pfs contains module pfs_ascat for opening reading and closing of files in PFS format Subdirectory sort finally contains module SortMod for sorting the
32. Cs or nodes This division in rows and cells forms the basis of the main data structures within the AWDP package In fact both the input and the output structure are one dimensional arrays of the row data structure row_type These arrays represent just a part of the swath Reading and writing decoding and encoding ASCAT BUFR files corresponds to the mapping of a BUFR message to an instance of the row_type and 30 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and es D Reference Guide Date February 2014 vice versa The main constituent of the row_type is the cell data structure cell_type see figure 4 2 Since most of the processing is done on a cell by cell basis the cell_type is the pivot data structure of the processor row_type cell_type ambiguity_type Figure 4 2 Schematic representation of the nested data definitions in the row_type data structure The o related level 1b data of a cell are stored in a data structure called beam_type Every cell contains three instances of the beam_type corresponding to the fore middle and aft beams A cell may also contain an array of instances of the ambiguity_type data structure This array stores the results of a successful wind retrieval step the wind ambiguities level 2 data Details of all the data structures and methods working on them are described in the next sections 4 1 4 Quality flagging and error handling Important aspects of the data processing are to c
33. DP e Files with information like Readme t xt After compilation the subdirectories with the source code will also contain the object codes of the various modules and routines 2 3 2 Installing the BUFR library AWDP needs the ECMWF BUFR library for its input and output operations Only ECMWF is allowed to distribute this software It can be obtained free of charge from ECMWF at the web page http www ecmwf int products data software bufr html The package contains scripts for compilation and installation The reader is referred to this site for assistance in downloading and installing the BUFR Library Directory genscat support bufr contains the shell script make bufr lib It unzips untars and compiles the BUFR library file which is downloaded from ECMWF and placed into this directory This script is part of the genscat make system and it is automatically invoked when compiling genscat The current version is tested with BUFR version 000400 earlier versions between 000240 and 000387 can also be used Note that library versions 000388 and 000389 are not supported BUFR file handling at the lowest level is difficult to achieve Therefore some routines were coded in C These routines are collected in library bufrio see also section 8 4 Its source code is located in file bufrio c in subdirectory genscat support bufr Compilation is done within the genscat make system and requires no further action from the user see 2 3 4 2 3 3 In
34. DS algorithm There is a parameter in the inversion settings type that is used to determine which CMOD function is to be used Routines get lun and free lun from module LunManager in subdirectory genscat support file are needed when reading and creating the LUTs Note that module post_inversion uses some tables for the normalisation of MLEs and noise values These tables are read from ASCII files which are present in direction genscat inversion The environment variable INVERSION_LUTSDIR should contain the proper directory name 5 3 Antenna direction The output wind direction of inversion routines are generally given in the meteorological convention see table 5 3 The inversion routine uses a wind direction that is relative to the antenna direction The convention is that if the wind blows towards the antenna then this relative wind direction equals to 0 Therefore it is important to be certain about the convention of your antenna azimuth angle For ERS and ASCAT the radar look angle antenna angle or simply azimuth equals 0 if the antenna is orientated towards the south The radar look angle increases clockwise Therefore the antenna angle needs a correction of 180 degrees Meteorological Oceanographic Mathematical u v Description 0 180 270 0 1 Wind blowing from the north 90 270 180 1 0 Wind blowing from the east 180 0 90 0 1 Wind blowing from the south 270 90 0 1 0 Wind blowing from the west Table 5
35. Flag Figure B2 3 Calling tree for AR routine nitObs2dvar 87 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 gt Do2DVAR TestObs2dvar set2DVARQualFlag Prn2DVARQualFlag SetCovMat StrucFuncPsi StrucFuncChi SingletonFFT2d gt Jt gt Minimise Jt gt LBFGS daxpy ddot LB1 MCSRCH MCSTEP TestObs2dvar set2DVARQualFlag DumpAnalysisField Figure B2 4 Calling tree for AR routine Do2DVAR Unpack_ControlVector Uncondition SingletonFFT2d gt Uncondition_adj SingletonFFT2d gt Pack_ControlVector Figure B2 5 Calling tree for AR routine Jt calculation of cost function 88 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 SingletonFFT2d SFT_PrimeFactors SFT_Permute SFT_PermuteSinglevariate SFT_PermuteMultivariate SFT_Base2 SFT_Base3 SFT_Base4 SFT_Base5 SFT_BaseOdd SFT_Rotate Figure B2 6 Calling tree for AR routine SingletonF FT2D 89 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Appendix B3 Calling tree for BUFR routines The figures in this appendix show the calling tree for the BUFR file handling routines in genscat Routines in black boxes are part of genscat Routines in grey boxes with names complete
36. LITY 2 ccescSccdeusnts os nierenee ietin e EE e e E EEE EEE EE 23 3 5 BUFR lO and cod gecene A E E a REAR E eee 23 SID Produc re OU O T e a E E E T ETTE S ESET EE N GE 24 333 Use amp of full resolution dataserie sianid aeaaaee asa Aae iaa aa aaa Saan EEE A 24 3 5 4 WVC triplet completion and row merging eeeeeeeeeeereserrrrererisrsrirrerersrsrserse 24 SDD Quality CONTO oieee i iad aae ia a E ine Ee a EE e an eea aai 25 BDO ANVCNSION e hanee e o A A E E O a eE EEE E 25 E A EENG LA 1 EEEN E E E E i Mes wortess 25 3 3 8 AMDIguILy REMOVAL eenei arao araia iot a iae E a Ea a a o E EE iE 26 3 99 Monilorin oa anae pai a e Ae a e ie a a e a aai 26 3 6 DETAILS OF PERFORMANCE cn aiii ieri E E E EE iiae EE iiia E aTa 26 CHAPTER 4 PROGRAM DESIGN e sssseessecesssecesssecsscceesseceessecssccecscoeesseceesoecsscoecssoceesseceessecsssseessoseessee 28 4 1 TOP LEVEE DESIGN catia a a a decane ea oria na eeestis 28 Ll Main Program moe eE EE Ae EEE ENE A IE EAE A E E E RE RRA 28 4 1 2 Layered model structure ccccccesccscsescsssesceseeseesetseesecceescsessesecaesseesecaeesecaeeeeceaeeseesecaeseeeneeren 29 P O IE SDA 1 7 111 Coes re AA E A aaa voce ng eh itt Mie oh hae ee eked a Staal ke al 30 4 1 4 Quality flagging and error NAandling ccccccccccccccecccecceseescesesseesecneeeecuseesenseeseeecieeeeenseesenseesentees 31 FAS SVEPDOSU a I dos cast cote case boos A E E TEE T E 31 4 2 MODULE DESIGN FOR GENSCAT LAYER i eini konoa E e o a a A
37. NWP SAF Satellite Application Facility for Numerical Weather Prediction Document NWPSAF KN UD 005 Version 2 3 February 2014 AWDP User Manual and Reference Guide Anton Verhoef Jur Vogelzang Jeroen Verspeek and Ad Stoffelen KNMI De Bilt the Netherlands The EUMETSAT Network Satelite Application Factities Numerical Weather Prediction P Royal Netherlands lt M t Offi rr ECMWF KOA Meteorological Institute Ae e ce Ste Ministry of Transport Public Works and Water Management METEO FRANCE Toujours un temps d avance DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and es D Reference Guide Date February 2014 AWDP User Manual and Reference Guide KNMI De Bilt the Netherlands This documentation was developed within the context of the EUMETSAT Satellite Application Facility on Numerical Weather Prediction NWP SAF under the Cooperation Agreement dated 29 June 2011 between EUMETSAT and the Met Office UK by one or more partners within the NWP SAF The partners in the NWP SAF are the Met Office ECMWF KNMI and M t o France Copyright 2014 EUMETSAT All Rights Reserved Change record Version Date Author changed by Remarks 1 0j Jun 2007 Anton Verhoef First draft 1 0k Oct 2007 Anton Verhoef Adapted for AWDP version 1 0k 1 0 13 Mar 2008 Anton Verhoef Adapted for AWDP version 1 0 13 1 0 14 Oct 2008 Anton Verhoef First version for external review
38. NWPSAF KN UD 005 NWP SAF AWDP User Manual and Gee oe Reference Guide Date _ February 2014 AmbremPreScat AmbremBGclosest BatchMod TwoDvarData BFGSMod SingletonFFT Figure 6 1 Interdependence of the modules for Ambiguity Removal The connections from module ambrem to module BatchMod and from module Ambrem2DVAR to convert are not drawn Ambrem2DVAR convert BatchRowType BatchCellType BatchQualFlagType BatchAmbiType Figure 6 2 Schematic representation of the batch data structure BatchType Attribute Type Description NrRows Integer Number of rows in batch Row BatchRowType Array of rows BatchRowType Attribute Type Description RowNr Integer Row number within orbit 51 Doc ID Version Date NWPSAF KN UD 005 23 February 2014 NWP SAF AWDP User Manual and Reference Guide NrCells Integer Number of cells in batch max 76 Cell BatchCellType Array of cells within row BatchCellType Attribute Type Description NodeNr Integer Node number within orbit row lat Real Latitude lon Real Longitude ubg Real u component of background wind vbg Real v component of background wind NrAmbiguities Integer Number of ambiguities Ambi BatchAmbiType Array of ambiguities BatchAmbiType Attribute Type Description selection Integer Index of selected ambiguity uana Real u component of analysis wind vana Real v component of analysis wind f Real C
39. SAF AWDP User Manual and Version 23 Reference Guide Date February 2014 Routine Call Description AllocRowsOnlyAndInitBatch not used InitBatchModule Ambrem Initialization module InitBatch InitBatchRow InitBatchCell InitbatchAmbi AllocRowsAndCellsAndInitBatch InitBatch InitBatchRow InitBatchCell Initialization of batch Initialization of batch rows Initialization of batch cells Initialization of batch ambiguities DeallocBatch Processor Deallocation of batch DeallocBatchRows DeallocBatch Deallocation of batch rows DeallocBatchCells DeallocBatchRows Deallocation of batch cells DeallocBatchAmbis DeallocBatchCells Deallocation of batch ambiguities TestBatch Processor Test complete batch TestBatchRow TestBatch Test complete batch row TestBatchCell TestBatchRow Test batch cell TestBatchQualFlag Processor Print the quality flag getBatchQualFlag not used setBatchQualFlag not used PrnBatchQualFlag not used Table 6 5 Routines of module BatchMod 6 4 The KNMI 2DVAR scheme 6 4 1 Introduction The purpose of the KNMI 2DVAR scheme is to make an optimal selection provided the modelled likelihood of the ambiguities and the modelled uncertainty of the background surface wind field First an optimal estimated surface wind vector field analysis is determined based on variational principles This is a very common method originating from the broad discipline of Data Assimilation The optimal surface wind vector field is call
40. There are two important data structures defined in this module The first contains all relevant data of one pixel on the ice map IcePixel The second one contains basically a two dimensional array 60 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and PR ae Reference Guide Date February 2014 of ice pixels and represents an entire ice map IceMapType This could be either an ice map of the North Pole region or the South Pole region Attribute Type Description alce real A ice parameter alceAves real Average of the A ice parameter aSd real A ice parameter standard deviation class integer Ice class subClass integer Ice subclass sst real Sea surface temperature K pXgiven ce real pXgivenOce real pYgivenlce real pYgivenOce real Pice real A priori ice probability plceGivenX real A posteriori ice probability pliceGivenXave real Average of a posteriori ice probability sumWeightST real Sum of weight factors landmask logical land sea indicator timePixelNow DateTime Date time of measurement timePixelPrev DateTime _Date time of previous measurement Table 7 2 Attributes for the cePixel data type Attribute Type Description nPixels integer Number of pixels for the ice map nLines integer Number of lines for the ice map pole integer Indicator for Northpole or Southpole use_sst integer Use SST value in ice screening tineMapNow DateTime Date time of latest ice map update timeMapPrev DateTime Date time of pr
41. UFR item 88 Also it can output graphical maps of ice model related parameters on an SSM I grid for the North Pole and for the South Pole region Each time the Metop satellite passes over the pole region the corresponding ice map is updated with the new ASCAT data A spatial and temporal averaging is performed in order to digest the new information After the overpass at the end of processing an entire BUFR file the updated information on the ice map is put back into the BUFR structure Optionally graphical maps are plotted which can be controlled by optional input parameters for routine printIceMap The graphical filenames have encoded the North Pole South Pole the date time as well as the parameter name The most important ones are print a file N S yyyymmddhhmmss ppm contains the ice subclass and the a ice parameter on a grey scale for points classified as ice print t file N S yyyymmddhhmmss t ppm contains the ice class print sst file N S yyyymmddhhmmss sst ppm contains the sea surface temparature print_postprob file N S yyyymmddhhmmss postprob ppm contains the a posteriori ice probability Typically at least two days of ASCAT data are needed to entirely fill the ice map with data and give meaningful ice model output Because AWDP handles only one BUFR file at a time a script is needed that calls AWDP several times After each AWDP run a binary restart file is written to disk containing the information o
42. WPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Routine Call Description Do2DVARonBatch DoAmbrem Apply 2DVAR scheme on batch BatchInput2DVAR Do2DVARonBatch Fills the 2DVAR data structure with input BatchOutput2DVAR Do2DVARonBatch Fills the batch data structure with output Set WVC_Orientations BatchInput2DVAR Sets the observation orientation GetBatchSize2DVAR Determine maximum size of batch Table 6 6 Routines of module Ambrem2DVAR These routines are sufficient to couple the 2DVAR scheme to the processor The actual 2DVAR processing is done by the routines of module TwoDvar itself These routines are listed in table 6 7 Figures B2 1 B2 6 show the complete calling tree of the AR routines Routine Call Description InitTwodvarModule Initialization of module TwoDvar Do2DVAR Do2DVARonBatch Cost function minimization PrintObs2DVAR BatchInput2DVAR Print a single 2DVAR observation ExitlwodvarModule ExitAmbremMethod Deallocation of module TwoDvar Table 6 7 Routines of module TwoDvar The Obs2dvarType data type is the main data structure for the observed winds Its attributes are listed in table 6 8 The TDV_Type data type contains all parameters that have to do with the 2DVAR batch grid dimensions sizes and derived parameters These data structures are defined in module TwoDvarData and the routines in this module are listed in table 6 10 Attribute Type Description alpha R
43. _095102_metopa_02681_srv_o_250_ovw 12_bufr 2 5 Scripts Directory awdp execs contains a Bourne shell script awdp_run for running awdp with the correct environment variables The script can be invoked with all valid command line options for awdp In the same directory there is also a script awdp_gui py available This script provides a convenient graphical user interface and builds and runs an AWDP command line depending on settings of available radio buttons check boxes et cetera This script requires Python to be installed on your system It may be necessary to change some of the environment variables set in the top part of the script 2 6 Test data and test programs Directory awdp tests contains two BUFR files for testing the AWDP executable File ascat_20070426_test_250 11_bufr contains ASCAT level 1b data from 26 April 2007 9 51 to 10 29 UTC with 25 km cell spacing The same data but on 12 5 km cell spacing is available in file ascat_20070426_test_125 11_bufr The files ECMWF grib contain the necessary NWP data SST land sea mask and wind forecasts to perform the NWP collocation step The user can test the proper functioning of AWDP using the files in the awdp tests directory To do this first create a small file containing a list of NWP files 19 AWDP User Manual and Doc ID NWPSAF KN UD 005 Version 2 3 NWP SAF Reference Guide Date February 2014 ls 1 ECMWF_200704260000_0 gt nwpflist Then run AWDP on
44. _FILENAME_C_VV is present it will be used to store the GMF A second file with the same name and extension zspace is also generated Note the old GMF files need to be removed if new files need to be generated i e if a different GMF version is requested calval Perform o calibration A calibration of the o values is performed See Verspeek Stoffelen Verhoef and Portablla 2012 for more details Calibration coefficients are applied dependent on the satellite Metop A or B and the level 1 data processing version mss Use the Multiple Solution Scheme for Ambiguity Removal If the Multiple Solution Scheme MSS is switched on AWDP internally works with 144 different solutions for the wind vector If MSS is switched off AWDP calculates two solutions at most MSS is switched off as default armeth lt meth gt Choose ambiguity removal method Valid methods are 1st rank the wind solution with the lowest distance to the GMF residual is selected bgclosest the wind solution closest to the background model wind is selected prescat see section 6 5 2dvar 2DVAR see section 6 4 The default is 2dvar par ana tc varqc ocf research orpm Various options intended for research activities More information can be found in the Fortran code of AWDP and genscat binof lt file gt Write selected data of each WVC to a binary output file Data are written to a binary file lt file gt Thi
