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OWDP User Manual and Reference Guide

1. verbosity lt L gt 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 Switch off ambiguity removal default is switched on 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 Do not produce BUFR output default is switched on Perform 0 calibration A calibration of the o values is performed i e the backscatter values are changed by a WVC dependent value in order to obtain better calibrated winds See TBD for more details Use the Multiple Solution Scheme for Ambiguity Removal If the Multiple Solution Scheme MSS is switched on OWDP internally works with 144 different solutions for the wind vector If MSS is switched off OWDP calculates two solutions at most MSS is switched off as default 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 2dvar 2DVAR see section 6 4 The default is 2dvar This option generates a second BUFR output file in the KNMI generic wind section format not yet approved by the WMO
2. The number of wind solutions to be written into the KNMI 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 Write selected data of each WVC to a binary output file Data are written to a binary file lt file gt This option is intended for research activities More information on the file format can be found in the Fortran code of OWDP Switch on the monitoring function The monitoring results are written in an ASCII file with the name lt name of BUFR output file gt 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 17 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 or greater also additional information is given The normal mode of operation of OWDP is wind processing i e a HDF5 or BUFR file is read and the various processing steps are performed Besides the wind processing some other modes of operation are available If one of the modes is invoked OWDP internally sets some of the options in order to obtain the desired resu
3. get_inv_settings set_inv_settings get_lun invert_node invert_one_wvc gt init_inv_input get_closest_solution speeddir_to_u speeddir_to_v calc_probabilities GetSortIndex test_cell gt Figure A 6 Calling tree for routine invert_wvcs first level 76 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 gt ice_model GetElapsedSystemTime bayesianlceModel initlceMap RW_IceMap get_lun free_lun latlon2ij gt calclceCoord gt ij2latlon gt get_distance met2uv SetlntegerDate SetIntegerTime ExpandDateTime ExpandDateTime ExpandDateTime calcSubClass iceMap2scat printiceMap gt Figure A 7 Calling tree for routine ice_model first level 77 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 gt remove_ambiguities GetElapsedSystemTime InitAmbremModule InitBatchModule InitAmbremMethod InitAmbremBGclosest InitTwodvarModule gt InitDummyMethod GetMaxBatchSize fill_batch get_distance AllocRowsAndCellsAnd InitBatch AllocAndInitBatchRow InitBatchRow InitBatchCell AllocAndInitBatchCell InitBatchCell InitBatchAmbi speeddir_to_u speeddir_to_v TestBatch TestBatchRow TestBatchCell DoAmbrem gt select_wind TestBatchCell test_cell gt DeallocBatc
4. gt h5d_get_npoints gt h5d_read_int gt h5d_close gt h5d_read_string gt get_I2a_data h5a_get_string gt h5d_open gt h5d_read_int gt h5d_close gt h5d_get_npoints gt h5d_read_float gt h5a_get_string gt h5d_open gt h5d_get_npoints gt h5d_read_int gt h5d_close gt init_ambiguity gt BEE WALD IIe 18 ymd2julian julian2ymd test_cell gt h5g_close gt h5f_close gt Figure A 3 Calling tree for routine read_hdf3_file first level 74 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 gt preprocess GetElapsedSystemTime ymd2julian WVC_ Orientation test_cell gt atm_attenuation Figure A 4 Calling tree for routine preprocess 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 gt Figure A 5 Calling tree for routine get_grib_data first level OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 NWP SAF Reference Guide Date December 2011 gt invert_wvcs GetElapsedSystemTime init_inversion init_inv_settings_to_default
5. Rain Index Numeric 99 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Number Descriptor Parameter Unit 24 013055 Intensity of Precipitation kg m s 25 021122 Attenuation Correction of Sigma 0 from Tb dB 26 002104 Antenna Polarisation Code Table 27 008022 Total Number w r t Accumulation or Average Numeric 28 012063 Brightness Temperature K 29 012065 Standard Deviation Brightness Temperature K 30 002104 Antenna Polarisation Code Table 31 008022 Total Number w r t Accumulation or Average Numeric 32 012063 Brightness Temperature K 33 012065 Standard Deviation Brightness Temperature K 34 021110 Number of Inner beam Sigma 0 Forward of Satellite Numeric 35 005002 Latitude Coarse Accuracy Degree 36 006002 Longitude Coarse Accuracy Degree 37 021118 Attenuation Correction on Sigma 0 dB 38 002112 Radar Look Angle Degree 39 002111 Radar Incidence Angle Degree 40 002104 Antenna Polarisation Code Table 41 021123 SeaWinds Normalised Radar Cross Section dB 42 021106 Kp Variance Coefficient Alpha Numeric 43 021107 Kp Variance Coefficient Beta Numeric 44 021114 Kp Variance Coefficient Gamma dB 45 021115 SeaWinds Sigma 0 Quality Flag Table 46 021116 SeaWinds Sigma 0 Mode Flag Table 47 008018 SeaWinds Land Ice Surface Type Flag Table 48 021117 Sigma 0 Variance Quality Control Numeric 49 021111 Number of Outer beam Sigma 0 Forward of Satellite Numeric 50
6. 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 63 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Attribute Type Description kMasterTableVersion integer ksecl 15 ksubcenter 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 r
7. is given in figure 2 1 The input of the OWDP program is the ISRO level 2a slice HDF5 backscatter product or the OWDP BUFR wind product The ISRO level 2b HDFS5 wind data can also be read and written to BUFR format Besides OSCAT data GRIB input containing land sea mask sea surface temperature and first guess winds over the globe is necessary The OWDP processing chain contains several steps see figure 2 1 1 Pre processing The input file is decoded and the radar backscatter 0 values are written in the data structures of OWDP The slice level backscatter data are averaged to a backscatter value on Wind Vector Cell level 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 and stored with the information of each WVC 3 Inversion The o 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 wind vector The normal scheme allows 4 solutions at most but in the Multiple Solution OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Scheme MSS the maximum number of solutions is 144 Quality
8. 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 62 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 OWDP 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 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
9. 005002 Latitude Coarse Accuracy Degree 51 006002 Longitude Coarse Accuracy Degree 52 021118 Attenuation Correction on Sigma 0 dB 53 002112 Radar Look Angle Degree 54 002111 Radar Incidence Angle Degree 55 002104 Antenna Polarisation Code Table 56 021123 SeaWinds Normalised Radar Cross Section dB 57 021106 Kp Variance Coefficient Alpha Numeric 58 021107 Kp Variance Coefficient Beta Numeric 59 021114 Kp Variance Coefficient Gamma dB 60 021115 SeaWinds Sigma 0 Quality Flag Table 61 021116 SeaWinds Sigma 0 Mode Flag Table 62 008018 SeaWinds Land Ice Surface Type Flag Table 63 021117 Sigma 0 Variance Quality Control Numeric 64 021112 Number of Inner beam Sigma 0 Aft of Satellite Numeric 65 005002 Latitude Coarse Accuracy Degree 66 006002 Longitude Coarse Accuracy Degree 67 021118 Attenuation Correction on Sigma 0 dB 68 002112 Radar Look Angle Degree 69 002111 Radar Incidence Angle Degree 70 002104 Antenna Polarisation Code Table 71 021123 SeaWinds Normalised Radar Cross Section dB 72 021106 Kp Variance Coefficient Alpha Numeric 73 021107 Kp Variance Coefficient Beta Numeric 74 021114 Kp Variance Coefficient Gamma dB 75 021115 SeaWinds Sigma 0 Quality Flag Table 76 021116 SeaWinds Sigma 0 Mode Flag Table 77 008018 SeaWinds Land Ice Surface Type Flag Table 78 021117 Sigma 0 Variance Quality Control Numeric 100 DocID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date D
10. 50 km and 25 km cell spacing A complete specification of the OWDP program can be found in the Product Specification in Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 Chapter 3 The program is based on generic genscat routines for inversion ambiguity removal and BUFR and GRIB file handling These routines are discussed in more detail in Chapter 5 to Chapter 9 10 0mis cow m c EUMETSAT KNMI Figure 2 2 OWDP wind field of hurricane Katia retrieved in the western Atlantic at 50 km WVC spacing on 7 September 2011 approximately 4 15 UTC overlaid on a GOES IR satellite image The orange dots are rejected WVCs the purple dots indicate WVCs for which the land flag is set The two orange arrows near the hurricane centre failed the 2DVAR spatial consistency check 2 2 Modes of using OWDP There are several modes to assimilate the OSCAT data in NWP models using OWDP Anyway the first thing to assure oneself of is the absence of biases by making scatter plots between OSCAT and NWP model first guess for at least wind speed but wind direction and wind components would also be of interest to guarantee consistency for more detailed guidance on bias correction see Vogelzang and Stoffelen 2011 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 The OSCAT wind product available as a deliverable from the EUM
11. A i e iia 41 43 6 Mod le OWAp Inversion ai AA EEEE E EEEE AE a 42 437 Module wdp mbrem saast sitesini tientas ds 42 4 3 8 Module owdp_icemodel atrisina ieee Ea EEEE E Eea E anna none a E 43 4 3 9 NANA A 43 CHAPTERS INVERSION MODULE isscaisssssessocsescoissssscssecsesoosevteosssestocssvessooesbecissessecsesessossecssbessusensots 44 5 1 BACKGROUND ave GERTAE A ase ican Messed 44 5 2 ROUTINES sud totes tods cube a eat odas Lo eet o ctl Git tees colon 45 5 3 ANTENNA DIRECTION pior eieiaeo eiai aea Ea dd DE hdd iea 46 CHAPTER 6 AMBIGUITY REMOVAL MODULE seseessecessssecssocesseceessecsscseessocecsseceessecsscoeessoceessee 47 6 1 AMBIGUITY REMOVAL a a iaa Awe heats 47 6 2 MODULE AMBREM suicida doc iae 47 6 3 MODUEEDATEA MOD aaa 48 6 4 THE KNMI2DVAR SCHEME vetante tenions eose taa aeae aaee BoessesitciascecBisssechsadsdiae dd stecestgdaceevessdeesse 51 6 4 1 TINTO MUCEION sis eee Senn BOE E E E E E E a tials vives 51 6 4 2 Data structure interface and initialisatiON ooonnnninninnnninnnnnnncnncincnccnccnccnncncnnrn 51 6 4 3 Reformulation and transformaliOM oinninniniinnninnnnnnnnnn cinc 54 0 44 Module COSTFUNCIAON St A a a a ds 54 OAS AOJOME Method 2 A A A A A Sse te 54 b467 Structure FUNCHONS e258 re anih aei n Gale aS eaea esa AS R e ia i otek a Bae 55 CAL EMM OA E RSE RE oie lado ee 55 OAS SingletonE ET Module aio tdt lc 56 CHAPTER 7 MODULE ICEMODELMOD u csscccssssscscssssscsssscccessssecscssccccssnsccce
12. Adler gzip and Digital Equipment Corporation DEC Portions of HDF5 were developed with support from the University of California Lawrence Livermore National Laboratory UC LLNL The following statement applies to those portions of the product and must be retained in any redistribution of source code binaries documentation and or accompanying materials This work was partially produced at the University of California Lawrence Livermore National Laboratory UC LLNL under contract no W 7405 ENG 48 Contract 48 between the U S Department of Energy DOE and The Regent s of the University of California University UC LLNL for the operation o DISCLAIMER This work was prepared as an account of work sponsored by an agency of the United States Government Neither the United States Government nor the University of California nor any of their employees makes any warranty express or implied or assumes any liability or responsibility for the accuracy completeness or usefulness of any information apparatus product or process disclosed or represents that its use would not infringe privately owned rights Reference herein to any specific commercial products process or service by trade name trademark manufacturer or otherwise does not necessarily constitute or imply its endorsement recommendation or favoring by the United States Government or the Universi
13. Based on the generic code already available for SeaWinds and ERS processing a new ASCAT Wind Data Processor AWDP was developed 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 November 2011 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Chapter 1 Introduction 1 1 Aims and scope The OSCAT Wind Data Processor OWDP is a software package written in Fortran 90 for handling data from the Oceansat 2 scatterometer instrument OSCAT Details of this instrument can be found in Padia 2010 and on several web sites see e g information on the ISRO web site OWDP generates surface winds based on OSCAT radar backscatter 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 OWDP consists of wind vectors which represent surface winds within the ground swath of the scatterometer Input of OWDP is Normalized Radar Cross Section NRCS o data These data may be near real time The input files of OWDP are in BUFR or Hierarchical Data Format HDF5 Output is written using the SeaWinds BUFR
14. Incidence angle degrees 0 is vertical 90 is horizontal sigma0 real Radar backscatter 0 in dB snr real Signal to noise ratio kp_a real Noise value Kp a as fraction of 1 kp_b real Noise value Kp as fraction of 1 kp_c real Noise value Kp y in dB s0_variance_qc real o variance quality control not used in OWDP s0_quality s0_quality_type Flag related to the quality of the backscatter information 33 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Attribute Type Description s0_mode s0_mode_type Information about beam type sO_surface s0_surface type Information about land or ice presence Table 4 6 Beam data structure Brightness temperature data The btemp type data type contains information on brightness temperatures Every WVC contains two brightness temperatures for the vertically and horizontally polarized beams The attributes are listed in table 4 7 The routine init_btemp sets all brightness temperature data to missing Attribute Type Description k_polar integer Beam polarisation 0 HH pol 1 VV pol tot_num integer Number of slices used in averaging bright_temp real Brightness temperature in K bright temp sd real Standard deviation of brightness temperature Table 4 7 Brightness temperature data structure Cell Data The cell type data type is a key data type in the OWDP program because many processing steps are done on a ce
15. Its configuration very much resembles the SeaWinds instrument and the new OSCAT Wind Data Processor OWDP is heavily based on SDP This document is the corresponding reference manual We hope this manual will strongly contribute to the comprehension of future developers and of users interested in the details of the processing 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 SeaWinds and ASCAT 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
16. 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 ecmw f int Module BufrMod 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 Section 8 2 describes the routines in module BufrMod The public available data stru
17. SAF Version 1 0 01 Reference Guide Date December 2011 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 0 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 as The wind vector solutions correspond to local minima of the MLE function 1 LO O N K MLE 5 1 p With N the number of independent o measurements available within the wind vector cell and K the covariance of the measurement error 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 PR y 5 2 Therefore wind vectors with low MLE have a high probability of being the correct s
18. and commands e g owdp f input are printed in Courier Software systems in general are addressed using the normal font e g OWDP 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 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Chapter 2 OWDP User Manual This chapter is the user manual of the OWDP program Sections 2 1 and 2 2 give general information about OWDP Section 2 3 provides information on how to install compile and link the OWDP software The command line arguments of OWDP are discussed in section 2 4 Section 2 5 gives information on a script for running OWDP Please note that any questions or problems regarding the installation or use of OWDP can be addressed at the NWP SAF helpdesk at http www nwpsaf org 2 1 Why using the OWDP 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 OWDP 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 OWDP and any other wind scatterometer data processor
19. expected Technical information on the KNMI inversion approach can be found in Chapter 5 3 5 6 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 OWDP 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 data assimilation step in order to use the full information content of the scatterometer measurements Further details on the algorithms and their validation can be 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 Further testing for SeaWinds is described in Vogelzang et al 2009 3 5 7 Monitoring For the automatic ingestion of observations into their NWP systems meteorological centres require quality checks on the NRT products For the OSCAT wind product a monitoring 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 fi
20. file bufr_000387 tar gz or another version not earlier than 000240 and copy it to directory genscat support bufr See also section 2 3 3 10 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 3 Download the ECMWF GRIB API library file grib_api 1 9 9 tar gz or another version not earlier than 1 9 0 and copy it to directory genscat support grib See also section 2 3 4 4 Go to the top directory and run the InstallOWDP 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 6 OWDP is now ready for use provided that the environment variables discussed in section 2 3 2 have the proper settings See also sections 2 4 and 2 5 for directions on how to run OWDP 2 3 1 Directories and files All code for OWDP is stored in a file named OWDP 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 OWDP is to be run After unzipping with gunzip OWDP lt version gt tar gz and untarring with tar xf OWDP lt version gt tar the OWDP package is extracted in subdirectories owdp and genscat which are located in the directory where the tar file was located Subdirectories owdp and genscat each contain a number of files and subdirectories A copy of the release notes can also be found in the directory
21. forms of the source or binary code must carry prominent notices stating that the original code was changed and the date of the chang 4 All publications or advertising materials mentioning features or use of this software are asked but not required to acknowledge that it was developed by The HDF Group and by the National Center for Supercomputing Applications at the University of Illinois at Urbana Champaign and credit the contributors 5 Neither the name of The HDF Group the name of the University nor the name of any Contributor may be used to endorse or promote products derived from this software without specific prior written permission from The HDF Group the University or the Contributor respectively 103 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 DISCLAIMER THIS SOFTWARE IS PROVIDED BY THE HDF GROUP AND THE CONTRIBUTORS AS IS WITH NO WARRANTY OF ANY KIND EITHER EXPRESSED OR IMPLIED In no event shall The HDF Group or the Contributors be liable for any damages suffered by the users arising out of the use of this software even if advised of the possibility of such damage Contributors National Center for Supercomputing Applications NCSA at the University of Illinois Fortner Software Unidata Program Center netCDF The Independent JPEG Group JPEG Jean loup Gailly and Mark
22. 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 OWDP Module Description WmoBufrMod WMO standard BUFR data description KnmiBufrMod KNMI BUFR data description EcmwfBufrMod ECMWF BUFR data description Table 8 7 Fortran 90 BUFR modules 65 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Chapter 9 Module gribio_module Module gribio_module is part of the genscat support modules The current ver
23. grib_count_in_file E grib_new_from_file E read_GRIB_header_info grib_get E 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 inquire_GRIB_filelist 91 OWDP User Manual and Doc ID NWPSAF KN UD 006 1 0 01 Version NWP SAF Reference Guide Date December 2011 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 grib_get E grib_is_missing E grib_set E get_angle_distance extract_data_from_GRIB_message Figure B4 3 Calling tree for GRIB file handling routine get_from_GRIB_filelist gt 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_GRIB_filelist gt get_from_GRIB_filelist gt Figure B4 4 Calling tree for GRIB file handling routine get_colloc_from_GRIB_filelist gt dealloc_all_GRIB_messages dealloc_GRIB_message grib_release E grib_close_file E Figure B4 5 Calling tree for GRIB file handling routine dealloc_all_GRIB_messages 92 OWDP Us
24. guaranteed to work on each platform e g by some versions of Cygwin under Windows XP so in some cases it may be necessary to replace the 1n s by cp copy Further information on the make system is given in the inline comments in the scripts and Makefiles Compilation and linking of the OWDP part is done in a similar manner go to the owdp directory and enter make As with genscat the make system will execute Makefiles in every subdirectory of owdp The result is the executable owdp in directory owdp src and a symbolic link to this executable in owdp execs OWDP is now ready for use The make system of OWDP doesn t need any further files except the genscat file Makeoptions This is the reason why genscat should be compiled first When recompiling part of OWDP 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 7 Some remarks for Cygwin users OWDP can be used under Cygwin a Unix emulator running under Windows Installing and running OWDP under Cygwin is almost the same as under Unix or Linux but the followi
25. 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 0 23 minute integer 0 59 second integer 0 59 Table 4 12 Time data structure 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 Sigma0 quality flag The s0_quality_type data type contains the flag indicating the quality of the o Each of the four beams in a WVC contains an instance of this flag The attributes are listed in table 4 14 The function get_s0_quality converts an integer value to the logical flag structure The function set_s0_quality converts a logical flag structure to an integer value Note that only a few bits of this flag are used in OWDP Attribute Bit 2 Description missing Flag not set all bits on usability 15 32768 o measurement not usable noise_ratio 14 16384 Low signal to noise ra
26. of water vapour The attenuation includes atmospheric oxygen water vapour and nominal cloud A mean global cloud cover of 0 1 mm is assumed A table containing the monthly climatological attenuations was kindly provided by NOAA and it is delivered with OWDP in data atm_attn_360_180_12 dat The attenuations are the same that were used for QuikSCAT The one way nadir looking values Amap dB in the table are transformed into an attenuation correction A using the following formula A 2A cos 3 5 where 0 is the beam incidence angle and the attenuation correction is added to the beam 0 value in dB The two way nadir looking values i e without the incidence angle correction are stored in the BUFR output data 3 5 4 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 wind solutions to the GMF also known as Maximum Likelihood Estimator MLE is considered If this value is too large the wind solutions are flagged The MLE threshold depends on WVC number and wind speed The optimum threshold values are determined using the same method as was used for QuikSCAT in the past Portabella 2002 3 5 5 Inversion In the inversion step of wind retrieval the radar backscatter observations in terms of the Normalized Radar Cross Sections as are converted into a set of ambiguous wind v
27. 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 2a b files 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 used to determine if a WVC contains suitable backscatter data for wind inversion Several options for the processing can be invoked noinv icemodel Switch off inversion default is switched on Switch on ice screening When switched off no ice screening is done except when a GRIB file containing sea surface temperature is read The command line option 16 NWP SAF OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 Reference Guide Date December 2011 noamb nowrite calval mss armeth lt meth gt genericws lt N gt binof lt file gt mon
28. owdp docs Tables 2 1 and 2 2 list the contents of directories owdp 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 owdp executable shell script for running OWDP src Source code for OWDP program and supporting routines test Example BUFR and GRIB input files for testing purposes Table 2 1 Contents of directory owdp Name Contents ambrem Ambiguity removal routines ambrem twodvar KNMI 2DVAR ambiguity removal routines icemodel Ice screening routines 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 support datetime Date and time conversion routines support ErrorHandler Error handling routines support file File handling routines support grib GRIB file handling routines support hdf5 HDFS handling routines support num Numerical definitions and number handling routines 11 OWDP User Manual and Doc ID NWPSAF KN UD
29. 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_CFW Set_HelmholzCoefficients Figure B2 1 Calling tree for AR routine nitTwodvarModule 85 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 gt DoAmbrem TestBatch TestBatchRow TestBatchCell AmbRem1stRank 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 set2DVARQualFlag Figure B2 3 Calling tree for AR routine nitObs2dvar 86 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 Do
30. the flag Attribute Description satellite_id Invalid satellite id sat_instruments 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 4 Invalid data in one of the beams model_wind Invalid background wind ambiguity Invalid ambiguities selection Invalid wind selection Table 4 18 Cell process flag bits Fortran Table 4 19 provides an overview of all routines and their calls in module owdp_data Routine Call Description copy_cell Copy all information from one cell into another 38 OWDP User Manual and PociD NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Routine Call Description get s0_mode init beam Convert integer o mode flag to logical structure get s0_quality init beam Convert integer o quality flag to logical structure get s0_surface init beam Convert integer o surface flag to logical structure get wvc_quality_gen init_cell Convert integer WVC quality generic to logical structure get_wve_quality_noaa Convert integer WVC quality KNMI to logical structure init_ambiguity Initialise ambiguity structure init_beam init_cell Initialise beam structure init_cell Initialise cell structure init_icemodel init_cell Initialise ice model structure init nwp_stress param init_cell In
31. the pre processing some checks on the input data are done the atmospheric attenuations are computed and o calibration is performed when applicable Then the NWP GRIB data wind forecasts land sea mask and sea surface temperature are read and the data are collocated with the Wind Vector Cells The next steps are the inversion and the ambiguity removal 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 layer see section 4 3 27 OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 NWP SAF Reference Guide Date December 2011 Read input data Pre processing Post processing Write output BUFR message Figure 4 1 Baseline of the OSCAT Wind Data Processor 4 1 2 Layered model structure OWDP is a Fortran 90 program consisting of several Fortran 90 modules which are linked after their individual compilation The OWPD 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 OSCAT 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 pr
32. 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 OWDP file owdp in the owdp src directory is a Unix Linux executable which processes OSCAT HDF5 or BUFR input files The main output consists of BUFR files The output BUFR messages are in the NOAA BUFR format or in the KNMI BUFR format with generic wind section 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 OWDP 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 OWDP 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 OWDP program reads the input file specified in the arguments The BUFR messages or HDF5 data are read and mapped onto the OWDP data structure see subsection 4 1 3 As part of