45. _GRIB_filelist gt get_from_GRIB_filelist gt Figure B4 4 Calling tree for GRIB file handling routine get_colloc_from_GRIB_filelist dealloc_all_GRIB_messages dealloc_GRIB_message grib_close_file Figure B4 5 Calling tree for GRIB file handling routine dealloc_all_GRIB_messages 93 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Appendix B5 Calling tree for PFS routines The figures in this appendix show the calling tree for the PFS native Metop format file handling routines in genscat All routines are part of genscat as indicated by the black boxes An arrow gt before a routine name indicates that this part of the calling tree is a continuation of a branch in a previous figure The same arrow after a routine name indicates that this branch will be continued in a following figure open_pfs_ascat_file read_rec read_string_from_file get_uint get_str get_num strne skip_nrec skip_rec read_string_from_file get_uint streq Figure B5 1 Calling tree for PFS file handling routine open_pfs_ascat_file read_pfs_ascat_data_record read_string_from_file get_uint Figure B5 2 Calling tree for PFS file handling routine read_pfs_ascat_mdr 94 AWDP User Manual and Doc ID NWPSAF KN UD 005 Version 2 3 NWP SAF Reference Guide Date February 2014 gt get_pfs_ascat_grid_node g
46. _of GRIB_derived_ hour _ integer array Key to information in messages 69 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Attribute Type Description list_of GRIB_par_id integer array Key to information in messages list_of GRIB_vals_sizes integer array Size of data values arrays Table 9 2 Attributes for the grib_file_attr_data data type Attribute Type Description message _pos_in_file integer Position of message in GRIB file message_id integer Message id assigned by GRIB API date real Date when data are valid time real Time when data are valid derived_date real date time 24 derived_time real mod time 24 total_message_size integer Size of message vals_size integer Size of data values array is_decoded logical Status flag nr_lon_points integer Information about grid nr_lat_points integer Information about grid nr_grid_points integer Information about grid lat_of first_gridpoint real Information about grid lat_of _last_gridpoint real Information about grid lon_of first_gridpoint real Information about grid lon_of last_gridpoint real Information about grid lat_step real Information about grid lon_step real Information about grid real_values real array pointer Decoded real data values Table 9 3 Attributes for the grib_message_data data type Attribute Type Description grib_file_attributes grib file attr data GRIB file att
47. a a 32 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 4 2 1 Mod le INVETSION a a a a sab a iaa 32 422 S Moduleambrem serate enana E ETE A e aE EE AE TA beat ata oa a 32 423 Mod le ee od els T a a E a a a teak tec a a aa iea 32 4 24 Module B frmod iia hace eini BS leven Ma a a ea Re i BOR ewe 32 4 2 3 Module gribio module ccccccccccsccsccesesssesesseeseesesseesecceescesessessecseeseceeeeeaeesessecaesecnseeeenaeereaees 33 ADO Support modules ssis nane n e else pet a ea aan tein date ese 33 4 3 MODULE DESIGN FOR PROCESS LAYER csssccessssceceessececsseeececsneeecessaececsesaeeecsueeessesaeeecsesaeeeseeeeeenes 34 4 31 Module awdlp Cat eeeececcesescsesecsseeccuseescseeseesecseesecuceccnsescesaecaeesecaesecceaeecesaecaeesecaeseeseeeneeenees 34 43 2 Module wdp buf rererere E aa EARE E E a eat 40 4 3 3 Module qwap pjsiscconsie Acces aeien enen a e enke e aea a E A S 41 43 4 Module awdlp prepostscicsscscisvcvsincsestussvbin sis scdtanersisetanesendaparsiovtectssberdicsbaplissestatscsbsohecistietesen 42 4 3 3 Mod le wdp grib riencia e oe asc a ia aa e aai i e aias 43 4 3 6 Module awdp inversion oi cccccccccccccccsecceseescesesseesessesseesecseeeecceesceseeseeseseseceeeseeseeseeseeneveeeneeeren 44 4 3 7 Module wdp ambrem c roroi eiieeii oiii e EEE EE EE A Win tve EEA Eia e aaa 44 43 8 Module awdp icemodel snosite nianna henni aade hanid shcpt
48. and fraction calculation in AWDP The land fraction is calculated by scanning all grid points of the land sea mask lying within 80 km from the centre of the WVC Every grid point found yields a land fraction between 0 and 1 The land fraction of the WVC is calculated as the average of the grid land fractions where each grid land fraction has a weight of 1 7 r being the distance between the WVC centre and the model grid point Routine get colloc_from_GRIB filelist returns an interpolated value four surrounding grid points from the GRIB data in the list of files messages for a given GRIB parameter latitude longitude and time The list of messages must contain a sequence of forecasts e g 3 hrs 6 hrs 9 hrs et cetera At least three forecasts need to be provided ideally two lying before the sensing time and one after 68 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 In this diagram the 1 2 and 3 mean the three forecast steps with intervals of three hours between them The is the sensing time The software will perform a cubic time interpolation Note that the 1 2 and 3 in the diagram may correspond to 3 6 and 9 forecasts but also e g to 9 12 and 15 If more forecasts are provided e g like this 1 2 3 4 5 the software will use forecast steps 2 3 and 4 i e it will pick the most usable values by itself If one forecast be
49. ata are processed The ASCAT BUFR format consist of three main sections one section containing level 1b information which is copied from the input data one section containing Surface Soil Moisture SSM level 2 information which is also copied from the input and one section containing level 2 wind data which is calculated in AWDP The ASCAT BUFR data descriptors are listed in Appendix C 22 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and PR ae Reference Guide Date February 2014 3 3 Input specification Input of AWDP is the ASCAT level 1b BUFR or PFS Data Product These products are created by EUMETSAT see WMO 2007 and Figa Saldaria and Wilson 2005 Alternatively the ERS scatterometer wind product in BUFR can be used as input see UK Met Office 2001 It is also possible to reprocess level 2 ASCAT or ERS data in ASCAT BUFR format and treat them as if they are level 1b data To achieve this some command line options need to be set see section 2 4 Apart from the scatterometer data GRIB files containing NWP output with global coverage are necessary for the wind processing At least three wind forecasts with forecast time intervals of 3 hours are necessary to perform interpolation with respect to time and location Apart from this GRIB fields of Sea Surface Temperature and Land Sea Mask are necessary for land and ice masking 3 4 System requirements Table 3 1 shows the platform and compiler combinations for
50. ate rows are merged Quality control Usability of input data is determined Post processing Setting of flags Monitoring Clean up Deallocation of used memory awdp_grib GRIB file handling Interface to genscat support grib Collocation of GRIB data NWP data are interpolated w r t time and location 29 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Module name Tasks Comments awdp _ inversion Inversion Interface to genscat inversion awdp_ambrem Ambiguity Removal Interface to genscat ambrem awdp_icemodel Ice screening Interface to genscat icemodel Table 4 1 AWDP process modules Each module contains code for performing one or more of the specific tasks These tasks are briefly described in table 4 1 A more elaborate description is given in section 4 3 The first module listed awdp_data is a general support module This module is used by the other modules of the process layer for the inclusion of definitions of the data structures and the support routines The second module layer is the genscat layer The genscat module classes i e groups of modules used in the AWDP program are listed in table 4 2 The genscat package is a set of generic modules which can be used to assemble processors as well as pre and post processing tools for different scatterometer instruments available to the user community A short description of the main interface modules is given in section
51. be combined with the ice screening which is done in the GRIB collocation In this case the SST of the GRIB file will be used to assign a WVC as surely water when the SST is above a certain value Switch off ambiguity removal default is switched on 16 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 This option is useful if the selection of the scatterometer wind solution is left to the data assimilation procedure of a Numerical Weather Prediction model In other words the NWP model is fed with a number of solutions and their probability and finds the best value when comparing with other data sources nowrite Do not produce BUFR output default is switched on ignorellflags Ignore the setting of level 1b o related flags in BUFR input If this option is switched on the value of the flags and quality indicators in the beam information including the sigma0 usability and land fraction is neglected cmod lt N gt Choose CMOD version 4 5 55 5n default or 6 With this option the user can choose between GMF version CMOD4 CMODS5 CMODS 5 CMODS 0 5 m s CMOD5n CMODS for neutral winds or CMOD6 The GMF table is generated by the program and written to a binary file named c vv2 dat in the current directory if it does not yet exist Alternatively the user may specify a file name including path in the environment variable LUT_FILENAME_C_VV If SLUT
52. cat support bufr Routine Call Description bufr_open open_BUFR_file Open file bufr_split open_BUFR_file Find position of start of messages in file bufr_read_allsections get BUFR_message Read BufrMessageType from BUFR file bufr_get_section_sizes bufr_swap_allsections get BUFR_message get BUFR_message save BUFR message Optional byte swapping bufr_write_allsections save BUFR message Write BufrMessageType to BUFR file bufr_close close BUFR file bufr_error see appendix B 3 Error handling Table 8 6 Routines in library bufrio 8 5 BUFR table routines BUFR tables are used to define the data descriptors The presence of the proper BUFR tables is checked before calling the reading and writing routines If absent it is tried to create the needed BUFR tables from the text version available in genscat 8 6 Centre specific modules BUFR data descriptors are integers These integers consist of class numbers and numbers for the described parameter itself These numbers are arbitrary To establish self documenting names for the BUFR data descriptors for a Fortran 90 code several centre specific modules are created These modules are listed in table 8 7 Note that these modules are just cosmetic and not essential for the encoding or decoding of the BUFR data They are not used in AWDP Module Description WmoBufrMod WMO standard BUFR data description KnmiBufrMod KNMI BUFR data description EcmwfBufrMod ECMWF BUFR data description
53. cesesssesecuseescceescesesseeseceesecaeeeeedeeseeseeaeeecnseeeenaeeeeeaeeaes 58 6 5 THESPRES GAT SCHEMES i c cc8cses toctet egeeucet eta hecs cevavenes senshh eeadGeses Ti cbtegcoeeeenns Seeusuieettente eetaeeeeeaes ee 58 CHAPTER 7 MODULE ICEMODELMOD u cssscccssssscscssssscsssscccssssccesssccccsssscccessccccessccscssssccsesssseceses 59 7A BACKGROUND orcun seccsstv eee a cose ee a eet dda Pe Ee sen inten e Pee h sees ieee eee 59 7 2 ROUTINES sieren e a E a a E E ni eens oes aie oe 60 7 3 DATA STRUCTURES oain niee get E EE REE he ee ARE AN 60 CHAPTER8 MODULE BUFRMOD eessoseessesesssccssoceessocecsseceseseesscceesseceessecsssoecsscceesseceessecsscoeessoceessee 62 8 1 BACKGROUND orreina i E a a E Ss ees EE ee ee 62 8 2 FROUWDINES 2242002 DAE A E E E NET 62 8 3 DATA STRUCTURES notio e e ok a i e T O oe Re a Reb eee ee eS 64 8 4 TAIBRARIBS EEEE ETO ESEA ES A E E AS 65 8 5 BUFR TABLE ROUTINES oe E E E E E E A E as E eee 66 8 6 CENTRE SPEGIPIC O1 B101 B NEE EE T isle cos T E T 66 CHAPTER9 MODULE GRIBIO_MODULE ccccssscssssssscsssssccsssssscscsssccsssssccsessscccesssscsessssccsessssccesss 67 9 1 BACKGROUND i inei i enii i ie iE EE EEE EE EE AE i Ean 67 9 2 ROUTINES eeen e n a a E e eens ole oe 67 9 3 DATA STRUCTURES vn o raa EE EE EEE aE E EE A ORE R 69 9 4 TSIBRARIES oiea a a a a aa a ihc sterile 70 REFERENCES R EE E RE S E A EE A E T EE T 71 APPENDIX A CALLING TREE FOR AWDP seessececssececssecssccecssocecssecesssecssooeessoceesece
54. cess_flag init cell Initialise process flag structure init_time init cell Initialise time structure init_wind init cell Initialise wind structure print_ambiguity Print ambiguity structure print_beam Print beam structure print_cell Print cell structure print_full_res Print full resolution structure print_icemodel Print ice model structure print_nwp_stress_param Print NWP stress parameters structure print_process_flag Print process flag structure print_time Print time structure print_wind Print wind structure print_wvc_quality Print quality flag structure set_beam_collocation Convert logical beam collocation to integer set_knmi_flag Sets unsets KNMI QC flag depending on other flag settings set_kp_estim_qual Convert logical K estimate quality to integer set_wvc_quality Convert logical WVC quality to integer test_beam test_cell Test validity of beam data test_cell Test validity of cell data test_time test_cell Test validity of time data test_wind test cell Test validity of wind data Table 4 18 Routines in module awdp_data 4 3 2 Module awdp_bufr The module awdp_bufr maps the AWDP data structure on BUFR messages and vice versa A list of the BUFR data descriptors can be found in appendix C Satellite and instrument identifiers are listed in tables 4 19 and 4 20 Note that the first Metop mission is Metop 2 which is also known as Metop A The awdp_bufr module uses the genscat module BufrMod see subsection 4 2 3 for the interface with the BUFR r
55. cription missing Flag not set all bits on qual_sigma0 22 4194304 Not enough good o available for wind retrieval azimuth 21 2097152 Poor azimuth diversity among o kp 20 1048576 Any beam noise content above threshold monflag 19 524288 Product monitoring not used monvalue 18 262144 Product monitoring flag knmi_qc 17 131072 KNMI quality control fails var_qc 16 65536 Variational quality control fails land 15 32768 Some portion of wind vector cell is over land ice 14 16384 Some portion of wind vector cell is over ice inversion 13 8192 Wind inversion not successful large 12 4096 Reported wind speed is greater than 30 m s small 11 2048 Reported wind speed is less than or equal to 3 m s rain_fail 10 1024 Rain flag not calculated rain_detect 9 512 Rain detected no_background 8 256 No meteorological background used redundant 7 128 Data are redundant gmf_distance 6 64 Distance to GMF too large Table 4 16 Wind Vector Cell quality flag bits Fortran Cell process flag Besides a cell quality flag every WVC contains a process flag The process flag checks on aspects that are important for a proper processing but are not available as a check in the cell quality flag The cell process flag is set by the routine test_cell which calls routines test_time test_beam and test_wind Table 4 17 lists the attributes of the process_flag_type The process flag is only available internally in AWDP The routine print_process_flag may be used to
56. d stored with the information of each WVC 3 Inversion The values are compared to the Geophysical Model Function GMF by means of a Maximum Likelihood Estimator MLE The wind vectors that give the best description of the o values the solutions are retained The MLE is also used to assign a probability to each AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 wind vector The normal scheme allows 2 solutions at most but in the Multiple Solution Scheme MSS the maximum number of solutions is 144 4 Quality Control Solutions that lie far away from the GMF are likely to be contaminated by e g sea ice or confused sea state During Quality Control these solutions are identified and flagged 5 Ambiguity Removal This procedure identifies the most probable solution using some form of external information AWDP uses a two dimensional variational scheme 2DVAR as default A cost function is minimized that consists of a background wind field and all solutions with their probability using meteorological balance mass conservation and continuity as constraints 6 Quality Monitoring The last step is to output quality indicators to an ASCII monitoring file and to write the results in a BUFR format output file Figure 2 1 AWDP processing scheme The wind vectors and their probabilities after Quality Control may be fed directly in the Data Assimilation step of a Nu
57. d presence within each WVC is determined using the land sea mask available from the model data The weighted mean value of the land fractions of all model grid points within 80 km of the WVC centre is calculated and if this mean value exceeds a threshold of 0 02 the qual _sigma0 flag in wvc_quality is set The land flag in wvc_quality is set if the calculated land fraction is above Zero NWP forecast wind data are necessary in the ambiguity removal step of the processing Wind 43 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 forecasts with forecast time steps of 3h 6h 36h can be read in The model wind data are linearly interpolated with respect to time and location and put into the model_wind part of each WVC 4 3 6 Module awdp_inversion Module awdp_inversion serves the inversion step in the wind retrieval The inversion step is done cell by cell The actual inversion algorithm is implemented in the genscat modules inversion and post_inversion see subsection 4 2 1 Table 4 26 provides an overview of the routines and their calls in this module Routine Call Description init_inversion invert_wvcs __ Initialisation invert_node invert_wvcs Call to the genscat inversion routines invert_wvcs AWDP Loop over all WVCs and perform inversion Table 4 26 Routines of module awpd_inversion 4 3 7 Module awdp_ambrem Module awdp_ambrem controls the ambi
58. e 34 NWP SAF AWDP User Manual and Reference Guide Doc ID Version Date NWPSAF KN UD 005 23 February 2014 Cell Data The cell type data type is a key data type in the AWDP program because many processing steps are done on a cell by cell basis The attributes are listed in table 4 7 The routine init_cell sets the cell data to missing values Also the flags are set to missing The routine test _cell tests the validity of data This routine sets the cell process flag The routine print_cell may be used to print the cell data Attribute Type Description centre_id integer Identification of originating generating centre sub_centre_id integer Identification of originating generating sub centre software_id_ lb integer Software identification of level 1 processor satellite_id integer Satellite identifier sat_instruments integer Satellite instrument identifier sat_motion real Direction of motion of satellite time time_type Date and time of data acquisition lat real Latitude of WVC lon real Longitude of WVC pixel_size_hor real Distance between WVCs meters orbit_nr integer Orbit number node_nr integer Across track cell number height atmosphere real Height of atmosphere used loss_unit_lenght real Loss per unit length of atmosphere beam_collocation beam_collocation_type Beam collocation flag beam 3 beam_type Beam data full_res full_res_type Averaged full resolution data software_id_sm integ