33. 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Name Contents support singletonfft FFT routines needed in minimization support sort Sorting routines Table 2 2 Contents of directory genscat Directories owdp 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_ and Set_Makeoptions see 2 3 4 for more details e Scripts for the execution of OWDP in directory owdp execs e Look up tables and BUFR tables needed by OWDP 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 Environment variables OWDP 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 SLUT_FILENAME_KU_HH owdp data lt platform gt nscat2_250_73_51_hh dat SLUT_FILENAME_KU_VV owdp data lt platform gt nscat2_250_73_51_vv dat SLUTSDIR owdp data Table 2 3 Environment variables for OWDP The BUFR_TABLES variable guides OWDP to the BUFR tables needed to re
34. 2DVAR Unpack_ControlVector Uncondition SingletonFFT2d gt Uncondition_adj SingletonFFT2d gt Pack_ControlVector Figure B2 5 Calling tree for AR routine Jt calculation of cost function 87 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 gt 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 88 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 followed by E belong to the ECMWF BUFR library Other routines in grey boxes belong to the bufrio library in C 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 gt 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
35. 3 Brightness Temperature K 54 012065 Standard Deviation Brightness Temperature K 55 002104 Antenna Polarisation Code Table 56 008022 Total Number w r t Accumulation or Average Numeric 57 012063 Brightness Temperature K 58 012065 Standard Deviation Brightness Temperature K 59 021110 Number of Inner beam Sigma 0 Forward of Satellite Numeric 60 005002 Latitude Coarse Accuracy Degree 61 006002 Longitude Coarse Accuracy Degree 62 021118 Attenuation Correction on Sigma 0 dB 63 002112 Radar Look Angle Degree 64 002111 Radar Incidence Angle Degree 65 002104 Antenna Polarisation Code Table 66 021123 SeaWinds Normalised Radar Cross Section dB 67 021106 Kp Variance Coefficient Alpha Numeric 68 021107 Kp Variance Coefficient Beta Numeric 69 021114 Kp Variance Coefficient Gamma dB 70 021115 SeaWinds Sigma 0 Quality Flag Table 71 021116 SeaWinds Sigma 0 Mode Flag Table 72 008018 SeaWinds Land Ice Surface Type Flag Table 73 021117 Sigma 0 Variance Quality Control Numeric 74 021111 Number of Outer beam Sigma 0 Forward of Satellite Numeric 75 005002 Latitude Coarse Accuracy Degree 76 006002 Longitude Coarse Accuracy Degree 77 021118 Attenuation Correction on Sigma 0 dB 78 002112 Radar Look Angle Degree 79 002111 Radar Incidence Angle Degree 80 002104 Antenna Polarisation Code Table 81 021123 SeaWinds Normalised Radar Cross Section dB 82 021106 Kp Variance Coefficient Alpha Numeric 83 021107 Kp Variance Coefficient Beta Numeric 84 021114
36. Attenuation due to rain not used in OWDP btemp 2 btemp_type Brightness temperature data beam 4 beam_type Beam data software id wind integer Software identification of level 2 wind processor 34 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Attribute Type Description 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 num_ambigs_n integer Number of non MSS ambiguities selection integer Index of selected wind vector 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 Table 4 8 Cell 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 ii integer Coordinate on the ice map jj integer Coordinate on the ice map b real Ice coordinate c real Ice coordinate dice real Distance to th
37. C centre is calculated and if this mean value exceeds a threshold of 0 02 the gual_sigma0 flag in wvc_quality is set as well as the land flags in the s0_surface for each beam 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 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 owdp_inversion Module owdp_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 25 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 OWDP Loop over all WVCs and perform inversion Table 4 25 Routines of module awpd_inversion 4 3 7 Module owdp_ambrem Module owdp_ambrem controls the ambiguity removal step of the OWDP 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 26 lists the tasks of the individual routines Routin
38. Chapter 6 In the OWDP program the ambrem module is only used in the owdp_ambrem module see section 4 3 7 4 2 3 Module icemodel The module icemodel contains the genscat ice screening code It is located in subdirectory genscat icemodel In the OWDP program the icemodel module is only used in the owdp_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 wrapper around the BUFR library used for BUFR input and output It is located in subdirectory 31 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 genscat support bufr Details of this module are described in Chapter 8 In the OWDP program the BufrMod module is only used in the owdp_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 API 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 OWDP program the gribio_module module is used in the owdp_grib module see subsection 4 3 5 4 2 6 Module ADF5Mod The HDF5Mod module is the Fortran 90 wrapper around the HDF5 library from the HDF Group used for HDF5 input It is located in subdirectory genscat support hdf5 In the OWDP program the HDF 5Mod modu
39. 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 Ambiguity Removal This procedure identifies the most probable solution using some form of external information OWDP 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 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 OWDP processing scheme The wind vectors and their probabilities after Quality Control may be fed directly in the Data Assimilation step of a Numerical Weather Prediction model Steps 2 and 6 of the processing chain are rather trivial the real work is done in steps 1 3 4 and 5 As further detailed in Chapter 3 OWDP profits from developments in Inversion and output of the full probability density function of the vector wind Multiple Solution Scheme MSS Stoffelen and Portabella 2006 Portabella and Stoffelen 2004 Quality Control QC Portabella and Stoffelen 2001 Portabella 2002 Meteorologically balanced Ambiguity Removal 2DVAR Vogelzang et al 2009 Quality monitoring Capability to process OSCAT data on both
40. ETSAT OSI SAF project could be the starting point for NWP data 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 OWDP could be installed to provide 2DVAR solutions based on the local first guess 2 The OWDP 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 in order to provide the full information content to the data assimilation system This represents some investment but the approach is generic and applicable to all scatterometer data With respect to option 1 this option only occasionally leads to an improved ambiguity removal but often in dynamical atmospheric cases storms or cyclones that are really relevant Both options can be based on OWDP in standard or MSS mode Stoffelen and Portabella 2004 MSS is somewhat more dependent on the balance constraints in 2DVAR or your own data assimilation system than the standard OWDP but much less noisy A substantial advantage is thus obtained by using option 2 and MSS where potentially the full benefit of the OSCAT data is achieved The mode of using OWDP thus depends on the opportunities experience and time the user has to experiment with OSCAT data in the NWP system under consideration for more detailed guidance on scatterometer data assimilation see Vogelz
41. F Version 1 0 01 Reference Guide Date December 2011 Chapter 3 OWDP product specification 3 1 Purpose of program OWDP The OSCAT Wind Data Processor OWDP program has been developed to fully exploit a data from the scatterometer instrument on the Oceansat 2 satellite to generate surface winds OWDP may be used for real time data processing The main application of OWDP is to form the core of an Observation Operator for OSCAT scatterometer data within an operational Numerical Weather Prediction System Program OWDP is also a level 2 data processor It reads data from the ISRO level 2a OSCAT HDFS5 product or from the OSCAT scatterometer BUFR product generated by OWDP itself OWDP applies algorithms for inversion quality control and Ambiguity Removal These methods are mainly developed and published by KNMI The output of OWDP is a BUFR file in the NOAA BUFR format that was used for QuikSCAT data Leidner et al 2000 Additionally a BUFR file containing a generic wind section identical to the wind part of the ASCAT BUFR files can be written This BUFR format also referred to as KNMI BUFR format is not yet approved by WMO 3 2 Output specification The wind vectors generated by OWDP represent the instantaneous mean surface wind at 10 m anemometer height in a 2D array of Wind Vector Cells WVCs with specified size 50 x 50 km or 25 x 25 km depending on the cell spacing of the input product These WVCs are part of the gr
42. Kp Variance Coefficient Gamma dB 85 021115 SeaWinds Sigma 0 Quality Flag Table 86 021116 SeaWinds Sigma 0 Mode Flag Table 87 008018 SeaWinds Land Ice Surface Type Flag Table 88 021117 Sigma 0 Variance Quality Control Numeric 89 021112 Number of Inner beam Sigma 0 Aft of Satellite Numeric 90 005002 Latitude Coarse Accuracy Degree 91 006002 Longitude Coarse Accuracy Degree 92 021118 Attenuation Correction on Sigma 0 dB 93 002112 Radar Look Angle Degree 94 002111 Radar Incidence Angle Degree 98 DocID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 Number Descriptor Parameter Unit 95 002104 Antenna Polarisation Code Table 96 021123 SeaWinds Normalised Radar Cross Section dB 97 021106 Kp Variance Coefficient Alpha Numeric 98 021107 Kp Variance Coefficient Beta Numeric 99 021114 Kp Variance Coefficient Gamma dB 100 021115 SeaWinds Sigma 0 Quality Flag Table 101 021116 SeaWinds Sigma 0 Mode Flag Table 102 008018 SeaWinds Land Ice Surface Type Flag Table 103 021117 Sigma 0 Variance Quality Control Numeric 104 021113 Number of Outer beam Sigma 0 Aft of Satellite Numeric 105 005002 Latitude Coarse Accuracy Degree 106 006002 Longitude Coarse Accuracy Degree 107 021118 Attenuation Correction on Sigma 0 dB 108 002112 Radar Look Angle Degree 109 002111 Radar Incidence Angle Degree 110 002104 Antenna Polarisation Code Table 111 021123 SeaWinds Normalised Radar Cross Sect
43. L ii li i 1e0 w 140 w 120 w 100 w aw eow aew 20 w or 20E 40 E 0 E 80 E 100 E 120 E 140 E 160 E Figure 2 3 Global coverage of the test run Wind speed results for the 50 km product are shown Directory genscat support bufr contains a test program named test_modules It is invoked by the genscat make system to construct the BUFR tables required by OWDP 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 19 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and asin 1001 Reference Guide Date December 2011 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 gens
44. 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 3 Conventions for the wind direction 46 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 WVC 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 WVC simply called ambiguities result from the wind retrieval processing 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 backgro
45. NWP SAF Satellite Application Facility for Numerical Weather Prediction Document NWPSAF KN UD 006 Version 1 0 01 December 2011 OWDP User Manual and Reference Guide Anton Verhoef Jur Vogelzang Jeroen Verspeek and Ad Stoffelen KNMI De Bilt the Netherlands bli Numer AZ M O SN ECMWF 2 Royal Netherlands M ETEO FRA N Cc E A ad et ffice Th pe Toujours un temps d avance Enviro l nment OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 OWDP 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 16 December 2003 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 2011 EUMETSAT All Rights Reserved Change record Version Date Author changed by Remarks 1 0 Dec 2011 Anton Verhoef First draft Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and yrs lt 1001 Reference Guide Date December 2011 Contents SA A O ON 1 O ON 4 CHAPTER 1 INTRODUCTION fiiisssc cssccccccversaccsssnceccenssasocssaccsitvenssodseseoncgstssdesdaeesescuutavoesbeesd socectonseassonses 5 1 1 AIMS AND SCOPE ia ocio enana ci
46. S level 2a backscatter data from ISRO are organised in slices see Padia 2010 The slices need to be beamwise accumulated to a Wind Vector Cell WVC level before wind inversion can be done The individual slice contributions are averaged using DO a 3 1 Ya G Ss oO where o is the WVC backscatter 0 is the slice backscatter and as is the slice K alpha The weights as were found to be proportional to the estimated transmitted power contained in a slice and thus the above weighting relates to a summation over backscattered power The Sigma0 Quality Flag present in the HDFS data is evaluated and slice data with one of the following flags set are skipped e ois poor e K is poor e Invalid footprint e Footprint contains saturated slice The WVC K values a p and y are computed from the slice K s as a Ea p Sa Er 62 S the WVC received power P is computed from the slice received power as PH Pos P 2 SNR P 3 3 S and the WVC SNR is calculated as 23 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and yrs 1001 Reference Guide Date December 2011 SNR P 2_ 3 4 Now K a B SNR y SNR is obtained for each WVC view 3 5 3 Atmospheric attenuation The Ku band radiation from OSCAT is attenuated by the atmosphere Climatological values of this attenuation were determined as a function of location and time of the year Wentz 1996 The attenuation is based on a climatology
47. _adj fft SingletonFFT2d Main FFT routine SFT_Permute fit Permute the results SFT PermuteSinglevariate SFT_Permute Support routine SFT PermuteMultivariate SFT_Permute Support routine SFT_PrimeFactors fit Get the factors making up N SFT_Base2 fit Base 2 FFT SFT_Base3 fit Base 3 FFT SFT_Base4 fit Base 4 FFT SFT_Base5 fit Base 5 FFT SFT_BaseOdd fii 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 OWDP satisfies the requirements in terms of computational speed this has low priority 56 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Chapter 7 Module iceModelMod Module iceModelMod is part of the genscat support modules It contains all the Bayesian statistics routines including the routines for spatial and temporal averaging It also contains all the routines for initialising and printing of the SSM I grids for the North Pole and South Pole region 7 1 Background The distribution of backscatter points combination of DO O mai and alyva from ocean and sea ice surfaces is notably different The ice screening method u
48. _close bufr_error Figure B3 2 Calling tree for BUFR handling routine close_BUFR_file 89 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 gt get_BUFR_message get_expected_BUFR_msg_size bufr_read_allsections bufr_error bufr_get_section_sizes bufr_swap_allsections ExpandBufrMessage BUS012 E PrintBufrErrorCode CheckBufrTables get_file_size encode_table_b encode_table_d BUFREX E FillBufrSecData BUSEL E Figure B3 3 Calling tree for BUFR handling routine get BUFR_message gt save_BUFR_message EncodeBufrData CheckBufrData FillBufrData PrintBufrErrorCode Figure B3 4 Calling tree for BUFR file handling routine save BUFR file 90 OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 NWP SAF Reference Guide Date December 2011 Appendix B4 Calling tree for GRIB routines The figures in this appendix show the calling tree for the GRIB file handling routines in genscat Routines in black boxes are part of genscat Routines in grey boxes followed by E belong to the ECMWF GRIB API library 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 gt set_GRIB_filelist open_GRIB_file grib_open_file E
49. ad the input and write the output The SGRIB_DEFINITION_PATH variable is necessary for a proper functioning of the GRIB decoding software The variables SLUT_FILENAME_KU_HH and SLUT_FILENAME_KU_VV point OWDP to the correct binary Ku band GMF lookup tables at HH and VV polarisation respectively They should contain a file name including a valid path NSCAT lookup tables are delivered with OWDP in big endian and little endian binary formats the lt platform gt part in the paths should be set to big_endianorlittle_endian depending on your computer platform type The variable SLUTSDIR points OWDP to a directory containing some look up tables that are used to normalise the inversion residuals and to compute atmospheric attenuations for the Ku band radar data The necessary tables are delivered with OWDP 12 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 2 3 3 Installing the BUFR library OWDP 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 t
50. alis triada 5 1 2 DEVELOPMENT OF OW DP arnee r a EEE 5 1 3 TESTING OW DP ites ics cece A E AE A E daras 5 1 4 USER MANUAL AND REFERENCE GUIDE cccccssssecesssececsecececseceeceeaeeeceesaeeecseeeeeesaeeecsesaeeseneeeeees 6 1 5 CONVENTIONS soso se5 csncsnsccsetisbastostycngoareesig tort bees devbaniadusbveleccsahiednvedbes A 6 CHAPTER 2 OWDP USER MANUAL ueiccscssssssssveasssssscnsocseseiecsssssscensecsessedessecessevtsscosestsessbestosssiesioosses 7 2 1 WHY USING THE OWDP PROGRAM 00 cccssscessscceceessececsecceceesseeeecsessececeaeesessueeecsesaeeeseeeeeesesaeeeengas 7 2 2 MODES OP USING O WDB 8 2 a tuaths covashaues Riebbubseeseeeas a a e A Sessa 9 2 3 INSTALLING OW DP iii EEA E ada diia 10 2 314 Directories sand files A A A A A E AA 11 23 2 ENVIFONMENE VATIGDIES a aiii 12 23 321 Installing the BUFR BAY corcel 13 2 3 4 Installing the GRIB API iDr ary ccccecceccecccseeceeeesseeecuseeseeseeseeseceeecseesceaesseeseceeecnseeeeeseneeetens 13 2 3 3 Installing the HDES brary it tt it id 13 2 3 6 Compilation and linking ceccccceccceceecceseesceseeseeseeseeeecseesceecseescesecseeseseeecseesceaeeseesesteveeeneenen 14 2 3 7 Some remarks for Cygwin USEYS cccccccccccssesssseccsseesceecseesceseeseeeceeeecnseesceseeseeseceveecnseeeenseereeaees 15 2 4 COMMAND LINE OPTIONS 2 ooctcccncado gt dececee doit E ani se bee bbsoteaovoeacsieee 16 2 5 SCRIPTS iii ib A AAA Sete 18 2 6 TEST DATA AND TEST PROGRAMS 1 ccssscccssssecec
51. ang and Stoffelen 2011 The OWDP program can of course also be used to create a stand alone wind product e g for nowcasting purposes Such a stand alone OSCAT 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 OWDP OWDP 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 OWDP needs a Fortran 90 compiler and a C compiler for installation OWDP 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 OWDP requires about 150 200 Mb disk space In principle OWDP 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 Unix emulator like Cygwin see http www cygwin com for more information and download and section 2 3 7 for some directions To install OWDP the following steps must be taken 1 Copy the OWDP package file OWDP lt version gt tar gz to the directory from which OWDP will be applied and unzip and untar it This will create subdirectories owdp and genscat that contain all code needed see section 2 3 1 and a script called Instal lOWDP for easy compilation 2 Download the ECMWF BUFR library
52. asges 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 64 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and sion lt 1001 Reference Guide Date December 2011 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 genscat 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
53. atch AllocAndInitBatchRow Allocation of batch Allocation of batch rows Allocation of batch cells 50 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 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 va
54. atter Distance Numeric 111 021104 Likelihood Computed For Solution Numeric Table C 1 List of data descriptors Note that descriptor numbers 93 96 can be repeated 1 to 144 times depending on the value of the Delayed Descriptor Replication Factor descriptor number 92 101 NWP SAF Doc ID NWPSAF KN UD 006 Version 1 0 01 December 2011 OWDP User Manual and Reference Guide Date Appendix D Acronyms Name Description AR Ambiguity Removal ASCAT Advanced SCATterometer on MetOp BUFR Binary Universal Form for the Representation of data C 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 HDF5 Hierarchical Data Format version 5 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 a NWP Numerical Weather Prediction OSI Ocean and Sea Ice QC Quality Control RMS Root Mean Square SAF Satellite Application Facility SSM I Special Sen
55. atures are avoided As a consequence some tasks must be transferred to shell scripts The make system consists of two parts one for OWDP 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 simply 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 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 1ib for compilation of the BUFR library see 2 3 3 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 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 Symbolic links are not
56. cat support grib definitions Subdirectories Compiler_Features convert ErrorHandler singletonfft file BFGS num hdf 5 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 output files for comparison Table 2 6 gives an 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 hdf5 TestHDF5 Read HDFS 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 owdp doc contains documentation on OWDP including this document Further information can be found in the readme text files and in the comments in scripts Makefiles and source code 20 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SA
57. ce module see table 6 2 Figure 6 1 shows schematically the interdependence of the various modules for Ambiguity Removal Routine Call Description InitAambremModule OWDP Initialization of module Ambrem InitAmbremMethod OWDP Initialization of specified AR scheme DoAmbrem OWDP 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 OWDP 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 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
58. cemodel ice model Implementation of the Bayesian ice model calc_aAve bayesianIcemodel Calculate space time averaged values of ice parameter a calc_aSd bayesianIcemodel Calculate the standard deviation of ice parameter a calclceCoord calc_icemapping Calculate ice coordinates and distance to ice line calclcelineParms calc_icemapping calclceCoord bayesianIcemodel Calculate distance to ice line from given a s Calculate the mapping from ice map to swath data calc_plceGivenX bayesianlcemodel Calculate the ice a posteriori probability calcSubClass bayesianIcemodel Calculate the subclass of a pixel on the ice map getClass updatelcePixel Calculate the ice type of a pixel on the ice map getPx updatelcePixel Get the probability of ice iceMap2scat bayesianIcemodel Update cell data structure with information in ice map ice_model OWDP Main routine of ice screening scat2iceMap bayesianIcemodel Update the ice map with the information in cell data smooth bayesianIcemodel Smooth the ice map updatelcePixel scat2iceMap Update a pixel on the ice map Table 4 27 Routines of module owdp_icemodel 4 3 9 Module owdp Module owdp is the main program of OWDP 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 43 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP
59. ctures 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 OWDP Initialization routine set BUFR _fileattributes OWDP Initialization routine open_BUFR_file OWDP Opens a BUFR file get BUFR_nr_of messages OWDP Inquiry of BUFR file get BUFR message OWDP Reads instance of BufrDataType from file get expected BUFR_msg size get BUFR message Inquiry of BUFR file ExpandBufrMessage get BUFR message Convert from BufrMessageType to BufrSectionsType 61 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and lesion 1001 Reference Guide Date December 2011 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_table_b CheckBufrTables encode_table_d CheckBufrTables FillBufrSecData ExpandBufrMessage Convert from BufrSectionsType to BufrDataType close BUFR file OWDP Closes a BUFR file BufrReal2Int OWDP Type conversion BufrInt2Real OWDP Type conversion save BUFR_message OWDP Saves instance of BufrDataT
60. d H Figure B5 6 Calling tree for HDF5 file handling routine h3d_read_ int 94 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and sion 1001 Reference Guide Date December 2011 gt h5d_read_string h5t_close_c H5Tclose H Figure B5 7 Calling tree for HDF5 file handling routine h5d_read_string gt h5d_read_float h5d_read_float_c H5Dread H Figure B5 8 Calling tree for HDFS file handling routine h5d_read_float gt h5d_close h5d_close_c H5Dclose H Figure B5 9 Calling tree for HDFS file handling routine A3d_close gt h5g_close h5g_close_c H5Gclose H Figure B5 10 Calling tree for HDFS5 file handling routine A3g_close gt h5f_close h5f_close_c H5Fclose H Figure B5 11 Calling tree for HDFS file handling routine h5f close 95 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and yrs 1001 Reference Guide Date December 2011 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 gt 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 gt latlon2ij mapll Figure B6 1 Calling tree for ro
61. data structures are defined in module TwoDvarData and the routines in this module are listed in table 6 10 Attribute Type Description alpha Real Rotation angle cell Integer Store batch cell number row Integer Store batch row number igrid Integer Row index jerid 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 52 OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 NWP SAF Reference Guide Date December 2011 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 Ncontrol Integer Size of control vector Tabl
62. e 6 9 The TDV_Type data structure Routine Call Description TDV Init InitTwodvarModule Initialization of 2DVAR grid and preparations Set_HelmholzCoefficients 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 observatio
63. e Call Description fill_batch remove_ambiguities Fill a batch with observations remove_ambiguities OWDP Main routine of ambiguity removal select_wind remove_ambiguities Final wind selection 42 Doc ID Version Date NWPSAF KN UD 006 1 0 01 December 2011 NWP SAF OWDP User Manual and Reference Guide Table 4 26 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 OWDP 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 optimal dimensions for FFT The routine remove_ambiguities performs the actual ambiguity removal Finally select wind passes the selection to the output WVCs 4 3 8 Module owdp_icemodel Module owdp_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 2011 The ice screening is done before the ambiguity removal step Table 4 27 provides an overview of the routines and their calls in this module Routine Call Description bayesianl
64. e HDF5Mod module in genscat are called from this module to handle the HDF5 data Appendix B5 shows the calling trees of the routines in module ADF5Mod that are used in OWDP Routine Call Description get l2a data read_hdf5 file Get level 2a specific information from HDF5 file get 12b_data read_hdf5 file Get level 2b specific information from HDFS file read_hdf5 file OWDP Read a complete HDFS5 level 2a or level 2b file into row_ types Table 4 21 Routines in module owdp_hdf5 4 3 4 Module owdp_prepost Module owdp_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 completion of missing information 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 atm_attenuation preprocess Compute climatological atmospheric attenuations calibrate_s0 OWDP Apply 0 calibration monitoring postprocess Monitoring postprocess OWDP Main routine of the post processing preprocess OWDP Main routine of the pre processing process_cleanup OWDP Memory management write_binary_output postprocess Write WVC data to a binary output file write_prop
65. e ice line 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 OWDP The attributes 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 OWDP output 35 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Attribute Type Description num_cells integer Actual number of WVC s in this row Cell 76 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
66. e of the grid land fractions where each grid land fraction has a weight of 1 r 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 67 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 before and two after are provided 1 AZ 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 underl