59. e Guide Date February 2014 may be run on every modern Unix or Linux machine In principle AWDP can also be run on a Windows machine if a Linux environment like the Windows Installer for Ubuntu Wubi is installed 13 Testing AWDP Modules are tested by test programs and test routines Many test routines or test support routines are part of the modules themselves Test programs can be compiled separately For the AWDP program the description of the test programs and the results of the testing are reported in Verhoef et al 2013 1 4 User Manual and Reference Guide This document is intended as the complete reference book for AWDP Chapter 2 is the user manual UM for the AWDP program This chapter provides the basic information for installing compiling and running AWDP Chapter 3 contains the Product Specification PS of the AWDP program Reading the UM and the PS should provide sufficient information to the user who wants to apply the AWDP program as a black box The subsequent chapters are of interest to developers and users who need more specific information on how the processing is done The Top Level Design TLD of the code and the Module Design MD of the AWDP code can be found in Chapter 4 Several modules are very generic for NRT scatterometer data processing Examples are the modules for the BUFR and GRIB handling ambiguity removal and parts of the wind retrieval These generic modules are part of the generic scatterome
60. e collocated with the Wind Vector Cells The next steps are the inversion and the ambiguity removal These steps are performed on the output data The program ends with the post processing step which includes some conversions and the monitoring and the mapping of the output data structure onto BUFR messages of the BUFR output file The different stages in the processing correspond directly to specific modules of the code These modules form the process 28 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 layer see section 4 3 Read input data Read full resolution data Figure 4 1 Baseline of the ASCAT Wind Data Processor 4 1 2 Layered model structure AWDP is a Fortran 90 program consisting of several Fortran 90 modules which are linked after their individual compilation The AWPD program is set up from two layers of software modules The purpose of the layer structure is to divide the code into generic scatterometer processing software and ASCAT specific software Details on the individual modules can be found in sections 4 2 and 4 3 The first layer the process layer consists of modules which serve the main steps of the process Module name Tasks Comments awdp data Definition of data structures awdp_bufr BUFR file handling Interface to genscat support bufr awdp_pfs PFS file handling Interface to genscat support pfs awdp_prepost Sorting of input Duplic
61. e found in the reports de Vries and Stoffelen 2000 de Vries Stoffelen and Beysens 2005 The performance of 2DVAR with meteorological balance constraints was tested and optimized for ERS data It was found to be superior to other schemes 3 5 9 Monitoring For the automatic ingestion of observations into their NWP systems meteorological centres require quality checks on the NRT products For the ASCAT wind product a monitor flag is under development analogous to the one developed for the SeaWinds Wind Product This flag indicates that several measures on the level of corruption of the output BUFR files are above a specified threshold Onset of the flag indicates that the input should be rejected for ingestion by the NWP system Details on the monitor developed can be found in the NWP SAF document de Vries Stoffelen and Beysens 2005 3 6 Details of performance AWD is delivered with two example BUFR input files containing data from 26 April 2007 They are named ascat_20070426_test_250 11_bufr 25km cell spacing and ascat_20070426_test_125 11_bufr 12 5 km cell spacing and contain approximately half an orbit of data Moreover a set of ECMWF GRIB files containing the necessary NWP output is supplied Table 3 2 gives the approximate times needed for processing these files under various options on a personal workstation with a 2 66 GHz Pentium 4 processor under Linux using the GNU g95 Fortran compiler Cell spacing m MSS I
62. e raain etea 10 2 3 INSTALLING AWDP nnen nen oc cc ie E AEE aa E ENEE a ea Ea E ai 10 2 314 Direct ri esand files ice iis weit AE ie BA i es es nhh ae n S 11 2 3 2 Installing the BUFR Tibrary c eccccccecsccssecscesecuseseceseeseesecseesecaecseesecaeeeeceseeseesecaeesecateeecaeeeeeaees 12 2 3 3 Installing the GRIB APLEIibrary eehed niae eiea ee 12 2 35 4 Manual compilation and linking c cceccccccccccceecesessseecueesceseeseeseceeecseescnseeseeseceeecnseeseeaeereerees 13 235 Environment variables cacik E E E EEE E E E 15 2 4 COMMAND LINE OPTIONS ccssssceceessececsseececseceecessaececsaseesecseeeecessaeeecsesaececeaeecsesaeeecsesaeeeeneeeenes 15 2 5 SCRIPTS 9 rea e KE E RI E Er EEEE EEO ROEA E A ARIRE EEE EARE 19 2 6 TEST DATA AND TEST PROGRAMS 2 cssccccssssecesssececesaececseaeececeneeeceesaeeecsesaeeeceeeeesesaeeeceesaeeseneeeenes 19 2 7 DOCUMENTATION roisia ian EREE E AEEA E E E E ORE E R 21 CHAPTER3 AWDP PRODUCT SPECIFICATION cssscccssssscssssscscssssccccssscscssscccsssccssssssceeees 22 3 1 PURPOSE OF PROGRAM AWD ccssccccessseceesssceceesaesecesaseceseseecsesaeseceeaaecesenseecsesaeeeceeaaeesenenaeses 22 3 2 OUTPUT SPECIFICATION n apron oa at E ooidedel ae ven V AEE raed ete ede diane 22 3 3 INPUT SPECIFICATION eent oeir e th fadesbbadesacens chashts cendecbat eesihedsdagese cunsbopereleneh e a aE 23 3 4 SYSTEM REQUIREMENTS iceri i esri iaieiiea E E aeeai ia E ee E scenes 23 3 5 DETAILS OF FUNCTIONA
63. eal Rotation angle cell Integer Store batch cell number row Integer Store batch row number igrid Integer Row index Jgrid Integer Node index lat Real Latitude to determine structure function Wil Real Weight lower left Wir Real Weight lower right Wul Real Weight upper left Wur Real Weight upper right ubg Real Background EW wind component vbg Real Background NS wind component NrAmbiguities Integer Number of ambiguities incr AmbilncrType Ambiguity increments uAnalncr Real Analysis increment vAnalncr Real Analysis increment selection Integer Selection flag QualFlag TwoDvarQualFlagType Quality control flag f Real Cost function at observation gu Real df du gv Real dfidv Table 6 8 The Obs2dvarType data structure 54 AWDP User Manual and Doc ID NWPSAF KN UD 005 Version 2 3 NWP SAF Reference Guide Date February 2014 Attribute Type Description delta Real 2DVAR grid size in position domain delta_p Real 2DVAR grid size in frequency domain delta_q Real 2DVAR grid size in frequency domain NI Integer Dimension of 2DVAR grid Hl Integer N1 2 Kl Integer H1 1 number of nonnegative frequencies N2 Integer Dimension 2 of 2DVAR grid H2 Integer N2 2 K2 Integer H2 1 number of nonnegative frequencies Necontrol Integer Size of control vector Table 6 9 The TDV_Type data structure Routine Call Description TDV Init InitTwodvarModule Initialization of 2DVAR grid and preparations Set_Helmholz
64. ection 9 2 describes the routines in module gribio_module The available data structures are described in section 9 3 The gribio_module uses two libraries from the GRIB software library of ECMWF This is discussed in some more detail in section 9 4 9 2 Routines Table 9 1 provides an overview of the routines in module gribio_module The most important ones are described below Routine Call Description init_GRIB_module AWDP Initialization routine dealloc_all_GRIB_messages AWDP Clear all GRIB info from memory and close GRIB files set_GRIB filelist AWDP Open all necessary GRIB files get from_GRIB filelist AWDP Retrieve GRIB data for a given lat and lon get_colloc_from_GRIB_filelist inquire_GRIB filelist AWDP Inquiry of GRIB file list 67 NWP SAF AWDP User Manual and Reference Guide Doc ID Version Date NWPSAF KN UD 005 T23 February 2014 Routine Call Description get_colloc_from_GRIB_filelist get GRIB_msgnr display_req_GRIB_msg_properties display_GRIB_message_properties open_GRIB file read_GRIB_header_info extract_data_from_GRIB_message get_GRIB_data_values dealloc_GRIB_message get_analyse_dates_and_times check_proximity_to_analyse get _field_from_GRIB_file get_from_GRIB_file add _to GRIB filelist get analyse _dates_and times get_colloc_from_GRIB_filelist AWDP get_field_from_GRIB_file get_from_GRIB file get_from_GRIB filelist inquire_GRIB_filelist ge
65. ed for real time data processing The main application of AWDP is to form the core of an Observation Operator for ASCAT scatterometer data within an operational Numerical Weather Prediction System Program AWDP is also a level 2 data processor It reads data from the EUMETSAT level 1b ASCAT BUFR or PFS product or from the ESA ERS scatterometer BUFR product AWDP applies algorithms for inversion quality control and Ambiguity Removal at various spatial resolutions These methods are mainly developed and published by KNMI The output of AWDP is a BUFR file in ASCAT BUFR format 3 2 Output specification The wind vectors generated by AWDP represent the instantaneous mean surface wind at 10 m anemometer height in a 2D array of Wind Vector Cells WVCs with specified size 25 x 25 km or 12 5 x 12 5 km depending on the cell spacing of the input product These WVCs are part of the ground swath of the instrument In conventional mode the wind output for every WVC consists of up to 4 ambiguities wind vector alternatives with varying probabilities The selected wind vector is indicated by a selection index For every WVC additional parameters are stored These are e g latitude longitude time information orbit and node numbers background wind vector cell quality flag and information on the scatterometer beams including o and K data The output file is structured according to the same conventions as the ASCAT level 1b input also if ERS d
66. ed the analysis Second the selected wind vector field the result of the 2DVAR scheme consists of the wind vector solutions that are closest to the analysis wind vector For details on the KNMI 2DVAR scheme formulation the reader is referred to Vogelzang 2007 Information on 2DVAR can also be found in Stoffelen de Haan Quilfen and Schyberg 2000 de Vries Stoffelen and Beysens 2005 de Vries and Stoffelen 2000 The calculation of the cost function and its gradient is rather complex matter The reader who is only interested in how the 2DVAR scheme is assembled into the genscat module class ambrem is referred to subsection 6 4 2 Readers interested in the details of the cost function calculations and the minimization should also read the subsequent subsections Subsection 6 4 3 forms an introduction to the cost function It is recommended to first read this section because it provides necessary background information to understand the code Subsection 6 4 7 on the actual minimization and subsection 6 4 8 on Fast Fourier Transforms are in fact independent of the cost function itself The reader might skip these subsections 6 4 2 Data structure interface and initialisation The main module of the 2DVAR scheme is TwoDvar Within the genscat ambiguity removal module class the interface with the 2DVAR scheme is set by module Ambrem2DVAR Table 6 6 lists its routines that serve the interface with TwoDvar 53 AWDP User Manual and Doc ID N
67. ed to determine if a WVC contains suitable backscatter data for wind inversion Several options for the processing can be invoked szffl lt file gt stressparam noinv icemodel lt IM gt noamb Read a list of full resolution PFS file names in the file named file The files in the list are read and the full resolution PFS data SZF are used to replace the 25 km 12 5 km beam data This option is intended to produce a coastal wind product The beam data o values incidence and azimuth angles which are read from the BUFR or PFS level 1b input file are replaced by average values of the data from the full resolution file which are located within a certain radius typically 10 to 20 kilometers from the WVC location See section 3 5 3 for more information Get stress related parameters derived from GRIB files This option is intended for research activities More information can be found in the Fortran code of AWDP Switch off inversion default is switched on Choose ice screening method to be used 0 default 1 or 2 The value 0 results in no ice screening except when a GRIB file containing sea surface temperature is read The value 1 invokes a simple non Bayesian ice model which does not keep history of the water or ice state of each location Value 2 invokes the Bayesian ice model which keeps the history of each location and uses this history to determine the sea or ice state of a WVC The ice screening can
68. ee table 8 4 The actual data for input or output in a BUFR message should be an instance of the BufrDataType data type Some meta information on the BUFR file is contained in the self explaining bufr_file_attr_data data type see table 8 5 Attribute Type Description nr_of BUFR_mesasges integer Number of BUFR messages bufr_filename character BUFR file bufr_fileunit integer Fortran unit of BUFR file file_size integer Size of BUFR file file_open logical Open status of BUFR file writemode logical Reading or writing mode of BUFR file is_cray_blocked integer Cray system blocked list_of BUFR_startpointers integer Pointers to BUFR messages message_is_valid logical Validity of BUFR messages Table 8 5 Attributes of the bufr_file_attr_data data type for BUFR files 8 4 Libraries Module BufrMod uses two libraries the BUFR software library of ECMWF and bufrio a small 65 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and es D Reference Guide Date February 2014 library in C for file handling at the lowest level The BUFR software library of ECMWF is used as a basis to encode and decode BUFR data This software library is explained in Dragosavac 1994 Library bufrio contains routines for BUFR file handling at the lowest level Since this is quite hard to achieve in Fortran these routines are coded in C The routines of bufrio are listed in table 8 6 The source file oufrio c is located in subdirectory gens
69. emoval and BUFR and GRIB file handling These routines are discussed in more detail in Chapter 5 to Chapter 9 co EUMETSAT KNMI Figure 2 2 AWDP wind field retrieved for 15 April 2007 approximately 13 h UTC at 25 km cell spacing near Newfoundland overlaid on a GOES IR satellite image The yellow dots are rejected WVCs The blue and violet arrows are a 6 hours forecast from the KNMI HIRLAM model DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Tea aa Reference Guide Date February 2014 2 2 Modes of using AWDP There are several modes to assimilate the ASCAT data in NWP models using AWDP Anyway the first thing to assure oneself of is the absence of biases by making scatter plots between ASCAT and NWP model first guess for at least wind speed but wind direction and wind components would also be of interest to guarantee consistency The operational ASCAT wind product available as a deliverable from the EUMETSAT OSI SAF project could be the starting point for NWP assimilation 1 The unique solution at every WVC may be assimilated as if it were buoy data This is the fastest way and one exploits the data to a large extent For a small advantage AWDP could be installed to provide 2DVAR solutions based on the local first guess 2 The AWDP software may be used to modify the 3DVAR or 4DVAR data assimilation system to work with the ambiguous wind solutions and their probabilities at every WVC This represents some i
70. enscat make system to construct the BUFR tables required by AWDP but it can also be used to test the genscat BUFR module The program is used as follows test_modules BUFRinput where BUFRinput is the BUFR input file If omitted the program uses as default input the file testreading bufr in directory genscat support bufr The output is written to a BUFR file named testwriting bufr The directory also contains a shell script named run_test_modules that sets the environment variables required and executes the program Further information can be found in the comment lines of the source code of test_modules Directory genscat support grib contains test programs named test_read_GRIB1 test_read_GRIB2 and test_read_GRIB3 The programs can be run from the command line and read in the GRIB file testfile grib in directory genscat support grib Some properties of this file are written to ASCII output files Note that the environment variable SGRIB_ DEFINITION PATH needs to be set to directory genscat support grib definitions Subdirectories Compiler_Features convert ErrorHandler singletonfft file BFGS num sort and datetime of genscat support contain test programs for the module in that subdirectory The test programs write their result to the standard output In some cases a copy of the output is contained in the out put files for comparison Table 2 6 gives a
71. enssuatestevs 44 4 3 9 Mod le awd ea ra aa A a A a E a a ar E 45 CHAPTER 5 INVERSION MODULE eesseoeesseoesssecssccecsseceessecsssoecssoceesseceessecsscseesscceesseceessecsssseessocseesse 46 5 1 BACKGROUND srin e ac E EE nee nee ae 46 5 2 ROUTINES cenu 65 ra e ees 2s aah a in weeded ae ae EE de ET nes eos 47 5 3 ANTENNAS DIRECTION esris aeree tn a Qhctedetatece ckutlel waded eakiehathcacess desl vhahdedR edhsvtedkGatese ket 48 CHAPTER 6 AMBIGUITY REMOVAL MODULE wuu ccssccccsssssssssscccssssccccssscccesssccccsssccscsssseceses 49 6 1 AMBIGUITY REMOVAL narren ian ann i e e i E A E 49 6 2 MODULE AMBREM sni nen a a E EE ik tienes obese o ee AEE DTi 49 6 3 MODULE BATCHM OD ne aitai ia E Ea EE E E a E E i aTe 50 6 4 THE KNMI2D VAR SCHEME vorera E EEE EN E E EEEE 53 6 4 1 TUT OGUCHION PERENE EAE OA ESAO AT IE AE E AE IES OE EEA AEE AEE 53 6 4 2 Data structure interface and initialisation ccccccccececcceceeeceeeet cet ceteeeeseeeseeeseseeuseeneeeeaes 53 6 4 3 Reformulation and trans fOrmation ccccccccccccecesscesesieesecssseecnecseeeecuseeseeseeseeecieeeecnssesenseeseeaeeaes 56 64 4 Module COStFUNCHON sorier eere i aae a a i E A E E 56 6 4 3 Adjoint method osese tiriseee ereas aaa ae arena iaeiiio iele slri iaie a Tie eiia 56 64 6 Slr cture Functions enerne a ear kh RS ea a aa aa wt teak aa aaiae 57 647a MANN IZATION sce HR e an ah aia is e aa s e Mesa ee te Mi sib 57 6 4 8 SingletonFFT Module ccccceccscesccesess
72. er Soil moisture information database_id integer Soil moisture information surface_sm real Soil moisture information surface_sm_err real Soil moisture information sigma0_40 real Soil moisture information sigma0_40_err real Soil moisture information slope_40 real Soil moisture information slope_40_err real Soil moisture information sm_sensitivity real Soil moisture information dry_backscatter real Soil moisture information wet_backscatter real Soil moisture information mean_surface_sm real Soil moisture information rain_fall_detect real Soil moisture information sm_corr_flag integer Soil moisture information sm_proc_flag integer Soil moisture information sm_quality real Soil moisture information snow_cov_frac real Soil moisture information froz_land_frac real Soil moisture information inund_wet_frac real Soil moisture information topo_complexity real Soil moisture information software_id_wind integer Software identification of level 2 wind processor generating app integer Generating application of model information model_wind wind_type Model wind used for Ambiguity Removal ice_prob real Probability of ice ice_age real Ice age A parameter wvc_quality wvc_quality_type WVC quality flag num_ambigs integer Number of ambiguities present in WVC selection integer Index of selected wind vector skill real Parameter used for PreScat Ambiguity Removal 35 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version
73. et_szo_node get_time get_ushort get_uint ymd2julian julian2ymd get_ushort1 get_ushort get_int1 get_int get_uint1 get_uint get_int3 get_int get_ushort3 get_ushort get_short3 get_short get_uchar3 get_szr_node get_smo_node get_smr_node get_szf_grid_node ymd2julian calc_asc Figure B5 3 Calling tree for PFS file handling routine get_pfs_ascat_node The calling tree for get_szr_node get_smo_node get_smr_node and get _szf_grid node is identical to to the one of get_szo_node 95 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 gt get_pfs_ascat_fres_node get_time get_ushort get_uint ymd2julian julian2ymd get_int1 get_int get_ushort1 get_uint1 get_uint get_uchar1 ymd2julian calc_asc Figure B5 4 Calling tree for PFS file handling routine get_pfs_ascat_szf_node 96 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and es D Reference Guide Date February 2014 Appendix B6 Calling tree for ice model routines The figures in this appendix show the calling tree for the ice model routines in genscat All routines are part of genscat as indicated by the black boxes An arrow before a routine name indicates that this part of the calling tree is a continuation of a branch in a previous figure The same arrow after a routine name indicates that this branch will be continued in a following figure Expandintege
74. evious ice map update xy IcePixel nPixels nLines Pointer to the ice map contents Table 7 3 Attributes for the IceMapType data type 61 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Teea aa Reference Guide Date February 2014 Chapter 8 Module BufrMod Module BufrMod is part of the genscat support modules The current version is a Fortran 90 wrapper around the ECMWF BUFR library see http www ecmwf int The goal of this support module is to provide a comprehensive interface to BUFR data for every Fortran 90 program using it In particular BufrMod provides all the BUFR functionality required for the scatterometer processor based on genscat Special attention has been paid to testing and error handling 8 1 Background The acronym BUFR stands for Binary Universal Form for the Representation of data BUFR is maintained by the World Meteorological Organization WMO and other meteorological centres In brief the WMO FM 94 BUFR definition is a binary code designed to represent employing a continuous binary stream any meteorological data It is a self defining table driven and very flexible data representation system It is beyond the scope of this document to describe BUFR in detail Complete descriptions are distributed via the websites of WMO http www wmo int and of the European Centre for Medium range Weather Forecasts ECMWF http www ecmwf int Module BufrMod is in fact an interface On the one
75. f an icemap latestIceMapN rst for the North Pole and latestIceMapS rst for the South Pole With the next call of awdp these restart files are read in again Environment variable SRESTARTDIR contains the directory for the ice model restart files Optionally sea surface temperature SST data from GRIB files can be used to further improve the 59 Doc ID Version Date NWPSAF KN UD 005 2 3 February 2014 AWDP User Manual and Reference Guide NWP SAF quality of the ice algorithm the use_sst logical must be turned on Processing llb input with the use of NWP data and SST data can be done with the following command line options lt bufr file gt icemodel 2 mon awdp f lt gribfilelist gt handleall nwpf Reprocessing of level 2 input with only running the ice model on top of it can be done with the following command line options icemodel 2 noinv noamb mon handleall awdp f lt bufr file gt The SSM I grids are widely used for representation of ice related parameters A good description as well as some software routines can be found on the website of the National Snow and Ice Data Centre NSIDC http www nsidc org data docs daac ae_si25_25km tb and _sea_ice gd html A more detailed description of the Bayesian statistics method and ice model is given in Belmonte et al 2012 7 2 Routines Table 7 1 provides an overview of the routines in module iceModelMod Ro
76. f org 2 1 Why using the AWDP program Scatterometers provide valuable observational data over the world s oceans Therefore successful assimilation of scatterometer data in numerical weather prediction systems generally improves weather forecasts The AWDP program has been developed to fully exploit scatterometer data It is meant to form the key component of the observation operator for surface winds in data assimilation systems The general scheme of AWDP and any other wind scatterometer data processor is given in figure 2 1 The input of the AWDP program is the EUMETSAT ASCAT level 1b BUFR or PFS wind product combined with ASCAT level 1 full resolution data in PFS in the case of coastal wind product processing or the ESA ERS level 2 BUFR wind product Besides this GRIB input containing land sea mask sea surface temperature or soil temperature on level 0 and first guess winds over the globe is necessary The AWDP processing chain contains several steps see figure 2 1 1 Pre processing The input file is decoded and the radar backscatter o values are written in the data structures of AWDP In the case of coastal product processing the full resolution SZF backscatter data are read and averaged Some quality control on the input data is done 2 Collocation with NWP data The GRIB edition 1 or 2 files containing NWP data are read and the values for land fraction sea surface temperature and first guess winds are interpolated an
77. for the WVC a second naive Ambiguity Removal scheme is at hand the Background Closest BC scheme The selected wind vector is just the minimizer of the distance e g in the least squares sense to the background wind vector This scheme may produce far more realistic wind vector fields than the first rank selection since the background surface wind field is meteorologically consistent However background surface winds have their own uncertainty Therefore sophisticated schemes for Ambiguity Removal take both the likelihood of the ambiguities and the uncertainty of the background surface wind into account Examples are the KNMI Two Dimensional Variational 2DVAR scheme and the PreScat scheme The implementation of these schemes is described in sections 6 4 and 6 5 6 2 Module ambrem Module Ambrem is the interface module between the various ambiguity removal methods and the different scatterometer data processors Table 6 1 provides an overview of the different routines 49 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 and their calls A dummy method and the first rank selection method are implemented as part of ambrem More elaborate Ambiguity Removal methods have an interface module see table 6 2 Figure 6 1 shows schematically the interdependence of the various modules for Ambiguity Removal Routine Call Description InitAmbremModule AWDP Initia
78. fore and two after are provided I SSY 2 3 the software will still work and use all three forecasts Checking and Printing The integer parameter GribVerbosity controls the extent of the log statements while processing the GRIB data As said before the underlying encoding and decoding routines originate from the ECMWF GRIB library Appendix B4 shows the calling trees of the routines in module gribio_module that are used in AWDP 9 3 Data structures Some meta information on the GRIB file is contained in the self explaining grib file_attr data data type see table 9 2 The decoded GRIB messages in the GRIB files with their meta information are contained in the grib_message_ data see table 9 3 Attribute Type Description nr_of_GRIB_messages integer Number of messages in this file grib_filename character array Name of GRIB file grib_fileunit integer Unit number in file table file_size integer Size of GRIB file in bytes file_open logical Status flag list_of GRIB_message_ids integer array Message ids assigned by GRIB API list_of GRIB_level integer array Key to information in messages list_of GRIB_level_type integer array Key to information in messages list_of GRIB_date integer array Key to information in messages list_of GRIB_hour integer array Key to information in messages list_of GRIB_analyse integer array Key to information in messages list_of GRIB_derived_date integer array Key to information in messages list
79. guity removal step of the AWDP program The actual ambiguity removal schemes are implemented in the genscat module ambrem see section 4 2 2 The default method is the KNMI 2DVAR scheme Table 4 27 lists the tasks of the individual routines Routine Call Description fill_batch remove_ambiguities Fill a batch with observations remove_ambiguities AWDP Main routine of ambiguity removal select_wind remove_ambiguities Final wind selection Table 4 27 Routines of module awpd_ambrem The ambiguity removal scheme works on a so called batch The batch is defined in the fill_ batch routine For the AWDP program a batch is just a set of rows The size of the batch is determined by the resolution of the structure functions and the number of FFT The genscat routine remove_ambiguities performs the actual ambiguity removal Finally select wind passes the selection to the output WVCs 4 3 8 Module awdp_icemodel Module awdp_icemodel performs the ice screening of the wind product The ice screening works on the principle that WVCs over water yield wind solutions which are close to the GMF cone If a WVC is over ice the o triplets from fore mid and aft beam will be close to the so called ice line Hence there is a possibility to discriminate between water wind and ice WVCs The implementation of this principle is described in more detail in Belmonte et al 2012 The ice screening is done directly after the ambiguity removal step
80. hand it contains temporary definitions to set the arguments of the ECMWF library functions On the other hand it provides self explaining routines to be incorporated in the wider Fortran 90 program Section 8 2 describes the routines in module BufrMod The public available data structures are described in section 8 3 BufrMod uses two libraries the BUFR software library of ECMWF and bufrio a small library in C for file handling at the lowest level These libraries are discussed in some more detail in section 8 4 8 2 Routines Table 8 1 provides an overview of the routines in module BufrMod The most important ones are described below Routine Call Description InitAndSetNrOfSubsets AWDP Initialization routine set BUFR _fileattributes AWDP Initialization routine open_BUFR_file AWDP Opens a BUFR file get BUFR_nr_of messages AWDP Inquiry of BUFR file get BUFR_message AWDP Reads instance of BufrDataType from file get expected BUFR _msg size get BUFR message Inquiry of BUFR file ExpandBufr Message get BUFR_message Convert from BufrMessageType to BufrSectionsType 62 Doc ID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Version 23 Reference Guide Date February 2014 Routine Call Description PrintBufrErrorCode ExpandBufrMessage EncodeBufrData CheckBufrTables ExpandBufrMessage Data check get file size CheckBufrTables Determine size of BUFR file get bufrfile_size_c get file size Support routine in C encode _tab
81. he KNMI inversion approach can be found in Chapter 5 3 5 7 Ice screening A Bayesian sea ice detection algorithm was developed for ASCAT Belmonte et al 2012 and this algorithm is implemented in AWDP It is based on the probabilistic distances to ocean and sea ice geophysical model functions When a combination of backscatter measurements is close to the wind GMF the probability that the WVC is covered with water is high On the other hand when the measurement is close to the sea ice GMF the probability that the WVC contains ice is high Each satellite overpass over the poles will yield new measurements which contribute to an ice map containing the ice probabilities 25 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and PR ae Reference Guide Date _ February 2014 3 5 8 Ambiguity Removal The Ambiguity Removal AR step of the wind retrieval is the selection of the most probable surface wind vector among the available wind vector solutions the so called ambiguities Various methods have been developed for AR More information on Ambiguity Removal is given in Chapter 6 The default method implemented in AWDP is the KNMI 2DVAR AR scheme A description of its implementation can be found in section 6 4 The Multiple Solution Scheme MSS offers the possibility to postpone AR to the NWP step in order to treat all information from models and measurements in the same manner Further details on the algorithms and their validation can b
82. heck the validity of the data and to check the data quality In the AWDP program two flags are set for every WVC see table 4 3 The flags themselves do not address a single aspect of the data but the flags are composed of several bits each addressing a specific aspect of the data A bit is set to 0 1 in case the data is valid not valid with respect to the corresponding aspect In order to enhance the readability of the code each flag is translated to a data type consisting of only booleans false valid true invalid On input and output these data types are converted to integer values by set and get routines Flag Tasks Description wvc_quality Quality checking In BUFR output process_flag Range checking Not in BUFR output Table 4 3 Flags for every WVC attributes of cell_type Apart from the flags on WVC level also the beams contain quality indicators Most of them are implemented as real values ranging from 0 to 1 where 0 stands for good quality and 1 for degraded quality See section 4 3 1 for more information on this 4 1 5 Verbosity Every routine in a module may produce some data and statements for the log of the processor To 31 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 control the size the log several modules contain parameters for the level of verbosity The verbosity of the AWDP program may be controlled by the verbosity command line op
83. ied with the nwpf1 command line option see section 2 4 3 5 4 WVC triplet completion and row merging AWD P sorts the WVC rows in the input file by their acquisition date and time and merges WVC information if duplicate rows occur The duplicate information is considered and the output will contain as much useful information as is available in the input WVCs This is especially useful if direct readout data from different ground stations is processed Sometimes a WVC from one 24 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and PR ae Reference Guide Date February 2014 ground station contains only fore beam information whereas the corresponding WVC from a second ground station contains only the mid and aft beam information AWDP will combine the information and it will process and write one WVC containing all three beams 3 5 5 Quality control The quality of every WVC is controlled Before processing the beam data checks are done on the completeness and usability of the o data After the wind inversion step the distance of the first rank wind solutions to the GMF is considered If this value is too large the wind solutions are flagged The values are also considered If one of the three beam K values is above a threshold which is wind speed dependent the wind information is flagged Stoffelen 1998 3 5 6 Inversion In the inversion step of wind retrieval the radar backscatter observations in terms of the Norma
84. ile should either have the ASCAT or the ERS format The PFS file should contain 25 or 12 5 km level 1b data not full resolution level 1b data 15 NWP SAF AWDP User Manual and Doc ID NWPSAF KN UD 005 Version 2 3 Reference Guide Date February 2014 nwpfl lt file gt Example awdp f ascat_20070426_test_250 11_bufr will process this file The results will be written to a new BUFR file see below in this section for the output file naming convention It is possible to concatenate multiple BUFR input files into one using the Unix cat command but PFS files must be processed one by one Read a list of GRIB file names in the file named file The files in the list are read and the GRIB edition 1 or 2 data are used in the wind processing The most convenient way to construct a file list is to use the Unix command 1s 1 GRIB file pattern gt file Ifno GRIB data are used only the land masking which is present in the level 1b beam information will be used No ice screening will be performed unless the icemodel option is used Ambiguity removal will be performed only if model winds are already present in the input BUFR file i e in case of reprocessing of a level 2 file or if the armeth 1strank option is used i e selection of the 1 rank wind solution If level 2 data are reprocessed and no NWP data are read the qual_sigma0 flag which was set in the initial processing is evaluated and it will be us