67. eModelMod 7 3 Data structures 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 of ice pixels and represents an entire ice map IceMapType This could be either an ice map of the 58 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 plceGivenXave real Average a posteriori ice probability sumWeightST real Sum of weight factors timePixelNow DateTime Date time of latest ice pixel update timePixelPrev DateTime Date time of previous ice pixel update 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 North Pole or South Pole use_sst logical Control whether sea surface temp is to be used timeMapNow DateTime Date time of latest ice map
68. ead_bufr_file gt read_hdf5_file gt calibrate_sO preprocess gt get_grib_data gt invert_wvcs gt ice_model gt remove_ambiguities gt postprocess gt calibrate_sO write_bufr_file gt process_cleanup GetElapsedSystemTime Figure A 1 Calling tree for program owdp top level White boxes are cut here and will be continued in one of the first level or second level calling trees in the next figures Black boxes with light text indicate genscat routines 12 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 gt read_bufr_file GetElapsedSystemTime init_bufr_processing set_BUFR_fileattributes open_BUFR_file gt get_BUFR_nr_of_messages get_BUFR_message gt bufr_to_row_data_noaa init_cell gt BufrReal2Int get_wvc_quality_noaa get_s0_quality get_s0_mode get_s0_surface test_cell gt bufr_to_row_data_gen init_cell gt BufrReal2Int get_s0_quality get_s0_mode get_s0_surface get_wvc_quality_gen test_cell gt close_BUFR_file gt Figure A 2 Calling tree for routine read_bufr_file first level 73 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and asin 1001 Reference Guide Date December 2011 gt read_hdf5_file GetElapsedSystemTime init_hdf5_module h5f_open gt h5g_open gt h5a_get_string gt h5d_open
69. eall 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 7 2 Routines Table 7 1 provides an overview of the routines in module iceModelMod Routine Call Description calcPoly3 not used Calculate a 3 order polynomial ExpandDateTime OWDP Convert a date time to a real ij2latlon OWDP Calculate lat lon values from SSM I grid coordinates initlceMap OWDP Initialise ice map inv_logit not used Calculate the inverse of the logit of p 1 1 exp p latlon2ij OWDP Calculate SSM I grid coordinates from lat lon values logit not used Calculate the logit of p In p 1 p printClass not used Print the class of an ice pixel printlceAscat printlceMap Print ice map for ASCAT to graphical ppm file printlceMap OWDP Print one or more ice map variables to graphical ppm files printlcePixel not used Print ice pixel information printIceOscat printlceMap Print ice map for QuikSCAT OSCAT to graphical ppm file printppmcolor printIceMap Print variable on ice map to ppm file using colour index printppmvar printlceMap Print variable on ice map to ppm file mapped on gray scale RW_IceMap OWDP Read or write an ice map from to a binary restart file wT OWDP Compute moving time average function Table 7 1 Routines of module ic
70. ecember 2011 Number Descriptor Parameter Unit 79 021113 Number of Outer beam Sigma 0 Aft of Satellite Numeric 80 005002 Latitude Coarse Accuracy Degree 81 006002 Longitude Coarse Accuracy Degree 82 021118 Attenuation Correction on Sigma 0 dB 83 002112 Radar Look Angle Degree 84 002111 Radar Incidence Angle Degree 85 002104 Antenna Polarisation Code Table 86 021123 SeaWinds Normalised Radar Cross Section dB 87 021106 Kp Variance Coefficient Alpha Numeric 88 021107 Kp Variance Coefficient Beta Numeric 89 021114 Kp Variance Coefficient Gamma dB 90 021115 SeaWinds Sigma 0 Quality Flag Table 91 021116 SeaWinds Sigma 0 Mode Flag Table 92 008018 SeaWinds Land Ice Surface Type Flag Table 93 021117 Sigma 0 Variance Quality Control Numeric 94 025060 Software Identification Numeric 95 001032 Generating Application Code Table 96 011082 Model Wind Speed At 10 m m s 97 011081 Model Wind Direction At 10 m Degree True 98 020095 Ice Probability Numeric 99 020096 Ice Age A Parameter dB 100 021155 Wind Vector Cell Quality Flag Table 101 021101 Number Of Vector Ambiguities Numeric 102 021102 Index Of Selected Wind Vector Numeric 103 031001 Delayed Descriptor Replication Factor Numeric 104 011012 Wind Speed At 10 m m s 105 011011 Wind Direction At 10 m Degree True 106 021156 Backscatter Distance Numeric 107 021104 Likelihood Computed For Solution Numeric 108 011012 Wind Speed At 10 m m s 109 011011 Wind Direction At 10 m Degree True 110 021156 Backsc
71. ector 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 The NSCAT2 GMF is delivered with OWDP it is the same GMF that also proved to be successful in the SDP processing software for QuikSCAT The OWDP 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 6 is applied with a much larger set of wind vector solutions The output BUFR format can 24 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 Stoffelen and Portabella 2006 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 2009 and for OSCAT the same can be
72. ed 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 C objects SGENSCAT_SHLINK _ Reference to linker for shared objects Table 2 4 Environment variables for compilation and linking Script Fortran C Remarks compiler compiler use_g95 g95 gcc GNU compilers by Andy Vaught use_gfortran gfortran gcc GNU GCC compiler collection use_ifort ifort igg 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 173 use_g95 bsh the dot being absolutely necessary in order to apply the compiler selection 14 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 OWDP 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 fe
73. eeecceeccsesseeecaenseesecaessecaeeeeceaeeseeaeeaeneeeneeeree 28 BASS DA SW UCHUL Coes re roves esta ce Pica te otte aaas vece ais 29 4 1 4 Quality flagging and error NAandling n cccccccccccccccccesceseescesesseesecseeeecuseesensesseesecieeeenseeseeseeseerees 30 AAS VEPDOSU ti ind EE EEE TEE T E 30 4 2 MODULE DESIGN FOR GENSCAT LAYER ccccesssssscecececeesescaececececeesaaececececsesaaeceeeceeseneaaeaeeeeeeeenes 31 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 4 2 1 MO UIC TNVETSTON A Shee acta elevate Ses E ea ea ada tdt 31 ADD MODULE GIN DICH serate enana A das pa nok 31 423 Modul tc mod els Wa ada tadas 31 4 240 Module B frmod oia eS id td e Aen eae ee 31 4 2 5 Module gribio module i ciccccccccccsccesesssssessessesecsesseccesscssesseesecsesseceeeeceaeesessecseeeenseeeenaeeeeeaees 32 4236 Module HDES Modas lalala asas dol ce lavdd eines lt del taa side aa 32 LADA SUPPOFL MOGUICS AA A A A A AA tienes Peet 32 4 3 MODULE DESIGN FOR PROCESS LAYER ccssssesssscesesssececeeseececsneeecessaececsesaeeecseeeesesaeeecseaaeeecseeeenes 33 4 3 1 Module owdp dtd ix castes ii ok eile heh weve atta easter a en oats 33 4 3 2 Module owdp buferini oder heien aan tata lenin nese 39 43 37 Module OWdp Macias ati Supe arado tidad 40 4 34 Moduleowdp preposti esiones eiei aeaiia i a E gfe rb EE e E EE votes 40 473 9 Module OWA De Br iD i ts
74. er Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Appendix B5 Calling tree for HDFS5 routines The figures in this appendix show the calling tree for the HDF5 file handling routines in genscat All routines are part of genscat as indicated by the black boxes Routines in grey boxes followed by H belong to the HDFGROUP HDFS library Other routines in grey boxes belong to the hdfSio library in C An arrow gt 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 gt h5f_open h5f_open_c H5Fopen H H5Eset_auto H Figure B5 1 Calling tree for HDF5 file handling routine A5f_open gt h5g_open h5g_open_c H5Gopen H Figure B5 2 Calling tree for HDF5 file handling routine h5g_open gt h5d_open h5d_open_c H5Dopen H Figure B5 3 Calling tree for HDF5 file handling routine h5d_open 93 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and sion 1001 Reference Guide Date December 2011 gt h5a_get_string Figure B5 4 Calling tree for HDF5 file handling routine h5a_get_string gt h5d_get_npoints Figure B5 5 Calling tree for HDF5 file handling routine h5d_get_npoints gt h5d_read_int h5d_read_int_c H5Drea
75. erties postprocess Write some properties of the data into a text file Table 4 22 Routines of module owdp_prepost Table 4 22 lists the tasks of the individual routines OWDP calls preprocess to compute information not present in the level 2a data like satellite motion direction time to edge and 40 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 atmospheric attenuation The wvc_quality flag is initialised and the and and ice flags in wvc_quality are set according to the settings of the corresponding flags in the beam s0_ surface flags The next step is the calibration of the o s in calibrate_s0 Based on the results of instrument Ocean Calibration a bias is added to the backscatter values Note that the calibration is done again in the reverse order after the post processing in order to write the as to output as plain copies of the input os More information about the calibration can be found in TBD The monitoring which is performed as part of the post processing calculates some statistics from the wind product and writes them to an ASCII file with the same name as the BUFR output file and extension mon The monitoring parameters are listed in table 4 23 They are calculated separately for five different regions WVC ranges of the swath Note that the monitoring is invoked only if the mon command line option is set Parameter Description obse
76. es to their probability Date and time General purpose Table 4 2 genscat module classes 4 1 3 Data Structure Along track the OSCAT swath is divided into rows Within a row across track the OSCAT orbit is divided into cells also called Wind Vector Cells WVCs or nodes This division in rows and cells forms the basis of the main data structures within the OWDP 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 OSCAT data files corresponds to the mapping of a BUFR message or HDF5 datasets to one or more 29 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 instances of the row_type and 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 beam_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 four instances of the beam_type corresponding to the inner fore outer fore inner aft and outer aft beams A cell may also contain an a
77. eserved 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 see 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_mes
78. ete and it may be necessary for some platforms to download specific versions of the HDF5 software libraries from http www hdfgroup org and to place them under the correct name in genscat support hdf5 hdfgroup See the file Readme txt in this directory for more information 2 3 6 Compilation and linking Compilation and linking of OWDP 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 Goto directory genscat and type make 3 Go to directory owdp and type make to produce the executable owdp in directory owdp 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 InstallOWDP 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 owdp directories is perform
79. 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 land fraction calculation in OWDP 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 averag
80. h DeallocBatchRows DeallocBatchCells DeallocBatchAmbis ExitAmbremMethod ExitTwodvarModule TDV_Exit Figure A 8 Calling tree for routine remove_ambiguities first level The full name of the 12 routine is AllocRowsAndCellsAndInitBatch 78 OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 Reference Guide Date December 2011 NWP SAF gt postprocess GetElapsedSystemTime monitoring speeddir_to_u speeddir_to_v get_lun free_lun get_lun free_lun get_lun free_lun Figure A 9 Calling tree for routine postprocess first level gt write_bufr_file GetElapsedSystemTime init_bufr_processing set_BUFR_file_attributes open_BUFR_file gt InitAndSetNrOfSubsets row_to_bufr_data_gen Bufrint2Real set_s0_quality set_s0_mode set_s0_surface set_wvc row_to_bufr_data_noaa quality_gen Bufrint2Real set_wvc_quality_noaa set_sO_ quality set_s0_mode set_s0_surface save_BUFR_message gt close_BUFR_fille gt Figure A 10 Calling tree for routine write_bufr_file first level 79 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and yrs 1001 Reference Guide Date December 2011 gt init_cell Figure A 11 Calling tree for routine init_cell second level gt test_cell test_beam Figure A 12 Calling tree for routine test_cell second level gt print_cell Figu
81. he 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 000387 but later versions or earlier but not earlier than 000240 can be used However OWDP is not tested with later versions 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 6 2 3 4 Installing the GRIB API library OWDP 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 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 lib 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 ma
82. i 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 69 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 References e Belmonte Rivas M and Stoffelen A 2011 New Bayesian algorithm for sea ice detection with QuikSCAT IEEE Transactions on Geoscience and Remote Sensing I 49 6 1894 1901 doi 10 1109 TGRS 2010 2101608 e Dragosavac M 1994 BUFR User Guide and Reference Manual ECMWF Available on http www ecmwf int e Giering R 1997 Tangent linear and Adjoint Model Compiler Users manual Max Planck Institut fuer Meteorologie e Leidner M Hoffman R and Augenbaum J 2000 SeaWinds scatterometer real time BUFR geophysical data product version 2 3 0 NOAA NESDIS June 2000 available on ftp metroweb nesdis noaa gov seawinds bufr_v2 3 0 ps gZ e Liu D C and Nocedal J 1989 On the limited memory BFGS method for large scale optimization methods Mathematical Programming 45 pp 503 528 e Padia K 2010 Oceansat 2 Scatterometer algorithms for sigma 0 processing and products format Version 1 1 April 2010 ISRO 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 St
83. ing 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 error_speed real Uncertainty in wind speed not used in OWDP error_dir real Uncertainty in wind direction not used in OWDP prob real Probability of wind vector solution conedistance real Distance of solution to the GMF Table 4 5 Ambiguity data structure Beam data Every WVC contains four beams The information of every beam is stored in the data type beam_type The attributes are listed in table 4 6 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 sum_weights real Sum of weights used in averaging of level 2a slices num integer Presence of backscatter data 0 or 1 identifier integer 1 inner fore 2 outer fore 3 inner aft 4 outer aft k_polar integer Beam polarisation 0 HH pol 1 VV pol lat real Beam latitude lon real Beam longitude atten_val real Two way nadir atmospheric attenuation azimuth real Radar look angle degrees counted clockwise from the North incidence real
84. ion To establish the MLE function 1 the radar cross section according to the GMF E 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 GMF at Ku band for HH and VV polarization needed for OSCAT is not 45 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and asin 1001 Reference Guide Date December 2011 known in analytical form It is only available in the form of lookup tables in directory OWDP data The value for a is obtained from interpolation of this table The interpolation is done via symbolic routine INTERPOLATE which is set to interpolateld interpolate2d interpolate2dv or interpolate3d depending on the type of interpolation needed 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 OSCAT the radar look angle antenna angle or simply azimuth equals 0 if the antenna is orientated towards the North oceanographic convention The radar look angle increases clockwise Therefore the antenna angle needs does not need a correction Meteorological Oceanographic
85. ion 4 2 4 for the interface with the BUFR routine library Table 4 20 provides an overview of the different routines and their calls in this module Call read_bufr_file read_bufr_file read_bufr_file write_bufr_file OWDP write_bufr_file write_bufr_file Routine bufr_to_row_data_gen bufr_to_row_data_noaa init_bufr_processing Description KNMI format BUFR message into one row_type NOAA format BUFR message into one row_type Initialise module read_bufr_file row_to_bufr_data_gen row_to_bufr_data_noaa Read a complete BUFR file into row_types OWDP row_type into KNMI format BUFR message OWDP row_type into NOAA format BUFR message 39 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Routine Call Description write_bufr_file OWDP Write all row_types into a complete BUFR file Table 4 20 Routines in module owdp_bufr Note that the OSCAT BUFR messages always contain exactly one data row 4 3 3 Module owdp_hdf5 The module owdp_hdf3 maps the datasets in a HDFS5 file on the OWDP data structure It is capable to read both level 2a and level 2b files from ISRO For level 2a only the backscatter information in the OWDP data structure will be filled for level 2b only the wind information in the OWDP data structure will be filled Table 4 21 provides an overview of the different routines and their calls in this module Several routines from th
86. ion dB 112 021106 Kp Variance Coefficient Alpha Numeric 113 021107 Kp Variance Coefficient Beta Numeric 114 021114 Kp Variance Coefficient Gamma dB 115 021115 SeaWinds Sigma 0 Quality Flag Table 116 021116 SeaWinds Sigma 0 Mode Flag Table 117 008018 SeaWinds Land Ice Surface Type Flag Table 118 021117 Sigma 0 Variance Quality Control Numeric Table C 1 List of data descriptors Note that descriptor numbers 93 96 can be repeated 1 to 144 times depending on the value of the Delayed Descriptor Replication Factor descriptor number 92 Number Descriptor Parameter Unit 1 001007 Satellite Identifier Code Table 2 001012 Direction Of Motion Of Moving Observing Platform Degree True 3 002048 Satellite Sensor indicator Code Table 4 021119 Wind Scatterometer Geophysical Model Function Code Table 5 025060 Software Identification Numeric 6 002026 Cross Track Resolution m 7 002027 Along Track Resolution m 8 005040 Orbit Number Numeric 9 004001 Year Year 10 004002 Month Month 11 004003 Day Day 12 004004 Hour Hour 13 004005 Minute Minute 14 004006 Second Second 15 005002 Latitude Coarse Accuracy Degree 16 006002 Longitude Coarse Accuracy Degree 17 008025 Time Difference Qualifier Code Table 18 004006 Time to Edge Second 19 005034 Along Track Row Number Numeric 20 006034 Cross Track Cell Number Numeric 21 021103 Total Number of Sigma 0 Measurements Numeric 22 021120 Probability of Rain Numeric 23 021121 SeaWinds NOF
87. itialise NWP stress parameters structure init_process_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_icemodel Print ice model structure print_nwp_stress_param Print NWP stress parameters structure print_process_flag Print process flag structure print_s0_mode Print 0 mode flag structure print_s0_quality Print o quality flag structure print_s0_surface Print o surface flag structure print_time Print time structure print_wind Print wind structure print_wvc_quality Print quality flag structure set_s0_mode Convert logical a mode flag to integer set sO_quality Convert logical a quality flag to integer set_s0_surface Convert logical o surface flag to integer set_wvc_quality_gen Convert logical WVC quality to integer generic set_wvc_quality_noaa Convert logical WVC quality to integer NOAA 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 19 Routines in module owdp_data 4 3 2 Module owdp_bufr The module owdp_bufr maps the OWDP data structure on BUFR messages and vice versa A list of the BUFR data descriptors can be found in appendix C The owdp_bufr module uses the genscat module BufrMod see subsect
88. ke system and it is automatically invoked when compiling genscat The current version is tested with GRIB API version 1 9 9 but later versions or earlier but not earlier than 1 9 0 can be used However OWDP is not tested with later versions 2 3 5 Installing the HDF5 library The HDFS software library from the HDF Group http www hdfgroup org is used by OWDP for reading and decoding HDF5 input files See Appendix E for the copyright statement and the terms of use of this software Binary libraries compiled for different Linux and Unix platforms are delivered with OWDP in directory genscat support hdf5 hdfgroup The Makefile in this directory tries to determine the operating system and creates a symbolic link from one of the binary libraries to a file called l1ibhdf5 a For example directory genscat support hdf5 hdfgroup contains a library called 1ibhdf5_1in_i386 a which is compiled for the 32 bits Linux platform The Makefile will link this file to libhd 5 a which in its turn will be linked when compiling OWDP The same mechanism is used for some of the include files h in this directory which are also platform specific This directory also contains the binary SZIP and ZLIB libraries that are used in conjunction with the HDES library 13 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 Note that the collection of delivered libraries is by no means compl
89. l Number of Sigma 0 Measurements Numeric 27 021120 Probability of Rain Numeric 28 021121 SeaWinds NOF Rain Index Numeric 29 013055 Intensity of Precipitation kg m s 30 021122 Attenuation Correction of Sigma 0 from Tb dB 31 011012 Wind Speed At 10 m m s 32 011052 Formal Uncertainty in Wind Speed m s 33 011011 Wind Direction At 10 m Degree True 34 011053 Formal Uncertainty in Wind Direction Degree True 35 021104 Likelihood Computed For Solution Numeric 36 011012 Wind Speed At 10 m m s 37 011052 Formal Uncertainty in Wind Speed m s 38 011011 Wind Direction At 10 m Degree True 39 011053 Formal Uncertainty in Wind Direction Degree True 97 DocID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 Number Descriptor Parameter Unit 40 021104 Likelihood Computed For Solution Numeric 41 011012 Wind Speed At 10 m m s 42 011052 Formal Uncertainty in Wind Speed m s 43 011011 Wind Direction At 10 m Degree True 44 011053 Formal Uncertainty in Wind Direction Degree True 45 021104 Likelihood Computed For Solution Numeric 46 011012 Wind Speed At 10 m m s 47 011052 Formal Uncertainty in Wind Speed m s 48 011011 Wind Direction At 10 m Degree True 49 011053 Formal Uncertainty in Wind Direction Degree True 50 021104 Likelihood Computed For Solution Numeric 51 002104 Antenna Polarisation Code Table 52 008022 Total Number w r t Accumulation or Average Numeric 53 01206
90. le is only used in the owdp_hdf5 module see subsection 4 3 3 4 2 7 Support modules Subdirectory genscat support contains more support modules besides Bufrmod gribio_module and HDF5Mod 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 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 OWDP only uses routines GetElapsedSystemTime for calculating the running time of the various processing steps and DayJulian 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 o
91. les are above a specified threshold Onset of the flag indicates that the input should be rejected for ingestion in the NWP data assimilation system Details on the monitoring flag can be found in the NWP SAF document de Vries Stoffelen and Beysens 2005 3 6 Details of performance Table 3 2 gives the approximate times needed for processing one level 2a 50 km orbit file under various options on a workstation with a 3 00 GHz Intel Core TM 2 Duo CPU processor under Linux using the Portland Fortran compiler Cell spacing m MSS Inversion AR BUFR IO GRIB IO Total seconds seconds seconds seconds seconds 50000 No 11 5 1 0 4 0 5 15 50000 Yes 13 4 0 4 0 5 19 Table 3 2 Approximate times needed by OWDP to process example HDFS files using various options As can be seen from table 3 2 the use of MSS results in slightly larger processing times needed for 23 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and sion 1001 Reference Guide Date December 2011 inversion in much larger processing times needed for AR and a modest overall increase in processing time 25 The choice of platform compiler and compiler settings will generate a large variation in the processing times 26 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Chapter 4 Program Design In this chapter the design of the OWDP program is described in detail Readers to
92. ll by cell basis The attributes are listed in table 4 8 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_11b integer Software identification of level 1 processor satellite_id integer Satellite identifier sat_instruments integer Satellite instrument identifier sat_instr_short integer Instrument short name code table 02048 gmf id integer Identifier of GMF used code table 21119 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 time_to_edge integer Time to beginning or end of data file s time_diff_qual integer Time difference qualifier code table 08025 pixel_size_hor real Distance between WVCs meters orbit_nr integer Orbit number row_nr integer Along track row number node_nr integer Across track cell number s0_in_cell integer Number of beams containing data in cell rain_prob real Probability of rain not used in OWDP rain_nof real Rain normalised objective function not used in OWDP rain_rate real Rain rate not used in OWDP rain_attenuation real
93. lt Note that these modes are always used in combination with the lt input file gt option mononly Write the monitoring file without any processing properties Write some properties of the last row of the input file The acquisition date and time 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 owdp 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 owdp 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 a name which is derived from the input file name e Ifthe input file name contains the substring L2A this part will be replaced by L2B e Ifthe input file name contains the substring h5 this part will be replaced by bufr e The extension bufr is added to the output file name when it is not yet present e If the above substitutions result in identical input and output file names the extension is added to the output file name Example the input file name S112A2011311_11243_11244_2 h5 results in an output file name 1L2B2011311_ 11243 11244 2 bufr 2 5 Scripts Directory owdp execs contains a Bourne shell script owdp_run for running owdp with
94. ma0 invert_one_wvc invert_one_wvc see B 1 OWDP invert_one_wvc OWDP not used OWDP OWDP invert_one_wvc 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 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 not used normalise_conedist_ers_ascat calc_kp_ers_ascat not used normalise_conedist_prescat_mode not used not used check_wind_solutions_ers_ascat OWDP Table 5 2 Routines of module post_invers
95. module owdp_grib reads in ECMWF GRIB files and collocates the model data with the scatterometer measurements The owdp_grib module uses the genscat module gribio_module see subsection 4 2 5 for the interface with the GRIB routine library Table 4 24 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 41 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Routine Call Description get grib data OWDP Get land mask ice mask and background winds using GRIB data init_grib_processing get grib data Initialise module Table 4 24 Routines in module owdp_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 as well as the ice flags in the sO_surface for each beam Note that the sea surface temperature screening step is omitted if the ice screening is used see section 4 3 7 Land 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 WV
96. n 1001 Reference Guide Date December 2011 control the size the log several modules contain parameters for the level of verbosity The verbosity of the OWDP program may be controlled by the verbosity command line option verbosity In general there are three levels of verbosity specified lt 1l be as quiet as possible 0 only report top level processing information 21 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 owdp_bufr BufrVerbosity owdp_hdf5 hdf3_verbosity owdp_grib GribVerbosity 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 for probability computations The modules are located in subdirectory genscat inversion Details of this module are described in Chapter 5 In the OWDP program the inversion module is only used in the owdp_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
97. n quality flag 53 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Mamual and yn 1001 Reference Guide Date December 2011 6 4 3 Reformulation and transformation The minimization problem to find the analysis surface wind field the 2D Variational Data Assimilation problem may be formulated as min J JT S ap J VY 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 v w vel B I vyl 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 To