85. imum GetSortIndex SortWithindex calc_sign_MLE calc_sigma0 fill_wind_quality_code Figure B1 1 Calling tree for inversion routine invert_one_wvc find _minimum_cone_dist calc_cone_distance calc_sigma0 gt get_parabolic_minimum Figure B1 2 Calling tree for inversion routine find_minimum_cone_dist 84 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and ee ae Reference Guide Date February 2014 gt calc_sigma0 read_LUT get_lun free_lun create _LUT_C_VV get_lun calc_sigma0_cmod4 Get_Br_from_Look_Up_Table f1 calc_sigma0_cmod5 _5 _n free_lun test_for_identical_LUTs my_exit INTERPOLATE Figure B1 3 Calling tree for inversion routine calc_sigma0 Routine INTERPOLATE is an interface that can have the values interpolate1d interpolate2d interpolate2dv or interpolate3d There are several equivalent routines to calculate the CMOD backscatter like calc_sigma0_cmod5 calc_sigmaO_cmod5_5 calc_sigma0_cmod5_n normalize_conedist_prescat_mode check_ers_ascat_inversion_data get_ers_noise_estimate Figure B1 4 Calling tree for inversion routine normalize_conedist_prescat_mode gt normalise_conedist_ers_ascat check_ers_ascat_inversion_data calc_kp_ers_ascat calc_geoph_noise_ers_ascat Figure B1 5 Calling tree for inversion routine normalize_conedist_ers_ascat check_wind_solutions_ers_ascat remove_one_so
86. input data apart If preprocess finds a double row it merges the two rows into one row In that case the number of input rows will be reduced Once the input rows are sorted and merged an output row structure is allocated ant the input data are copied into the output rows The routine pre_inversion_qc which is called by preprocess performs land flagging and checks the setting of flags in the level 1b beam information If the input data is of inferior quality the qual_sigmaO flag in the wvc_quality is set which prevents further processing of this WVC Also the land fractions present in the beam information in the level 1b product are considered if any land fraction in the fore mid or aft beam exceeds 0 02 the gual_sigma0 flag in wvc_quality is set as well The land flag in wvc_quality is set whenever any level 1b land fraction is above zero The next step is the calibration of the o s in calibrate_s0 Calibration coefficients for each level 1 processing version and instrument ASCAT on Metop A or Metop B have been obtained using the so called NWP Ocean Calibration NOC Note that the calibration is done again in the reverse order after the post processing in order to write the o s to output as plain copies of the input o s More information about the calibration can be found in Verspeek et al 2012 The monitoring which is performed as part of the post processing calculates some statistics from the wind product and writes
87. irections rms_diff u RMS over N5 difference between observed and model wind u components rms_diff v RMS over N5 difference between observed and model wind v components rms_diff vec_len RMS over N5 vector length between observed and model winds ambiguity Fraction of N5 where the chosen solution is not the one closest to the model wind Table 4 24 Parameters in monitoring output 4 3 5 Module awdp_grib The module awdp_grib reads in ECMWF GRIB files and collocates the model data with the scatterometer measurements The awdp_grib module uses the genscat module gribio_module see subsection 4 2 5 for the interface with the GRIB routine library Table 4 25 provides an overview of the routines and their calls in this module The genscat support routines uv_to_speed and uv_to dir are used to convert NWP wind components into wind speed and direction Routine Call Description get grib data AWDP Get land mask ice mask and background winds using GRIB data init_grib_processing get grib data Initialise module Table 4 25 Routines in module awdp_grib NWP model sea surface temperature and land sea mask data are used to provide information about possible ice or land presence in the WVCs WVCs with a sea surface temperature below 272 16 K 1 0 C are assumed to be covered with ice and the ice and qual_sigma0 flags in wvc_quality are set Note that this step is omitted if the Bayesian ice screening is used see section 4 3 7 Lan
88. itoring results are written in an ASCH file with the name monitoring_report txt By default no monitoring file is produced Set the verbosity level to L default is 0 If the verbosity level is 1 or smaller no output is written to the standard output except error messages If the verbosity level equals 0 only some top level processing information is written to output If the verbosity level is 1 or greater also additional information is given The normal mode of operation of AWDP is wind processing i e a BUFR or PFS file is read and the various processing steps are performed Note that by default AWDP does not recalculate data that are already present in the input For example if a WVC already contains model winds then the GRIB collocation will not be done for this WVC if a WVC already contains wind solutions then the wind inversion will not be performed This behaviour is desired when near real time processing is performed and a mixture of level 1b and level 2 files is fed into AWDP If one wants to perform reprocessing of level 2 files the behaviour of AWDP can be changed by the command line options e g the handleall1 option Besides the wind processing some other modes of operation are available If one of the modes is invoked AWDP internally sets some of the options in order to obtain the desired result Note that these modes are always used in combination with the f lt input file gt option mononly
89. l gt copy_cell test_cell gt pre_inversion_qc Figure A 4 Calling tree for routine preprocess first level 75 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 gt read_full_res_data GetElapsedSystemTime init_grib_processing init_GRIB_module set_GRIB_filelist gt inquire_GRIB_filelist gt get_lun open_pfs_ascat_file read_pfs_ascat_data_record get_pfs_ascat_fres_node get_distance get_from_GRIB_filelist gt test_cell gt close_pfs_ascat_file free_lun init_l2_wind gt get_wvc_quality Figure A 5 Calling tree for routine read_full_res_data first level gt get_grib_data GetElapsedSystemTime init_grib_processing init_GRIB_module set_GRIB_filelist gt inquire_GRIB_filelist gt get_from_GRIB_filelist gt get_colloc_from_GRIB_filelist gt test_cell gt dealloc_all_GRIB_messages Figure A 6 Calling tree for routine get_grib_data first level 76 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 gt invert_wvcs GetElapsedSystemTime init_inversion init_inv_settings_to_default get_inv_settings set_inv_settings init_inv_input invert_one_wvc gt normalise_conedist_prescat_mode normalise_conedist_ers_ascat check_wind_solutio
90. le_b CheckBufrTables encode _table_d CheckBufrTables FillBufrSecData ExpandBufrMessage Convert from BufrSectionsType to BufrDataType close BUFR file AWDP Closes a BUFR file BufrReal2Int AWDP Type conversion BufrInt2Real AWDP Type conversion save _BUFR_message AWDP Saves instance of BufrDataType to file EncodeBufrData save BUFR message Convert from BufrSectionsType to BufrMessageType CheckBufrData EncodeBufrData Data check FillBufrData EncodeBufrData Convert from BufrDataType to BufrSectionsType bufr_msg_is_ valid not used set_bufr_msg_to_invalid not used PrintBufrData not used GetPosBufrData not used GetRealBufrData not used GetIntBufrData not used GetRealBufrDataArr not used GetIntBufrDataArr not used GetRealAllBufrDataArr not used CloseBufrHelpers not used missing real not used missing int not used int2real not used do_range_check_int not used do_range_check_real not used AddRealDataToBufrMsg not used AddintDataToBufrMsg not used PrintBufrModErrorCode not used GetFreeUnit encode_table_b encode table d Get free file unit Table 8 1 Routines of module BufrMod Reading decoding Routine get BUFR _message reads a single BUFR message from the BUFR file and creates an instance of BufrDataType Writing encoding Routine save BUFR_message saves a single BUFR message to the BUFR file The data should be provided as an instance of BufrDataType Checking and Printing The integer parameter BufrVerbosity controls the e
91. lization of module Ambrem InitAmbremMethod AWDP Initialization of specified AR scheme DoAmbrem AWDP Execution of specified AR scheme Ambrem1stRank DoAmbrem First rank selection method DoDummyMeth DoAmbrem Dummy AR scheme for testing SetDummyMeth DoAmbrem Batch definition of dummy method InitDummyMeth DoAmbrem Initialization of dummy method InitDummyBatch not used ExitAmbremMethod AWDP Deallocation of memory Table 6 1 Routines of module Ambrem Routine Description Documentation Ambrem2DVAR Interface to KNMI 2DVAR method Section 6 4 AmbremBGClosest Interface to Background Closest method Section 6 1 AmbremPrescat Interface to Prescat method Section 6 5 Table 6 2 Interface modules for different Ambiguity Removal schemes 6 3 Module BatchMod After the wind retrieval step the Ambiguity Removal step is performed on selections of the available data In general these selections are just a compact part of the swath or a compact part of the world ocean The batch module BatchMod facilitates these selections of data In fact a batch data structure is introduced to create an interface between the swath related data and the data structures of the different AR methods Consequently the attributes of the batch data structures are a mixture of swath items and AR scheme items Figure 6 2 gives a schematic overview of the batch data structure Descriptions of the attributes of the individual batch data components are given in table 6 3 50 DocID
92. lized Radar Cross Sections as are converted into a set of ambiguous wind vector solutions In fact a Geophysical Model Function GMF is used to map a wind vector specified in term of wind speed and wind direction to a o value The GMF depends not only on wind speed and wind direction but also on the measurement geometry relative azimuth and incidence angle and beam parameters frequency and polarization Currently the CMOD5 GMF which was developed for ERS is in use see Hersbach Stoffelen and de Haan 2007 but improvements are under study The AWDP program also includes the Multiple Solution Scheme MSS In MSS mode a large number of wind vector solutions is produced typically 144 The wind vector solutions are ranked according to their probability based on the MLE and constitute the full wind vector probability density function Subsequently the 2DVAR Ambiguity Removal method see e g section 3 5 8 is applied with a much larger set of wind vector solutions The output BUFR format can accommodate any number of wind solutions due to the use of the so called delayed descriptor replication Details on the KNMI inversion approach can be found in Portabella 2002 For SeaWinds MSS compares better to an independent NWP model reference and buoys than conventional two or four solution schemes Portabella and Stoffelen 2004 Vogelzang et al 2008 but for ERS and ASCAT this needs to be investigated further Technical information on t
93. lution calc_dist_to_cone_center calc_sigma0 gt Figure B1 6 Calling tree for inversion routine check_wind_solutions_ers_ascat 85 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and es D Reference Guide Date February 2014 Appendix B2 Calling tree for AR routines The figures in this appendix show the calling tree for the Ambiguity Removal routines in genscat All routines are part of genscat as indicated by the black boxes An arrow before a routine name indicates that this part of the calling tree is a continuation of a branch in a previous figure The same arrow after a routine name indicates that this branch will be continued in a following figure gt InitTwodvarModule TDV_Init Set_HelmholzCoefficients Figure B2 1 Calling tree for AR routine nitTwodvarModule 86 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 gt DoAmbrem TestBatch TestBatchRow TestBatchCell AmbRemistRank DoAmbremBGclosestOnBatch uv_to_dir DoAmbremPreScatOnBatch DoAmbremBGclosestOnBatch uv_to_dir Do2DVARonBatch BatchInput2DVAR TestBatchCell InitObs2DVAR gt Set_WVC_Orientations rotuv PrintObs2DVAR Do2DVAR gt BatchOutput2DVAR rotuv InitObs2DVAR gt DeallocObs2DVAR DoDummyMeth Figure B2 2 Calling tree for AR routine DoAmbrem gt InitObs2dvar InitOneObs2dvar TestObs2dvar set2DVARQual
94. ly in capitals belong to the ECMWF BUFR library Other routines in grey boxes belong to the bufrio library in C An arrow before a routine name indicates that this part of the calling tree is a continuation of a branch in a previous figure The same arrow after a routine name indicates that this branch will be continued in a following figure open_BUFR_file bufr_error bufr_split Figure B3 1 Calling tree for BUFR file handling routine open _BUFR_file gt close_BUFR_file bufr_close bufr_error Figure B3 2 Calling tree for BUFR handling routine close_BUFR_file 90 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 get BUFR_message get_expected_BUFR_msg_size bufr_read_allsections bufr_error bufr_get_section_sizes bufr_swap_allsections ExpandBufrMessage PrintBufrErrorCode CheckBufrTables get_file_size encode_table_b 2100010 SM t 1e me BUFREX FillBufrSecData BUSEL Figure B3 3 Calling tree for BUFR handling routine get BUFR_message save_BUFR_message EncodeBufrData CheckBufrData FillBufrData PrintBufrErrorCode Figure B3 4 Calling tree for BUFR file handling routine save BUFR file 91 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Appendix B4 Calling tree for GRIB routines The figures in this appe
95. merical Weather Prediction model Step 1 2 and 6 of the processing chain are rather trivial the real work is done in steps 3 4 and 5 Note that an undesirable dependency arises if the output wind field is assimilated into a numerical weather prediction NWP model in the 2DVAR Ambiguity Removal step 1 a background wind field is used and ii meteorological balance constraints causing spatially correlated error Therefore it is recommended to feed the wind solutions and their probabilities directly into the NWP data assimilation step after Quality Control as indicated in figure 2 1 If this is done the Ambiguity Removal step can be skipped and consequently no forecast winds are necessary in the NWP input No impact tests have been performed to date by assimilating AWDP outputs after ambiguity removal As further detailed in Chapter 3 AWDP profits from developments in DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Verion oe Reference Guide Date February 2014 e Inversion and output of the full probability density function of the vector wind Multiple Solution Scheme MSS e Quality Control QC e Meteorologically balanced Ambiguity Removal 2DVAR e Quality monitoring e Capability to process ASCAT data on both 25 km and 12 5 km cell spacing A complete specification of the AWDP program can be found in the Product Specification in Chapter 3 The program is based on generic genscat routines for inversion ambiguity r
96. mply enter make The Makefile refers to each subdirectory of genscat invoking execution of the local Makefile and in cases where a subdirectory contains code as well as a subdirectory containing code Makefile_thisdir The Makefiles need supplementary information from the files Objects txt which are present in each directory containing code The settings for the compilers are located in file Makeoptions in directory genscat This file is generated by the Bourne shell script Set_Makeoptions which is called automatically by the genscat make system The local Makefile in subdirectory genscat support bufr calls the script make bufr 1lib for compilation of the BUFR library see 2 3 2 It also contains the Fortran program test_modules that generates the binary BUFR tables B and D from the ASCII tables already present and is executed automatically by the make system Program test_modules can also be used to test the genscat BUFR module The Makefile in subdirectory genscat support bufr bufr_tables calls some shell scripts which make symbolic links using the 1n s command of the generic binary BUFR tables B and D under different names There are four different naming conventions in BUFR version 000240 to 000280 and binary files are generated for each of them Further information on the make system is given in the inline comments in the scripts and Makefiles Compilation and linking of the AWDP part is done in a similar manner go to the awdp direc
97. mprehension of future developers and of users interested in the details of the processing Many persons contributed directly or indirectly to the development of the scatterometer software at KNMI Hans Bonekamp Jos de Kloe Marcos Portabella Ad Stoffelen Anton Verhoef Jeroen Verspeek Jur Vogelzang and John de Vries are in alphabetical order the most important contributors Anton Verhoef June 2007 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Chapter 1 Introduction 1 1 Aims and scope The ASCAT Wind Data Processor AWDP is a software package written in Fortran 90 for handling data from the Advanced Scatterometer ASCAT and European Remote Sensing satellite ERS scatterometer instruments Details of these instruments can be found on several web sites and in several other documents see e g Portabella 2002 Stoffelen 1998 and information on the ESA and EUMETSAT web sites AWDP generates surface winds based on level 1b or level 2 ASCAT and ERS data It allows performing the ambiguity removal with the Two dimensional Variational Ambiguity Removal 2DVAR method and it supports the Multiple Solution Scheme MSS The output of AWDP consists of wind vectors which represent surface winds within the ground swath of the scatterometer Input of AWDP is Normalized Radar Cross Section NRCS o data These data may be real time The input files of AWDP are in BUFR
98. n conedistance real Distance of solution to the GMF Table 4 5 Ambiguity data structure Beam data Every WVC contains three beams The information of every beam is stored in the data type beam_type The attributes are listed in table 4 6 Most of the attributes are explained in detail in Wilson Figa Saldana and O Clerigh 2004 The routine init_beam sets all beam data to missing and the routine test_beam checks if the data in the beam are within valid ranges The routine print_beam may be used to print all beam data Attribute Type Description identifier integer Beam number fore 2 mid 3 aft incidence real Incidence angle degrees 0 is vertical 90 is horizontal azimuth real Radar look angle degrees counted clockwise from the south sigma0 real Radar backscatter c in dB noise_val real Noise value in kp_estim_qual kp_estim_qual_ type Flag related to the quality of the Kp estimate sO_usability integer Usability of o 0 good 1 usable 2 bad synt_data_quantity real Amount of synthetic data in a 0 1 synt_data_quality real Quality of used synthetic data in 7 0 1 orbit_quality real Satellite orbit and attitude quality 0 1 solar_reflec real Solar array reflection contamination in o 0 1 telemetry real Telemetry quality 0 1 extrapol_ref pres real Presence of extrapolated reference functions 0 1 land_frac real Land fraction in 0 1 Table 4 6 Beam data structur