98. n 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 tables These tables are therefore essential to decode and encode the data BUFR tables are issued by the various meteorological centres The largest part of the data 22 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 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 output of the OWDP program in the NOAA QuikSCAT BUFR product format and the KNMI BUFR format with generic wind section 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 OWDP program BUFR interface see Chapter 8 3 5 2 Backscatter slice averaging The HDF
99. ng o kp 20 1048576 Any beam noise content above threshold monflag 12 4096 19 524288 Product monitoring not used monvalue 11 2048 18 262144 Product monitoring flag knmi_qc 10 1024 17 131072 KNMI quality control fails var_qc 9 512 16 65536 Variational quality control fails land 8 256 15 32768 Some portion of wind vector cell is over land ice 7 128 14 16384 Some portion of wind vector cell is over ice inversion 6 64 13 8192 Wind inversion not successful large 5 32 12 4096 Reported wind speed is greater than 30 m s small 4 16 11 2048 Reported wind speed is less than or equal to 3 m s rain_fail 3 8 1 1024 Rain flag not calculated rain_detect 2 4 512 Rain detected 0 9 no_background 8 256 No meteorological background used redundant i 128 Data are redundant gmf distance 6 64 Distance to GMF too large four beam 1 2 5 32 Oneofthe four beams is missing reserved 13 8192 4 16 Reserved Table 4 17 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 18 lists the attributes of the process_flag_type The process flag is only available internally in OWDP The routine print_process_flag may be used to print the bit values of
100. ng points 15 NWP SAF OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 Reference Guide Date December 2011 may be helpful for Cygwin users e The GNU g95 compiler comes standard with Cygwin version 1 5 25 11 and later so it is always possible to install OWDP using g95 e Cygwin has its own path naming convention for example C owdp under Windows becomes cygdrive c owdp under Cygwin e Don t forget to run the dos2unix command on scripts edited under Windows otherwise Cygwin won t recognize the file as a script 2 4 Command line options The OWDP program is started from directory owdp execs with the command owdp options modes f lt HDF5 BUFR 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 an HDF5 or BUFR input file with name input file nwpfl lt file gt OWDP detects if the input file is in BUFR format If not it attempts to read the input as HDF5 file The input file should contain 50 or 25 km level 2a or level 2b data Example owdp f 11L2A2011311_11243_11244_2 h5 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 HDFS files must be processed one by
101. nmi nl scatterometer publications e Vogelzang J Stoffelen A Verhoef A de Vries J and Bonekamp H 2009 Validation of two dimensional variational ambiguity removal on SeaWinds scatterometer data J Atm Oceanic Technol 7 2009 26 1229 1245 doi 10 1175 2008JTECHA1232 1 e Vogelzang J and Stoffelen A 2011 Wind Bias Correction Guide Report NWPSAF UKMO UK 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 Wentz F J 1996 Climatology of 14 GHz Atmospheric Attenuation final delivery Remote Sensing Systems May 20 1996 71 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and yrs 1001 Reference Guide Date December 2011 Appendix A Calling tree for OWDP The figures in this appendix show the calling tree for the OWDP program Routines in white boxes are part of the OWDP 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 indicates that this branch will be continued in a following figure largc_genscat getarg_genscat write_usage r
102. ocess Module name Tasks Comments owdp_data Definition of data structures owdp_bufr BUFR file handling Interface to genscat support bufr owdp_hdf5 HDFS file handling Interface to genscat support hdf5 owdp_prepost Quality control Usability of input data is determined Atmospheric attenuation Backscatter calibration Post processing Setting of flags Monitoring Clean up Deallocation of used memory owdp_grib GRIB file handling Interface to genscat support grib Collocation of GRIB data NWP data are interpolated w r t time and location owdp inversion Inversion Interface to genscat inversion 28 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Module name Tasks Comments owdp_ambrem Ambiguity Removal Interface to genscat ambrem owdp_icemodel Ice screening Interface to genscat icemodel Table 4 1 OWDP 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 owdp_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 1 e groups of modules used in the OWDP program are listed in table 4 2 The gen
103. of the batch data structure Descriptions of the attributes of the individual batch data components are given in table 6 3 48 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Veian 1 0 01 Reference Guide Date December 2011 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 49 Doc ID Version Date NWPSAF KN UD 006 1 0 01 December 2011 NWP SAF OWDP 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 Ty
104. offelen 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 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 70 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 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 Talagrand O 1991 The use of adjoint equations in numerical modeling of the atmospheric circulation In Automatic Differentiation of Algorithms Theory Implementation and Application A Griewank and G Corliess Eds pp 169 180 Philadelphia Penn SIAM e Verhoef A Vogelzang J Verspeek J and Stoffelen A 2011 OWDP Test Report Report NWPSAF KN TV UKMO UK e Vogelzang J 2007 Two dimensional variational ambiguity removal 2DVAR Report NWPSAF KN TR 004 UKMO UK Available on http www k
105. olution 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 OWDP program includes the Multiple Solution Scheme MSS see Portabella and Stoffelen 2001 44 NWP SAF OWDP User Manual and Reference Guide Doc ID Version Date 1 0 01 NWPSAF KN UD 006 December 2011 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 OWDP INTERPOLATE generic fill_wind_quality_code invert_one_wvc interpolateld calc_sigma0 save_inv_input not used interpolated2d calc_sigma0 read_inv_input not 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_sig
106. ontains 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 OSCAT data are needed to entirely fill the ice map with data and give meaningful ice model output Because OWDP handles only one BUFR file at a time a script 5l Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 is needed that calls OWDP several times After each OWDP run a binary restart file is written to disk containing the information of an icemap latestIceMapN rst for the North Pole and latestIceMapS rst for the South Pole With the next call of owdp these restart files are read in again Environment variable S RESTARTDIR 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 quality of the ice algorithm the use_sst logical must be turned on Processing 11b input with the use of NWP data and SST data can be done with the following command line options owdp f lt bufr file gt nwpfl lt gribfilelist gt icemodel Reprocessing of level 2 input with only running the ice model on top of it can be done with the following command line options owdp f lt bufr file gt icemodel noinv noamb handl
107. ormation 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 attributes list_of GRIB_msgs grib message data array List of messages in file Table 9 4 Attributes of the list_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_ap
108. ound 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 NWP background wind vector WVC quality flag and information on the scatterometer beams including o and K data The BUFR data descriptors of both available data formats are listed in Appendix C 3 3 Input specification Input of OWDP is the OSCAT level 2a L2A HDF5 Data Product These products are created by 21 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 ISRO see Padia 2010 The first operational ISRO L2A product is denoted version 1 3 OWDP has the ability to process earlier experimental and pre operational versions as well Alternatively the OSCAT level 2b HDF5 Wind Data Product can be read but in this case wind processing is not possible since the level 2b product does not contain o data It is also possible to reprocess level 2 OSCAT in NOAA BUFR format or KNMI BUFR format containing generic wind section and treat them as if they are input data Apart from the scatterometer data GRIB files containing NWP output with global coverage are necessary for the wind processing At least three wind forecasts wi
109. ovMat Calculate yw StrucFuncChi SetCovMat Calculate y Table 6 13 Routines of module StrucFunc Routine nitStrucFunc sets the structure function parameters to a default 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 1bfgs_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 LBFGS 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 thi
110. ovides an overview of the routines in module gribio_module The most important ones are described below Routine Call Description init_GRIB_module OWDP Initialization routine dealloc_all_GRIB_messages OWDP Clear all GRIB info from memory and close GRIB files set_GRIB filelist OWDP Open all necessary GRIB files get from_GRIB filelist OWDP Retrieve GRIB data for a given lat and lon get colloc_from_GRIB_filelist inquire GRIB filelist OWDP Inquiry of GRIB file list 66 NWP SAF OWDP User Manual and Reference Guide Doc ID Version Date NWPSAF KN UD 006 1 0 01 December 2011 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 OWDP get field_from_GRIB_file get from_GRIB file get_from_GRIB filelist inquire _GRIB filelist get 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
111. pe Description selection Integer Index of selected ambiguity uana Real u component of analysis wind vana Real v component of analysis wind f Real Contribution 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 AllocAndInitBatchCell Processor AllocRowsAndCellsAndInitB
112. pening and closing free logical units in Fortran OWDP uses only routines get lun and free lun for opening and closing of a logical unit respectively Subdirectory num contains module numerics for handling missing values for instance in the BUFR library This module is needed by module DateTimeMod and is used in the test program test_modules Subdirectory sort finally contains module SortMod for sorting the wind vector solutions according to their probability This module is needed by modules inversion and post_inversion 32 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 4 3 Module design for process layer The process layer consists of the modules owdp data owdp_bufr owdp_hdf5 owdp_prepost owdp_grib owdp_inversion owdp_icemodel and owdp_ambrem The routines present in these modules are described in the next sections 4 3 1 Module owdp_data The module owdp_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 document
113. ported in Verhoef et al 2011 1 4 User Manual and Reference Guide This document is intended as the complete reference book for OWDP Chapter 2 is the user manual UM for the OWDP program This chapter provides the basic information for installing compiling and running OWDP Chapter 3 contains the Product Specification PS of the OWDP program Reading the UM and the PS should provide sufficient information to the user who wants to apply the OWDP 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 OWDP 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 scatterometer genscat layer and are described in Chapter 5 to Chapter 9 The appendices of this document contain a complete calling tree of the OWDP program up to and including the genscat layer The appendices also contain a list of 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 owdp src files e g owdp F90
114. rabolic_winddir_search get_parabolic_minimum GetSortIndex SortWithIndex calc_sign_MLE calc_sigma0 gt fill_wind_quality_code gt Figure B1 1 Calling tree for inversion routine invert_one_wvc gt 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 83 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 interpolate 1d interpolate2d interpolate2dv or interpolate3d There are several equivalent routines to calculate the CMOD backscatter like calc_sigma0_cmod5 calc_sigma0_cmod3_5 calc_sigma0_cmod5_n 84 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and yrs 1001 Reference Guide Date December 2011 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 gt before a routine name indicates that this part of
115. re A 13 Calling tree for routine print_cell second level gt calclceCoord calclcelineParms Figure A 14 Calling tree for routine calclceCoord second level OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 updatelcePixel ExpandDateTime getClass printlcePixel Figure A 15 Calling tree for routine updatelcePixel second level 81 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and yrs 1001 Reference Guide Date December 2011 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 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 82 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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_sO find_minimum_cone_dist gt my_min my_average my_max get_indices_lowest_local_minimum my_index_max print_message do_pa
116. riational principles This is a very common method originating from the broad discipline of Data Assimilation The optimal surface wind vector field is called 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 a 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 wi
117. rray 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 check the validity of the data and to check the data quality In the OWDP 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 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 30 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and 4 kio
118. rvation 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 NS rms_diff dir RMS over N5 difference between observed and model wind directions 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 23 Parameters in monitoring output 4 3 5 Module owdp_grib The
119. s 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 output 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 55 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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