99. n overview of the genscat test programs Subdirectory Program name Output file Remarks bufr test_modules testwriting bufr Part of make system grib test_read_GRIB several GRIB handling Compiler Features TestCompiler Features Command line handling convert test_convert test_convert output Wind speed conversion ErrorHandler TestErrorHandler Error handling singletonfft TestSingleton Fast Fourier Transform file TestLunManager TestLunManager output File management BFGS Test_BFGS Minimization num test_numerics test_numerics output Numerical issues pfs test_pfs_ascat Read PFS file sort SortModTest SortModTest output Array sorting datetime TestDateTimeMod TestDateTimeMod output Date and time conversion Table 2 6 Test programs in genscat support 2 7 Documentation Directory awdp doc contains documentation on AWDP including this document Further information can be found in the readme text files and in the comments in scripts Makefiles and source code 21 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Chapter 3 AWDP product specification 3 1 Purpose of program AWDP The ASCAT Wind Data Processor AWDP program has been developed to fully exploit o data from the ASCAT scatterometer instrument on the Metop satellites or the AMI scatterometer instrument on the European Remote Sensing ERS satellites to generate surface winds AWDP may be us
100. nd transformation The minimization problem to find the analysis surface wind field the 2D Variational Data Assimilation problem may be formulated as mind gt JO I a y 6 1 where v is the surface wind field in consideration and J the total cost function consisting of the observational term J and the background term J The solution the analysis surface wind field may be denoted as v Being just a weighted least squares term the background term may be further specified as J O ve B Ev Yy 6 2 where B is the background error covariance matrix The Joss term of the 2DVAR scheme is not simply a weighted least squares term Such a formulation does not closely match the code of the 2DVAR scheme In fact for scientific and technical reasons several transformations are applied to reformulate the minimization problem Description of these transformations is essential to understand the different procedures within the code The interested reader is referred to Vogelzang 2007 6 4 4 Module CostFunction Module CostFunction contains the main procedure for the calculation of the cost function and its gradient It also contains the minimization procedure Table 6 12 provides an overview of the routines Routine Call Description Jt Minimise Total cost function and gradient Jb Jt Background term of cost function Jo Jt Observational term of cost function JoScat Jo Single observation contribution to the cost
101. ndix show the calling tree for the GRIB file handling routines in genscat Routines in black boxes are part of genscat Routines in grey boxes belong to the ECMWF GRIB API library An arrow before a routine name indicates that this part of the calling tree is a continuation of a branch in a previous figure The same arrow after a routine name indicates that this branch will be continued in a following figure set_GRIB_filelist open_GRIB_file read_GRIB_header_info Figure B4 1 Calling tree for GRIB file handling routine set_GRIB_filelist gt inquire_GRIB_filelist get_GRIB_msgnr display_req_GRIB_msg_properties display_GRIB_message_properties Figure B4 2 Calling tree for GRIB file handling routine inguire_GRIB_filelist 92 Doc ID NWPSAF KN UD 005 i Version 2 3 Reference Guide Date February 2014 AWDP User Manual and NWP SAF gt get_from_GRIB_filelist get_GRIB_msgnr display_req_GRIB_msg_properties display_GRIB_message_properties display_req_GRIB_msg_properties display_GRIB_message_properties get_GRIB_data_values get_angle_distance extract_data_from_GRIB_message Figure B4 3 Calling tree for GRIB file handling routine get_from_GRIB_filelist get_colloc_from_GRIB_filelist convert_to_derived_datetime conv_date_to_daycount get_analyse_date_and_times inquire_GRIB_filelist gt check_proximity_to_analyse conv_date_to_daycount inquire
102. ng Application Code Table 85 011082 Model Wind Speed At 10 m m s 86 011081 Model Wind Direction At 10 m Degree True 87 020095 Ice Probability Numeric 88 020096 Ice Age A Parameter dB 89 021155 Wind Vector Cell Quality Flag Table 90 021101 Number Of Vector Ambiguities Numeric 91 021102 Index Of Selected Wind Vector Numeric 92 031001 Delayed Descriptor Replication Factor Numeric 93 011012 Wind Speed At 10 m m s 94 011011 Wind Direction At 10 m Degree True 95 021156 Backscatter Distance Numeric 99 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Number Descriptor Parameter Unit 96 021104 Likelihood Computed For Solution Numeric 97 011012 Wind Speed At 10 m m s 98 011011 Wind Direction At 10 m Degree True 99 021156 Backscatter Distance Numeric 100 021104 Likelihood Computed For Solution Numeric Table C 1 List of data descriptors Note that descriptor numbers 93 96 can be repeated to 144 times depending on the value of the Delayed Descriptor Replication Factor descriptor number 92 100 NWP SAF Doc ID NWPSAF KN UD 005 Version 2 3 AWDP User Manual and Reference Guide Date February 2014 Appendix D Acronyms Name Description AMI Active Microwave Instrument scatterometer on ERS 1 and ERS 2 satellites AR Ambiguity Removal ASCAT Advanced SCATterometer on Metop BUFR Binary Universal Form for the Representation of data C
103. ns_ers_ascat calc_probabilities GetSortIndex test_cell gt Figure A 7 Calling tree for routine invert_wvcs first level T1 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and es D Reference Guide Date February 2014 gt ice_model GetElapsedSystemTime nonbayesian lcemodel calcPoly3 test_cell gt initlceMap RW_IceMap latlon2ij met2uv SetIntegerDate SetIntegerTime printlcePixel calc_plceGivenX ExpandDateTime wT gt calc_aAve ExpandDateTime wT gt ExpandDateTime wT gt calcSubClass smooth iceMap2scat set_knmi_flag printlceMap gt Figure A 8 Calling tree for routine ice_model first level 78 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 gt remove_ambiguities GetElapsedSystemTime InitAmbremModule InitBatchModule InitAmbremMethod InitAmbremBGclosest InitTwodvarModule gt InitDummyMethod GetMaxBatchSize fill_batch get_distance AllocRowsAndCellsAnd InitBatch AllocAndInitBatchRow InitBatchRow InitBatchCell AllocAndlnitBatchCell InitBatchCell InitBatcthAmbi speeddir_to_u speeddir_to_v TestBatch TestBatchRow TestBatchCell DoAmbrem gt select_wind TestBatchCell test_cell gt DeallocBatch DeallocBatchRows DeallocBatchCells DeallocBatchAmbis ExitAmbremMethod ExitTwodvarModule
104. nting the noise in all three ERS or ASCAT beams together Stoffelen and Portabella 2006 This selection depends on the number of independent o values available within the wind vector cell The MLE can be regarded upon as the distance between an actual scatterometer measurement and the GMF in N dimensional measurement space The MLE is related to the probability P that the GMF at a certain wind speed and direction represents the measurement by MLE Pee 5 2 Therefore wind vectors with low MLE have a high probability of being the correct solution On the other hand wind vectors with high MLE are not likely represented by any point on the GMF Details on the inversion problem can be found in Stoffelen and Portabella 2006 Portabella 2002 The AWDP program includes the Multiple Solution Scheme MSS see Portabella and Stoffelen 2001 46 NWP SAF AWDP User Manual and Reference Guide Doc ID Version Date 23 NWPSAF KN UD 005 February 2014 5 2 Routines The inversion module class contains two modules named inversion and post_inversion They are located in subdirectory genscat inversion Tables 5 1 and 5 2 list all routines in the modules Appendix B 1 shows the calling tree for the inversion routines Routine Call Routine Call invert_one_wvc AWDP INTERPOLATE generic fill_wind_quality_code invert_one_wvc interpolateld calc_sigma0 save_inv_input not used interpolated2d calc_sigma0 read_inv_input n
105. nversion AR BUFR IO GRIB IO Total seconds seconds seconds seconds seconds 25000 No 33 8 3 1 46 12500 No 132 16 8 3 160 12500 Yes 156 91 8 3 263 Table 3 2 Approximate times needed by AWDP to process example BUFR files under various input resolutions and options As can be seen from table 3 2 the use of MSS results in slightly larger processing times needed for inversion and in much larger processing times needed for AR The computation time of course increases with increasing resolution The choice of platform compiler and compiler settings will result in a large variation in the 26 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 processing times Using the Portland pgf90 compiler rather than the GNU g95 compiler in the examples in table 3 2 will result in processing times that are 25 to 50 smaller 27 AWDP User Manual and Doc ID NWPSAF KN UD 005 Version 2 3 NWP SAF Reference Guide Date February 2014 Chapter 4 Program Design In this chapter the design of the AWDP program is described in detail Readers to whom only a summary will suffice are referred to the Top Level Design TLD in section 4 1 Readers who really want to know the very detail should not only read the complete chapter but also the documentation within the code 4 1 Top Level Design 4 1 1 Main program The main program AWDP file awdp in the awdp src direc
106. nvestment but is applicable for all scatterometer data The advantage with respect to option in the ambiguity removal occurs only occasionally but always in dynamic atmospheric cases storms or cyclones that are really relevant Both options can be based on AWDP in standard or MSS mode and at various resolutions MSS is somewhat more dependent on the first guess and balance constraints in 2DVAR than the standard AWDP but much less noisy A noticeable advantage is thus obtained by using option 2 and potentially the full hi res benefit of the ASCAT data is achieved The mode of using AWDP thus depends on the opportunities experience and time the user has to experiment with ASCAT data in the NWP system under consideration The AWDP program can of course also be used to create a stand alone wind product e g for nowcasting purposes Such a stand alone ASCAT wind product is a deliverable of the OSI SAF project More information on this project can be found on http www osi saf org 2 3 Installing AWDP AWDP is written in Fortran 90 with a few low level modules in C and is designed to run on a modern computer system under Linux or Unix AWDP needs a Fortran 90 compiler and a C compiler for installation AWDP comes along with a complete make system for compilation In some cases the Makefiles call installation scripts which are written in Bourne shell to enhance portability When compiled AWDP requires about 100 150 Mb disk space In
107. ontribution of this cell to cost function gu Real Derivative of f to u gv Real Derivative of f to v qualflag BatchQualFlagType Quality control flag Table 6 3 Batch data structures To check the quality of the batch a quality flag is introduced for instances of the BatchCellType The flag is set by routine TestBatchCell The attributes of this flag of type BatchQualFlagType are listed in table 6 4 Module BatchMod contains a number of routines to control the batch structure The calls and tasks of the various routines are listed in table 6 5 The batch structure is allocatable because it is only active between the wind retrieval and the ambiguity removal step Attribute Description Missing Quality flag not set Node Incorrect node number specification Lat Incorrect latitude specification Lon Incorrect longitude specification Ambiguities Invalid ambiguities Selection Invalid selection indicator Background Incorrect background wind specification Analysis Incorrect analysis Threshold Threshold overflow Cost Invalid cost function value Gradient Invalid gradient value Table 6 4 Batch quality flag attributes Routine Call Description AllocRowsAndCellsAndInitBatch AllocAndInitBatchRow AllocAndmnitBatchCell Processor AllocRowsAndCellsAndInitBatch AllocAndInitBatchRow Allocation of batch Allocation of batch rows Allocation of batch cells 52 Doc ID NWPSAF KN UD 005 NWP
108. ot used interpolate2dv calc_sigma0 save_inv_output not used interpolate3d calc_sigma0 do_parabolic_winddir_search invert_one_wvc read_LUT calc_sigma0 calc_normalisation calc_sign MLE print_message init_inv_input init_inv_output init_inv_settings_to_default write_inv_settings_to_file get _inv_settings set_inv_settings check_input_data find_minimum_cone_dist get _parabolic_minimum calc_cone_distance calc_dist_to_cone_center convert_sigma_to_zspace get _ers_noise_estimate calc_var_s0 get_dynamic_range get GMF _version_used calc_sigma0 invert_one_wvc invert_one_wvc see B 1 AWDP invert_one_Wwvc AWDP not used AWDP AWDP invert_one_Wwvc invert_one_wvc do_parabolic_winddir_search find_minimum_cone_dist not used invert_one_wvc calc_var_s0 calc_normalisation not used not used see B 1 create LUT C VV test_for_identical_LUTs my_mod my_min my_max my_average get_indices_lowest_local_minimum my_index_max my_exit print_wind_quality_code print_input_data_of inversion print_output_data_of inversion print_in_out_data_of inversion calc_sigma0_cmod4 fl Get_Br_from_Look_Up_Table calc_sigma0_cmod5 calc_sigma0_cmod5_5 calc_sigma0_cmod5_n calc_sigma0_cmod6 calc_sigma0 calc_sigma0 not used see B 1 see B 1 see B 1 invert_one_wvc see B 1 see B 1 see B 1 check_input_data see B 1 not used create LUT C VV calc_sigma0_cmod4 calc_sigma0_cmod4 create LUT C VV create LUT C VV create LUT C
109. outine SFT_PrimeFactors fit Get the factors making up N SFT_Base2 fit Base 2 FFT SFT _ Bases fit Base 3 FFT SFT _Base4 fit Base 4 FFT SFT_Base5 fit Base 5 FFT SFT_BaseOdd fi General odd base FFT SFT Rotate Sft Apply rotation factor Table 6 15 Fourier transform routines Table 6 15 gives an overview of the available routines The figures in Appendix B2 shows the calling tree of the FT routines relevant for 2DVAR Remark the 2DVAR implementation can be made more efficient by using a real to real FFT routine rather than a complex to complex one as implemented now Since AWDP satisfies the requirements in terms of computational speed this has low priority 6 5 The PreScat scheme The PreScat ambiguity removal scheme can be invoked within AWDP by the use of command line option armeth prescat More information on this scheme can be found in Stoffelen de Haan Quilfen and Schyberg 2000 Currently the PreScat scheme can be used only in combination with ERS data 58 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Chapter 7 Module iceModelMod Module iceModelMod is part of the genscat support modules It contains all the routines for initialising reading writing and printing of the SSM I grids for the North Pole and South Pole region 7 1 Background The icemode1 option in AWDP basically fills the fields Ice Probability BUFR item 87 and Ice Age B
110. outine library Satellite Value ERS 1 1 ERS 2 2 Metop 1 Metop B 3 Metop 2 Metop A 4 Metop 3 Metop C 5 Table 4 19 BUFR satellite identifiers Value 142 Parameter sat_instr_ers Instrument AMI scatt 40 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Instrument Parameter Value ASCAT sat_instr_ascat 190 Table 4 20 BUFR instrument identifiers Table 4 21 provides an overview of the different routines and their calls in this module The genscat support routines ymd2julian and julian2ymd are used to provide each row in AWDP with a date time stamp that can be used for sorting easily Routine Call Description ascat_bufr_to_row_data read bufr_ file ASCAT BUFR message into one or more row_types ers_bufr_to_row_data read_bufr_file ERS BUFR message into 19 row_types init_bufr_processing read_bufr_file Initialise module write_bufr_file read_bufr_file AWDP Read a complete BUFR file into row_types row_to_bufr_data write_bufr_file AWDP row_type into ASCAT BUFR message write_bufr_file AWDP Write all row_types into a complete BUFR file Table 4 21 Routines in module awdp_bufr Note that the acquisition date and time of ERS data are modified when they are read in routine ers_bufr_to_row_data An ERS BUFR message contains 19 rows of data which all have the same date and time of acquisition This would cause problems in AWDP
111. principle AWDP may also run under Windows However it needs the BUFR and GRIB API libraries from ECMWF and this poses some restrictions on the systems supported Under Windows one must use a _ free Linux environment like Wubi see http www ubuntu com download desktop windows installer for more information and download To install AWDP the following steps must be taken 1 Copy the AWDP package file AWDP lt version gt tar gz to the directory from which AWDP will be applied and unzip and untar it This will create subdirectories awdp and genscat that contain all code needed see section 2 3 1 and a script called Instal 1lAWDP 10 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 for easy compilation 2 Download the ECMWF BUFR library file bufr_000400 tar gz or another version not earlier than 000240 and not later than 000387 and copy it to directory genscat support bufr Note that library versions 000388 and 000389 are not supported See also section 2 3 2 3 Download the ECMWF GRIB API library file grib_api 1 11 0 tar gz or another version not earlier than 1 9 0 and copy it to directory genscat support grib See also section 2 3 3 4 Go to the top directory and run the InstallAWDP script The script will ask for the compiler used and it will invoke the make system for compilation and linking of the software see also section 2 3 4 AWD
112. ptimization methods Mathematical Programming 45 pp 503 528 e UK Met Office 2001 ERS Products WMO FM94 BUFR Format ER IS UKM GS 0001 Version 4 Issue 2 e Portabella M 2002 Wind field retrieval from satellite radar systems PhD thesis University of Barcelona Available on http www knmi nl scatterometer publications e Portabella M and Stoffelen A 2001 Rain Detection and Quality Control of SeaWinds Journal of Atm Oceanic Technol 18 pp 1171 1183 e Portabella M and Stoffelen A 2004 A probabilistic approach for SeaWinds Data Assimilation Quart J Royal Meteor Soc 130 pp 127 152 e Stoffelen A and M Portabella 2006 On Bayesian Scatterometer Wind Inversion IEEE Transactions on Geoscience and Remote Sensing 44 6 1523 1533 doi 10 1109 TGRS 2005 862502 71 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Tea aa Reference Guide Date February 2014 e Stoffelen A de Haan S Quilfen Y and Schyberg H 2000 ERS scatterometer ambiguity removal scheme comparison OSI SAF report Available on http www knmi nl scatterometer publications e Stoffelen A C M 1998 Scatterometry PhD thesis University of Utrecht ISBN 90 393 1708 9 Available on http www knmi nl scatterometer publications e 6Talagrand O 1991 The use of adjoint equations in numerical modeling of the atmospheric circulation In Automatic Differentiation of Algorithms Theory Implemen
113. r integer ksec1 16 klocalinfo integer ksec1 17 40 Nsec2 integer ksup 2 dimension section 2 nsec2size integer ksec2 1 size section 2 key 46 integer ksec2 2 key Nsec3 integer ksup 3 dimension section 3 nsec3size integer ksec3 1 size section 3 Kreserved3 integer ksec3 2 reserved ksubsets integer ksec3 3 number of reserved subsets kDataFlag integer ksec3 4 compressed 0 1 observed 0 1 Nsec4 integer ksup 4 dimension section 4 nsec4size integer ksec4 1 size section 4 kReserved4 integer ksec4 2 reserved nelements integer ksup 5 actual number of elements nsubsets integer ksup 6 actual number of subsets nvals integer ksup 7 actual number of values nbufrsize integer ksup 8 actual size of BUFR message ktdlen integer Actual number of data descriptors ktdexl integer Actual number of expanded data descriptors ktdlst integer array List of data descriptors ktdexp integer array List of expanded data descriptors values real array List of values cvals character array List of CCITT IA no 5 elements cnames character array List of expanded element names cunits character array List of expanded element units Table 8 4 Attributes of the BUFR message data type BufrDataType The next step is to bring the section data to actual dimensions descriptions and values of data which can be interpreted as physical parameters Therefore instances of BufrSectionsType are transferred to instances of BufrDataType s
114. rDate ExpandIntegerTime ymd2julian Figure B6 1 Calling tree for routine printIcePixel second level gt printlceMap printlceAscat get_lun free_lun printlceQscat get_lun free_lun printSubclass get_lun free_lun printppmvar get_lun free_lun Figure B6 2 Calling tree for routine printIceMap second level 97 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Appendix C ASCAT BUFR data descriptors Number Descriptor Parameter Unit 1 001033 Identification Of Originating Generating Centre Code Table 2 001034 Identification Of Originating Generating Sub Centre Code Table 3 025060 Software Identification Numeric 4 001007 Satellite Identifier Code Table 5 002019 Satellite Instruments Code Table 6 001012 Direction Of Motion Of Moving Observing Platform Degree True 7 004001 Year Year 8 004002 Month Month 9 004003 Day Day 10 004004 Hour Hour 11 004005 Minute Minute 12 004006 Second Second 13 005001 Latitude High Accuracy Degree 14 006001 Longitude High Accuracy Degree 15 005033 Pixel Size On Horizontal 1 M 16 005040 Orbit Number Numeric 17 006034 Cross Track Cell Number Numeric 18 010095 Height Of Atmosphere Used m 19 021157 Loss Per Unit Length Of Atmosphere Used dB m 20 021150 Beam Collocation Flag Table 21 008085 Beam Identifier Code Table 22 002111 Radar Incidence Angle Degree 23 002134 Antenna Beam A
115. ributes list_of GRIB_msgs grib message data array List of messages in file Table 9 4 Attributes of the ist_of _grib_files_type data type for GRIB files 9 4 Libraries Module gribio module uses two libraries from the GRIB API software library of ECMWF libgrib_api a and libgrib_api_f90 a The GRIB API software library of ECMWF is used as a basis to decode GRIB data This software library is explained on http www ecmwf int 70 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Teea aa Reference Guide Date February 2014 References e Belmonte M J Verspeek A Verhoef and A Stoffelen 2012 Bayesian sea ice detection with the Advanced Scatterometer IEEE Transactions on Geoscience and Remote Sensing 2012 50 7 2649 2657 doi 10 1109 TGRS 2011 2182356 e Dragosavac M 1994 BUFR User Guide and Reference Manual ECMWF Available on http www ecmwf int e Figa Saldafia J and Wilson J J W 2005 ASCAT Level 1 Product Format Specification Issue 6 Rev 5 EUMETSAT EPS MIS SPE 97233 Available on http Awww eumetsat int e Giering R 1997 Tangent linear and Adjoint Model Compiler Users manual Max Planck Institut fuer Meteorologie e Hersbach H Stoffelen A and de Haan S 2007 An improved C band scatterometer ocean geophysical model function CMODS Journal of Geophysical Research 112 e Liu D C and Nocedal J 1989 On the limited memory BFGS method for large scale o
116. roduct Generation Function Specification Issue 6 Rev 5 EUMETSAT EUM EPS SYS SPE 990009 Available on http www eumetsat int e WMO 2007 Additions to BUFR CREX Tables for pre operational implementation endorsed by CBS for full operational status on 7 November 2007 updated 04 01 07 pages 55 60 available on http www wmo int web www WMOCodes Updates BUFRCREX Preoperational050107 doc 72 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Appendix A Calling tree for AWDP The figures in this appendix show the calling tree for the AWDP program Routines in white boxes are part of the AWDP process layer Routines in black boxes are part of genscat An arrow gt before a routine name indicates that this part of the calling tree is a continuation of a branch in a previous figure The same arrow after a routine name indicated that this branch will be continued in a following figure iargc_genscat getarg_genscat write_usage read_bufr_file gt X read_pfs_file preprocess gt read_full_res_data gt calibrate_sO get_grib_data invert_wvcs gt ice_model gt remove_ambiguities calibrate_sO x x postprocess write_bufr_file process_cleanup GetElapsedSystemTime Figure A 1 Calling tree for program awdp top level White boxes are cut here and will be continued in one of the first level
117. s option is intended for research activities More information on the file format can be found in the 17 NWP SAF AWDP User Manual and Doc ID NWPSAF KN UD 005 Version 2 3 Reference Guide Date February 2014 writeall handleall nws lt N gt subc lt SC gt mon verbosity lt L gt Fortran code of AWDP Write all data to BUFR output including level 2 input data In the normal near real time processing a mixture of level 1b and recent level 2 data is fed into AWDP in order to provide more data which is beneficial for ambiguity removal Only those data rows which were level 1b input are written to the level 2 output file This option overrides this behaviour and writes all rows to the output file Perform NWP collocation inversion ambiguity removal and output writing in all WVCs By default these steps are done only for WVCs which are level 1b input see the description at the writeall option This option is useful for reprocessing level 2 data Write N wind solutions in BUFR output default 4 The number of wind solutions to be written into the ASCAT BUFR format is flexible due to the use of the so called delayed replication and can be chosen between 1 providing only the selected wind solution and 144 providing all wind solutions in MSS processing Set id of sub centre in each WVC of the BUFR output to SC By default it is copied from input Switch on the monitoring function The mon
118. sion 2 3 Reference Guide Date February 2014 4 3 4 Module awdp_prepost Module awdp_prepost contains the routines to do all the pre and post processing Pre processing consists of the procedures between the reading of the BUFR input and the wind retrieval for the output product This includes sorting and merging and assessments of the quality of the input data Post processing consists of the procedure between the ambiguity removal step and the BUFR encoding of the output The post processing includes the monitoring of the wind data and the setting of some of the flags in the output product Routine Call Description calibrate _s0 AWDP Apply o calibration merge_rows preprocess Merge the data of two input rows monitoring postprocess Monitoring postprocess AWDP Main routine of the post processing pre_inversion_qc preprocess Perform quality checks on input data preprocess AWDP Main routine of the pre processing process_cleanup AWDP Memory management write_binary_output postprocess Write WVC data to a binary output file write_properties postprocess Write some properties of the data into a text file Table 4 23 Routines of module awdp_prepost Table 4 23 lists the tasks of the individual routines AWDP calls preprocess to sort the rows with respect to the acquisition data and time It also checks on the appearance of double rows that is rows which are less than half the nominal cell distance pixel size on horizontal in the
119. so known as the ASCAT research product SZR 3 5 3 Use of full resolution data AWDP offers the possibility to replace the backscatter values in the level 1b product by box averaged g data that are acquired using the full resolution ASCAT level 1 data SZF The beam data o values incidence and azimuth angles which are read from the BUFR or PFS level 1b input file are replaced by average values of the data from the full resolution file which are located within a certain radius typically 10 to 20 kilometers from the WVC location In this way a coastal product can be created See Verhoef et al 2012 for more information on how the box averaged a data are composed It is important to notice that the full resolution data which are fed into AWDP using the szf 1 option must span a time starting at least 150 seconds before the first data in the level lb WVCs and ending no less than 150 seconds after the last data in the level lb WVCs AWDP needs a high resolution land sea mask in order to determine if a full resolution backscatter measurement is over land or sea This information is used in coastal areas to skip backscatter data over land and to use only backscatter data over sea in the averaging of full resolution data The high resolution land sea mask should be available in GRIB format and should have a resolution of approximately 15 km or better The file containing the land sea mask should be present in the list of GRIB files suppl
120. sssecssoseessecee 73 APPENDIX B1 CALLING TREE FOR INVERSION ROUTINES esseoesssecsscceessocecssecesssessoseessecee 83 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date _ February 2014 APPENDIX B2 CALLING TREE FOR AR ROUTINES ssssssssssssssssesssssseesssssseesssssesessssseesessseesssene 86 APPENDIX B3 CALLING TREE FOR BUFR ROUTINES sssssssssssesssssseessssssesssssseesssssneessssseeessane 90 APPENDIX B4 CALLING TREE FOR GRIB ROUTINES o s ssssssssssssesssssseessssssessssnsesssssseesesssseesssane 92 APPENDIX BS CALLING TREE FOR PES ROUTINES sscsssssssssssssesssssseesssssseesssssecsesssneessssseesssane 94 APPENDIX B CALLING TREE FOR ICE MODEL ROUTINES sssssssssssssssssssssessssssseesessseesseese 97 APPENDIX C ASCAT BUFR DATA DESCRIPTORS cssssssssssssssssscssssssscscsssssseccssssnssecsssesnsseesseses 98 APPENDIX D ACRONYMS whose tscicolaces Ae ANEAN A AAE EN ARAN 101 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and es D Reference Guide Date February 2014 Preface Software code for processing satellite data may become very complex On the one hand it consists of code related to the technical details of the satellite and instruments on the other hand the code drives complex algorithms to create the physical end products Therefore the EUMETSAT Satellite Application Facility SAF project for Numerical Weather Prediction NWP has included some explicit ac
121. stalling the GRIB API library AWDP needs the ECMWF GRIB API library for its input operations Only ECMWF is allowed to distribute this software It can be obtained free of charge from ECMWF at the web page 12 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Teea aa Reference Guide Date February 2014 http www ecmwf int products data software grib_api html The package contains scripts for compilation and installation The reader is referred to this site for assistance in downloading and installing the GRIB API Library Directory genscat support grib contains the shell script make grib 1lib It unzips untars and compiles the GRIB API library file which is downloaded from ECMWFE and placed into this directory This script is part of the genscat make system and it is automatically invoked when compiling genscat The current version is tested with GRIB API version 1 11 0 but later versions or earlier but not earlier than 1 9 0 can be used However AWDP is not tested with later versions By default the library for handling GRIB messages that are compressed using the JPEG algorithm is not linked in the compilation process This option can be activated by adding the link option lopenjpeg to the Makeoptions file in directory genscat LINKFLAGS LIB lopenjpeg After this change the software in directories genscat support grib and awdp src needs to be recompiled using the commands make clean and make 2 3
122. t GRIB_msgnr get _from_GRIB filelist get GRIB_msgnr get_from_GRIB filelist get _field_from_GRIB file get _from_GRIB file set_GRIB_filelist add to GRIB filelist open _GRIB _ file get from_GRIB file get from_GRIB filelist get_field_from_GRIB file get from_GRIB file get from_GRIB filelist open_GRIB file dealloc_all_GRIB_messages get_field_from_GRIB_file get_colloc_from_GRIB filelist get_colloc_from_GRIB filelist not used not used not used Retrieve time interpolated GRIB data for a given lat and lon Inquiry of GRIB file list Prints GRIB message info Prints GRIB message info Open GRIB file and get some header information from all messages in this file Read header part of a GRIB message Interpolate data from four surrounding points for a given lat and lon Read all data from GRIB message Clear GRIB message from memory Helper routine Helper routine Table 9 1 Routines of module gribio_module Reading Routine set_GRIB_filelist reads GRIB messages from a list of files decodes them and makes the data accessible in a list of GRIB messages in memory Retrieving Routine get _from_GRIB _filelist returns an interpolated value four surrounding grid points from the GRIB data in the list of files messages for a given GRIB parameter latitude and longitude It is also possible to get a weighted value of all grid points lying within a circle around the latitude and longitude of interest This is used in the l
123. t is located in subdirectory genscat icemodel In the AWDP program the icemodel module is only used in the awdp_icemodel module see section 4 3 8 4 2 4 Module Bufrmod Genscat contains several support modules In particular the BufrMod module is the Fortran 90 32 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and PR ae Reference Guide Date February 2014 wrapper around the BUFR library used for BUFR input and output It is located in subdirectory genscat support bufr Details of this module are described in Chapter 8 In the AWDP program the BufrMod module is only used in the awdp_bufr module see subsection 4 3 2 4 2 5 Module gribio_module The gribio_ module module is the Fortran 90 wrapper around the GRIB library used for GRIB input and collocation of the NWP data with the scatterometer data It is located in subdirectory genscat support grib Details of this module are described in Chapter 9 In the AWDP program the gribio module module is used in the awdp grib and awdp pfs modules see subsection 4 3 5 4 2 6 Support modules Subdirectory genscat support contains more support modules besides Bufrmod and gribio_module The KNMI 2DVAR Ambiguity Removal method requires minimization of a cost function and numerical Fourier transformation These routines are located in subdirectories BFGS and singletonfft respectively and are discussed in more detail in section 6 4 Subdirectory Compiler_Features contains module
124. tables These tables are therefore essential to decode and encode the data 23 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and Teea aa Reference Guide Date February 2014 BUFR tables are issued by the various meteorological centres The largest part of the data descriptors specified in the BUFR tables follows the official BUFR descriptor standards maintained by the World Meteorological Organization WMO http www wmo int However for their different observational products meteorological centres do locally introduce additional descriptors in their BUFR tables Appendix C contains a listing of the data descriptors of the BUFR data input and the BUFR data output of the AWDP program in the ASCAT BUFR product format For more details on BUFR the reader is referred to Dragosavac 1994 ECMWF maintains a library of routines for reading writing and decoding encoding the binary BUFR messages This library forms the basis of the genscat BUFR module and hence the AWDP program BUFR interface see Chapter 8 3 5 2 Product resolution An important feature of the AWDP program is that it may produce a level 2 wind product on different resolutions The resolution of the level 2 wind product is the same as that of the level 1b input product ASCAT data are available in two different resolutions 50 km resolution with 25 km cell spacing also known as the ASCAT operational product SZO and 25 km resolution with 12 5 km cell spacing al
125. tation and Application A Griewank and G Corliess Eds pp 169 180 Philadelphia Penn SIAM e Verhoef A M Portabella and A Stoffelen 2012 High resolution ASCAT scatterometer winds near the coast EEE Transactions on Geoscience and Remote Sensing 2012 50 7 2481 2487 doi 10 1109 TGRS 2011 2175001 e Verhoef A Vogelzang J Verspeek J and Stoffelen A 2013 AWDP Test Report Report NWPSAF KN TV 005 UKMO UK e Verspeek J A Stoffelen A Verhoef and M Portabella 2012 Improved ASCAT Wind Retrieval Using NWP Ocean Calibration IEEE Transactions on Geoscience and Remote Sensing 2012 50 7 2488 2494 doi 10 1109 TGRS 2011 2180730 e Vogelzang J 2007 Two dimensional variational ambiguity removal 2DVAR Report NWPSAF KN TR 004 UKMO UK Available on http www knmi nl scatterometer publications e Vogelzang J Stoffelen A Verhoef A de Vries J and Bonekamp H 2008 Validation of two dimensional variational ambiguity removal on SeaWinds scatterometer data submitted to J Atm Oceanic Technol e de Vries J and Stoffelen A 2000 2D Variational Ambiguity Removal KNMI Feb 2000 Available on http www knmi nl scatterometer publications e de Vries J Stoffelen A and Beysens J 2005 Ambiguity Removal and Product Monitoring for SeaWinds KNMI Available on http www knmi nl scatterometer publications e Wilson J J W Figa Saldafa J and O Clerigh E 2004 ASCAT P
126. ter genscat layer and are described in Chapter 5 to Chapter 9 The appendices of this document contain a complete calling tree of the AWDP program up to and including the genscat layer The appendices also contain a list of ASCAT BUFR data descriptors and a list of acronyms 1 5 Conventions Names of physical quantities e g wind speed components u and v modules e g BufrMod subroutines and identifiers are printed italic Names of directories and subdirectories e g awdp src files e g awdp F90 and commands e g awdp f input are printed in Courier Software systems in general are addressed using the normal font e g AWDP genscat Hyperlinks are printed in blue and underlined e g http www knmi nl scatterometer References are in square brackets with the name of the author italic e g Stoffelen 1998 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF Version 2 3 Reference Guide Date February 2014 Chapter 2 AWDP User Manual This chapter is the user manual of the AWDP program Sections 2 1 and 2 2 give general information about AWDP Section 2 3 provides information on how to install compile and link the AWDP software The command line arguments of AWDP are discussed in section 2 4 Section 2 5 gives information on a script for running AWDP Please note that any questions or problems regarding the installation or use of AWDP can be addressed at the NWP SAF helpdesk at http www nwpsa
127. tes are listed in table 4 10 The routine init nwp_stress param sets the NWP stress parameter data to missing values The routine print_nwp_stress_param may be used to print the stress data Attribute Type Description u real Eastward zonal wind component v real Northward meridional wind component t real Air temperature q real Specific humidity sst real Sea surface temperature chnk real Charnok parameter Sp real Surface pressure Table 4 10 NWP stress parameter data structure Row data The data of a complete row of the swath is stored in the data type row_type see table 4 11 A complete row corresponds to a single BUFR message in the AWDP output The level 1 BUFR data may contain more than one row per BUFR message Attribute Type Description time_stamp integer Time stamp of row data in seconds used for sorting num_cells integer Actual number of WVC s Cell 82 cell type Array of Wind Vector Cells Table 4 11 Row data structure Time data The time_type data type contains a set of 6 integers representing both the date and the time see table 4 12 The routine init_time sets the time entries to missing values The routine test_time tests the validity of the date and time specification see also the cell process flag The routine print_time can be used to print the time information Attribute Type Description year integer 19XX or 20XX month integer 1 12 day integer 1 31 hour integer
128. them to an ASCII file called monitoring_report txt The monitoring parameters are listed in table 4 24 They are calculated separately for three different regions of each swath left and right Note that the monitoring is invoked only if the mon command line option is set 42 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Parameter Description observation Number of Wind Vector Cells in output N land Fraction of WVCs with land flag set ice Fraction of WVCs with ice flag set background Fraction of WVCs containing model winds backscatter_info Fraction of WVCs containing sufficient valid o s for inversion N2 knmi_flag Ratio number of WVCs with KNMI QC flag set N2 wind_retrieval Fraction of N2 that actually contains wind solutions N3 wind_selection Fraction of N3 that actually contains a wind selection N4 big_mle Number of WVCs containing a wind solution but no MLE value avg_mle Averaged over N4 MLE value of 1 wind selection var_qc Fraction of N4 that has the Variational QC flag set rank_1_skill Fraction of N4 where the first wind solution is the chosen one avg_wspd_diff Averaged over N4 difference between observed and model wind speeds rms_diff wspd RMS over N4 difference between observed and model wind speeds wspd_ge 4 Fraction of N4 where the selected wind speed is gt 4 m s N5 rms_diff dir RMS over N5 difference between observed and model wind d
129. tion verbosity In general there are three levels of verbosity specified lt l beas quiet as possible 0 only report top level processing information gt 1 report additional information Of course errors are logged in any case Table 4 4 gives a incomplete list of verbosity parameters They are not all set by the command line option as some of them serve testing and debugging purposes Module Verbosity parameter Ambrem2Dvar TDVverbosity AmbremBGclosest BGverbosity BatchMod BatchVerbosity Ambrem AmbremVerbosity awdp_bufr BufrVerbosity awdp_grib GribVerbosity awdp_icemodel dbgLevel Table 4 4 Verbosity parameters 4 2 Module design for genscat layer 4 2 1 Module inversion The module inversion contains the genscat inversion code Module post inversion contains some routines specific for ERS and ASCAT inversion and quality control The modules are located in subdirectory genscat inversion Details of this module are described in Chapter 5 In the AWDP program the inversion module is only used in the awdp_inversion module see section 4 3 6 4 2 2 Module ambrem The module ambrem is the main module of the genscat Ambiguity Removal code It is located in subdirectory genscat ambrem Details of this module are described in Chapter 6 In the AWDP program the ambrem module is only used in the awdp_ambrem module see section 4 3 7 4 2 3 Module icemodel The module icemodel contains the genscat ice screening code I
130. tivities aiming at enhancing the modularity readability and portability of the processing code For several years the KNMI observation research group has been developing processing code to supply Near Real Time NRT level 2 surface wind products based on the ERS and SeaWinds Scatterometer level 1b Normalized Radar Cross Section data o This work is coordinated and supervised by Ad Stoffelen In the beginning only an adaptation of his ERS code existed Later Marcos Portabella and Julia Figa added modifications and extensions to improve e g the wind retrieval and quality control algorithms In 2003 John de Vries finished the first official release of a processor within the NWP SAF This processor was called the QuikSCAT Data Processor QDP Meanwhile Jos de Kloe has been updating the code for ERS scatterometer wind processing For many parts of the process steps e g the BUFR handling and part of the wind retrieval a large overlap with SeaWinds Data processing coding exists The KNMI Scatterometer Team is working towards generic NRT scatterometer processing As a result a new modular processing code for SeaWinds data was developed within the NWP SAF the SeaWinds Data Processor SDP as successor of QDP Based on the generic code already available for SeaWinds and ERS processing a new ASCAT Wind Data Processor AWDP was developed This document is the corresponding reference manual I hope this manual will strongly contribute to the co
131. tory and enter make As with genscat the make system will execute Makefiles in every subdirectory of awdp The result is the executable awdp in directory awdp src and a symbolic link to this executable in awdp execs AWDP is now ready for use The make system of AWDP doesn t need any further files except the genscat file Makeoptions This is the reason why genscat should be compiled first 14 DocID NWPSAF KN UD 005 NWP SAF AWDP User Manual and PR ae Reference Guide Date February 2014 When recompiling part of AWDP or genscat with the make system for instance when installing a new version of the BUFR library one should be sure to enter make clean first To recompile part of the software invoke the make system where needed The compiler settings from file Makeoptions in directory genscat will be used again If a change in these settings is necessary type make clean in the genscat directory and Makeoptions will be removed Don t forget to rerun the use_ commands to select the right compiler 2 3 5 Environment variables AWDP needs a number of environment variables to be set These are listed in table 2 3 together with their possible values Name Value SBUFR_TABLES genscat support bufr bufr_tables SGRIB_DEFINITION_PATH genscat support grib definitions SINVERSION_LUTSDIR genscat inversion SLUT_FILENAME_C_VV Any existing writable path file name Table 2 3 Environment variables for AWDP The
132. tory is a Unix Linux executable which processes ASCAT BUFR or PFS or ERS BUFR input files The main output consists of BUFR files The output BUFR messages are always in the ASCAT BUFR format for a list of descriptors see appendix C The user may provide arguments and parameters according to Unix command line standards The purpose of the different options is described in the User Manual Chapter 2 When executed the AWDP program logs information on the standard output The detail of this information may be set with the verbosity flag The baseline of processing is described in Figure 4 1 but note that not all of these steps are always invoked Some of them will be skipped depending on the command line options A more detailed representation of the AWDP structure is given in Appendices A and B The first step is to process the arguments given at the command line using the genscat Compiler_Features module Next the AWDP program reads the input file specified in the arguments The BUFR messages or PFS records are read and mapped onto the AWDP data structure see subsection 4 1 3 As part of the pre processing a similar AWDP data structure is created for the output Subsequently the input data are sorted with respect to data acquisition time duplicate rows are merged and the output data structure is filled with level 1b a related data Then the NWP GRIB data wind forecasts land sea mask and sea surface temperature are read and the data ar
133. tput switched off daxpy LBFGS Sum of a vector times a constant plus another vector with loop unrolling ddot LBFGS Dot product of two vectors using loop unrolling MCSRCH LBFGS Line search routine MCSTEP MCSRCH Calculation of step size in line search Table 6 14 Routines in module BFGSMod Some of the error returns of the line search routine MCSRCH have been relaxed and are treated as a normal return Further details can be found in the comment in the code itself 57 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Routines daxpy and ddot were rewritten in Fortran 90 These routines originally written by J Dongarra for the Linpack library perform simple operations but are highly optimized using loop unrolling Routine ddot for instance is faster than the equivalent Fortran 90 intrinsic function dot_product 6 4 8 SingletonFFT_Module Module SingletonFFT Module in directory genscat support singletonfft contains the multi variate complex Fourier routines needed in the 2DVAR scheme A mixed radix Fast Fourier Transform algorithm based on the work of R C Singleton is implemented Routine Call Description SingletonFFT2d SetCovMat Uncondition 2D Fourier transform Uncondition_adj fft SingletonFFT2d Main FFT routine SFT_Permute fit Permute the results SFT PermuteSinglevariate SFT Permute Support routine SFT PermuteMultivariate SFT_Permute Support r
134. ture to an integer value Attribute Bit 2 Description missing Flag not set all bits on collocation 0 1 Beam information originates from different ground stations Table 4 14 Beam collocation flag bits K estimate quality flag The kp_estim_qual_type data type contains the flag indicating the quality of the K estimate Each one of the three beams in a WVC contain an instance of this flag The attributes are listed in table 4 15 The function get_kp_estim_qual interprets an integer flag BUFR input to an instance of kp _estim_qual_type The function set kp _estim_qual transforms an instance of kp_estim_qual_type to an integer flag Attribute Bit 2 Description missing Flag not set all bits on estim_qual 0 1 Inferior quality of K estimate Table 4 15 K estimate quality flag bits Fortran Wind Vector Cell quality flag Every WVC contains a flag for its quality Therefore the ce l_type contains an instance of the wvc_quality_type Table 4 16 gives an overview of its attributes The function get _wvc_quality interprets an integer flag BUFR input to an instance of wvc_quality_type The function get wvc_quality transforms an instance of wvc_quality_type to an integer flag The routine print_wvc_quality may be used to print the bit values of the flag 38 Doc ID Version Date NWPSAF KN UD 005 23 February 2014 NWP SAF AWDP User Manual and Reference Guide Attribute Bit 2 Des
135. utine Call Description calcPoly3 AWDP Calculate a 3 order polynomial ExpandDateTime AWDP Converts a date time to a real ij2latlon not used Calculate lat lon values from SSM I grid coordinates initlceMap AWDP Initialise ice map inv_logit not used Calculate the inverse of the logit of p 1 1 exp p latlon2ij AWDP Calculate SSM I grid coordinates from lat lon values logit not used Calculate the logit of p In p 1 p MAPLL latlon2ij Convert from lat lon to polar stereographic coordinates MAPXY ij2latlon not used Convert from polar stereographic to lat lon coordinates printClass not used Print the ice class sea or ice print_ice_age_ascat notused Print ice age map to graphical ppm file printIceAscat printlceMap Print ASCAT ice map to graphical ppm file printIceMap bayesianIcemodel Print one or more ice map variables to graphical ppm files printlcePixel AWDP Print contents of an ice pixel printIceQscat printlceMap Print QuikSCAT ice map to graphical ppm file printppm_qc not used Print WVC quality flag contents to graphical ppm file printppmvar printlceMap Print variable to ppm file mapped on gray scale printppmvars not used Print three variables to ppm file mapped to an RGB scale printSubclass printlceMap Print the ice subclass to a ppm file RW_IceMap AWDP Read or write an ice map from to a binary restart file wT AWDP Calculate the moving time average function Table 7 1 Routines of module iceModelMod 7 3 Data structures
136. when the rows are sorted with respect to the acquisition date and time Therefore the date and time of each ERS row are recalculated assuming that the 10 middle row of the ERS BUFR message contains the true acquisition time and that subsequent rows are 3 766 seconds apart The time corrections are rounded to an integer number of seconds Hence in the first row 34 seconds are subtracted from the acquisition time in the second row 30 seconds et cetera until in the last 19 row 34 seconds are added to the acquisition time 4 3 3 Module awdp_pfs The module awdp_pfs maps the records in a PFS file on the AWDP data structure It also contains a routine to read in a full resolution PFS file and use the data to calculate averaged beam data which are used to replace 25 12 5 km row data Table 4 22 provides an overview of the different routines and their calls in this module Several routines from the pfs_ascat module in genscat are called from this module to handle the PFS data Appendix B5 shows the calling trees of the routines in module pfs_ascat that are used in AWDP Routine Call Description ascat_pfs_to_row_data read pfs file ASCAT PFS record into one row_type read_full_res_ data AWDP Read full resolution PFS data and replace beam data read_pfs_file AWDP Read a complete PFS level 1b file into row_types Table 4 22 Routines in module awdp_pfs 41 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Ver
137. xtent of the log statements while processing the BUFR file The routines PrintBufrData and CheckBufrData can be used to respectively print and check instances of BufrDataType Open and Close BUFR files The routine open_BUFR_file opens the BUFR file for either reading writemode false or writing writemode true Routine set BUFR fileattributes determines several aspects of the BUFR file and saves these data in an instance of bufr_file_attr_data see table 8 5 Routine get BUFR_nr_of_messages is used to determine the number of BUFR messages in the file Finally routine close_BUFR_file closes the BUFR file 63 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 As said before the underlying encoding and decoding routines originate from the ECMWF BUFR library Appendix B3 shows the calling trees of the routines in module BufrMod that are used in AWDP 8 3 Data structures The data type closest to the actual BUFR messages in the BUFR files is the BufrMessageType see table 8 2 These are still encoded data Every BUFR message consists of 5 sections and one supplementary section After decoding expanding the BUFR messages the data are transferred into an instance of BufrSectionsType see table 8 3 which contains the data and meta data in integer values subdivided in these sections Attribute Type Description buff integer array BUFR message all sections
138. zimuth Degree 24 021062 Backscatter dB 25 021063 Radiometric Resolution Noise Value 26 021158 ASCAT Kp Estimate Quality Code Table 27 021159 ASCAT Sigma 0 Usability Code Table 28 021160 ASCAT Use Of Synthetic Data Numeric 29 021161 ASCAT Synthetic Data Quality Numeric 30 021162 ASCAT Satellite Orbit And Attitude Quality Numeric 31 021163 ASCAT Solar Array Reflection Contamination Numeric 32 021164 ASCAT Telemetry Presence And Quality Numeric 33 021165 ASCAT Extrapolated Reference Function Numeric 34 021166 ASCAT Land Fraction Numeric 35 008085 Beam Identifier Code Table 36 002111 Radar Incidence Angle Degree 37 002134 Antenna Beam Azimuth Degree 38 021062 Backscatter dB 39 021063 Radiometric Resolution Noise Value 40 021158 ASCAT Kp Estimate Quality Code Table 98 AWDP User Manual and Doc ID NWPSAF KN UD 005 NWP SAF i Version 2 3 Reference Guide Date February 2014 Number Descriptor Parameter Unit 41 021159 ASCAT Sigma 0 Usability Code Table 42 021160 ASCAT Use Of Synthetic Data Numeric 43 021161 ASCAT Synthetic Data Quality Numeric 44 021162 ASCAT Satellite Orbit And Attitude Quality Numeric 45 021163 ASCAT Solar Array Reflection Contamination Numeric 46 021164 ASCAT Telemetry Presence And Quality Numeric 47 021165 ASCAT Extrapolated Reference Function Numeric 48 021166 ASCAT Land Fraction Numeric 49 008085 Beam Identifier Code Table 50 002111 Radar Incidence Angle Degree 51 00

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