120. scat 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 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 discremination Support BUFR support BufrMod based on ECMWF library HDFS support Reading of HDF S 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 ambiguiti
121. sed in OWDP is based on probabilistic distances to ocean wind and sea ice Geophysical Model Functions Backscatter points closer to the wind GMF have a higher probability of being open water whereas backscatter points closer to the ice GMF have a higher probability of being ice A more detailed description of this Bayesian statistics method and ice model is given in Belmonte et al 2011 The icemodel option in OWDP basically fills the fields Ice Probability and Ice Age both present in the KNMI BUFR format with generic wind section 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 Oceansat 2 satellite passes over the pole region the corresponding ice map is updated with the new OSCAT 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 yyyymmddhhnms s t ppm c
122. sion 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 Section 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 pr
123. sor Microwave Imager SST Sea Surface Temperature WVC Wind Vector Cell also called node or cell Table D 1 List of acronyms 102 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and yrs 1001 Reference Guide Date December 2011 Appendix E HDFS library copyright statement This is the contents of the file called COPYING that is provided with the HDF Group software library and utilities The text is also on http www hdfgroup org HDF5 doc Copyright html Copyright Notice and License Terms for HDF5 Hierarchical Data Format 5 Software Library and Utilities HDF5 Hierarchical Data Format 5 Software Library and Utilities Copyright 2006 2009 by The HDF Group CSA HDF5 Hierarchical Data Format 5 Software Library and Utilities Copyright 1998 2006 by the Board of Trustees of the University of Illinois All rights reserved Redistribution and use in source and binary forms with or without modification are permitted for any purpose including commercial purposes provided that the following conditions are met 1 Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer 2 Redistributions in binary form must reproduce the above copyright notice this list of and or materials provided with the distribution conditions and the following disclaimer in the documentation 3 In addition redistributions of modified
124. ssceeceesaeeecsnseececseeeecessaececseaaeeecsaeecsesaeeecsesaesecseeeeenes 18 2 7 DOCUMENTATION otrora IA ante Waseda ene ae eae ties Gea ets 20 CHAPTER 3 OWDP PRODUCT SPECIFICATION ccssscccssssscesssscccssssccccssscccesssscccssssccesssscceses 21 3 1 PURPOSE OF PROGRAM OWDD ccssccecesssecessesceceeaececsesaececseaceceesaececsesaeeeceseeeesesaeeecsesaeessneeeenes 21 3 2 OUTPUT SPECIFICATION ccccoiiocccdooiacdadc Wi eeceten n ieii ir ae iE e dee E E Ea iah 21 3 3 INPUT SPECIFICATION ii a a ia ines EEEE EEEN 21 3 4 SYSTEM REQUIREMENTS ii Ai iake 22 35 DETAILS OF FUNCTIONALITY eu sora rea depois Geb benedeadie aeie s oa Dietas 22 SOL BUERLO GRA coding ie ee fesse A sits ic ses cat sepa Eaa RE don da aia 22 3 5 2 Backscatter slice AVeraging eiieeii a a e a eE aieiai 23 3 5 3 Atmospheric attenuation ccccccccccccccecceseescerecsessecseseecuseescesesseeseeseeseesesiesecnseeseeseeseeesieeeeeneeetee 24 IIA Quality CONO A A a acia 24 IN ANVERSO AR AER A EE E A EEC A 24 3 536 gt AMDIBUUIV Removal lt A A E a ay ae gan ee eye 25 II MORON Lo MMe heii dD lt aie EL aida id 25 3 6 DETAILS OF PERFORMANCE cuinciocoiia idad cias ida ds 25 CHAPTER 4 PROGRAM DESIGN icc iscsesscscssccsssssscsssesesceseseesosecsc sssessossesdsaseeesaesessencsssesiscsesscosesseseoesie 27 4 1 TOP LEVEE DESTINA eared aed aed ae 27 4 1 1 M in program A AI A Aaa ee gu thn Ted Ta SAES 27 4 1 2 Layered model Structure cccccccesccscsescssssscesesseeecs
125. ssscccessecsccssseccessscsccesss 57 7 1 BACKGROUND cocida tdt 57 Td ROUTINES sereni e a a A dl 58 7 3 DATA STRUCTURES 0 aia asc 58 7 4 PARAMETERS e E tes 59 CHAPTER 8 MODULE BUFRMOD ccccssccssssscscssssscccssssccsssscccessssccscssccccsssscccessscccesscescssssccsesssseceses 61 8 1 BACKGROUND 2ccsstiecets 2 22058 sects at sed ed cones loved Bh eosin sess 61 8 2 ROUTINES 2 esas eee cases ioe Hes ee ee et 61 8 3 IDATA STRUCTURES EEPO ETE ESET ES E E E ATES 63 8 4 LIBRARIES o E E E E E E E E Sao es A 64 8 5 BUFR TABLE ROUTINES scccssssceceessececseeececsseeeceeaececseseececseeeecsesaeeecseaaeeeceeeeeseaeeeesesaeeeeseeeeenes 65 8 6 CENTRE SPECIFIC MODULES cui e ada dies 65 CHAPTER 9 MODULE GRIBIO_MODULE scccssssccsssssscsssscccessssccsssssccssssscccessscccssssscsessscceesssscesses 66 9 1 BACKGROUND A ee A Bee A 66 9 2 ROUTINES dan lod 66 9 3 DATA STRUCTURES votada tel dl e dotado del dalt edades dae 68 9 4 LIBRARIES coi a die iden i i E E da een 69 REFERENCES nrinn naaie e teaa tar EAE L EEE EVE Ee AEE E E EAER 70 APPENDIX A CALLING TREE FOR OWDP eessesecssececssecssosecsscocecssecesssecssocseessoceessecessecssoseessecee 72 NWP SAF OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 APPENDIX B1 APPENDIX B2 APPENDIX B3 APPENDIX B4 APPENDIX B5 APPENDIX B6 APPENDIX C APPENDIX D APPENDIX E Reference Guide Date December 2011 CALLING TREE FOR INVERSION ROUTINES wessscc
126. ssssssssssssssssssscsssssnscsecessssnscces 82 CALLING TREE FOR AR ROUTINES csssssssssssssssssccssssnsssssssssnscecssssssnscessssssnecces 85 CALLING TREE FOR BUFR ROUTINES ssssscsssssssssssssssssssscsssssnsescsssssnscsesssssnscces 89 CALLING TREE FOR GRIB ROUTINES ssssssssssssssscsssssssescsssssnscscsssssnscsecsesssnscces 91 CALLING TREE FOR HDF5 ROUTINES ssssscssssssssscsssssssesscsssssnscscsssssnscsesesssnscces 93 CALLING TREE FOR ICE MODEL ROUTINES wssssssssssssssessssssessssssseessssseesssase 96 BUFR DATA DESCRIPTORS osssssscsssssssssscsssssssssscsssnscsescsssnscseccsssnscsscssssnessecssssnsssses 97 ACRONYM S Jada 102 HDF5 LIBRARY COPYRIGHT STATEMENT ssssssssssssssssssssssssessssssesssssseesssnse 103 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 activities aiming at enhancing the modularity readability and portability of the processing code The Indian Oceansat 2 satellite carries a Ku band rotating pencil beam scatterometer and was launched in September 2009
127. tal 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 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 54 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 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 SetC
128. template or the KNMI BUFR template with generic wind section Currently the level 2a data from the Indian Space Research Organisation ISRO are only available on 50 km grid spacing but in principle it is possible to convert OSCAT level 1b data into a 25 km level 2a product and process this on 25 km using OWDP Apart from the OSCAT input data OWDP 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 OWDP OWDP 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 OWDP may be run on every modern Unix or Linux machine In principle OWDP can also be run on a Windows machine if a Unix emulator like Cygwin is installed 13 Testing OWDP Modules are tested by test programs and test routines Many test routines or test support routines Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 are part of the modules themselves Test programs can be compiled separately For the OWDP program the description of the test programs and the results of the testing are re
129. th 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 which OWDP 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 OWDP requires about 150 200 MB disk space when installed and compiled Platform Fortran compiler C compiler Suse workstation or Portland pgf90 GNU gcc Fedora workstation 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 OWDP has been tested OWDP 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 and GRIB libraries are properly installed For Windows a Unix emulator like Cygwin 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 i
130. th the 2DVAR scheme is set by module Ambrem2DVAR Table 6 6 lists its routines that serve the interface with TwoDvar 51 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 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 ExitTwodvarModule 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
131. the correct environment variables The script can be invoked with all valid command line options for owdp 2 6 Test data and test programs Directory owdp tests contains one HDFS file for testing the OWDP executable File s112A2011311_11243_11244_2 h5 gz contains gzipped OSCAT level 2a data from 7 November 2011 13 51 to 14 03 UTC with 50 km cell spacing as obtained from ISRO 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 OWDP using the files in the owdp tests directory To do this first create a small file containing a list of NWP files 18 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 ls 1 ECMWF_ gt nwpflist Then gunzip the HDF5 file gunzip c 1L2A2011311_11243_11244_2 h5 gz gt 1L2A2011311_11243_11244_2 h5 Then run OWDP execs owdp_run f S112A2011311_11243_11244_2 h5 nwpfl nwpflist mss mon calval The result should be an OSCAT level 2 file in BUFR format called S1L2B2011311_11243_11244_2 bufr Figure 2 3 shows the global coverage of the test run The colours indicate the magnitude of the wind speed as indicated by the legend 160 w 140 W 120 10 w ww so w aow 20 w or rE 40 E Ore 80 E 100 E 120 E 140 E 160 E m s EI RENA ERAT SERS f nl PA Sal aH 1 i
132. tio negative 13 8192 o is negative range 12 4096 0 is outside acceptable range pulse 11 2048 Pulse quality not acceptable 36 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 Attribute Bit 25 Description convergence 10 1024 Location algorithm does not converge freg_shift 9 512 Frequency shift beyond range temperature 8 256 Spacecraft temperature beyond range attitude 7 128 No applicable attitude records ephemeris 6 64 Interpolated ephemeris data Table 4 14 Sigma0 quality flag bits Fortran Sigma0 mode flag The sO mode type data type contains the flag indicating the properties of the a measurement Each of the four beams in a WVC contains an instance of this flag The attributes are listed in table 4 15 The function get_s0_mode converts an integer value BUFR input to the logical flag structure The function set_s0_mode converts a logical flag to an integer value Attribute Bit 24 Description missing Flag not set all bits on outer 13 8192 0 is of outer beam aft 12 4096 0 is aft of satellite Table 4 15 Sigma0 mode flag bits Fortran Sigma0 surface flag The s0_ surface type data type contains the flag indicating land or ice presence in the o measurement Each of the four beams in a WVC contains an instance of this flag The attributes are listed in table 4 16 The function get s0_surface converts an integer value BUFR inp
133. ty of California The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California and shall not be used for advertising or product endorsement purposes 104
134. und 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 for the WVC a second naive Ambiguity Removal scheme is at hand the Background Closest BC scheme The selected wind vector is just the minimiser 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 The implementation of the 2DVAR scheme in OWDP is described in sections 6 4 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 47 OWDP User Manual and Doc ID NWPSAF KN UD 006 Version 1 0 01 Reference Guide Date December 2011 NWP SAF 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 interfa
135. update timeMapPrev DateTime Date time of previous ice map update xy IcePixel nPixels nLines Pointer to the ice map contents Table 7 3 Attributes for the IceMapType data type 7 4 Parameters There are several parameters involved that control the Bayesian statistics They have sensible default values but most of them are made public so that their value can be overridden in the main program Parameter Description Class_no_data Class no data Class_sea Class sea wind Class_ice Class ice Class_sea_or_ice Class sea or ice indecisive Class_no_sea_no_ice Class unknown outlier SubClass_a2 SubClass sea SubClass_b1 SubClass sea or ice weight lt weightSTLimit SubClass_b2 SubClass probably ice SD a gt aSdLimit SubClass_b3 SubClass ice SubClass_d SubClass unknown outlier 59 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Parameter Description SubClass_no_data SubClass no data plceGivenXlimit Lower limit of p ice X for classifying a pixel as ice sstLowLimit Lower limit for sea surface temp Below this limit pixels are classified as ice sstHighLimit Upper limit for sea surface temp Above this limit pixels are classified as sea Table 7 6 Parameters in the Bayesian statistics 60 Doc ID NWPSAF KN UD 006 NWP SAF OWDP User Manual and Version 1 0 01 Reference Guide Date December 2011 Chapter 8 Module BufrMod
136. ut to the logical flag structure The function set_s0_surface converts a logical flag to an integer value Attribute Bit 2 Description missing Flag not set all bits on land 15 32768 Landis present ice 14 16384 Ice is present ice_map 5 32 Ice map data not available atten_map 4 16 Attenuation map data not available Table 4 16 Sigma0 surface flag bits Fortran Wind Vector Cell quality flag Every WVC contains a flag for its quality Therefore the cel _type contains an instance of the wvc_quality_type Table 4 17 gives an overview of its attributes The implementation of this flag is different in the NOAA BUFR format and the KNMI BUFR format with generic wind section The functions get wvc_quality_noaa and get _wvc_quality_gen interpret an integer flag BUFR input to an instance of wve quality type The functions get wvc_quality noaa and get wvc_quality_gen transform 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 Attribute Bit aM Bit 25 Description NOAA NOAA KNMI KNMI missing Flag not set all bits on qual_sigma0 15 32768 22 4194304 Not enough good o available for wind 37 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF Version 1 0 01 Reference Guide Date December 2011 Attribute Bit apit Bit 2 Description NOAA NOAA KNMI KNMI retrieval azimuth 14 16384 21 2097152 Poor azimuth diversity amo
137. utine latlon2ij gt ij2latlon mapxy Figure B6 2 Calling tree for routine ij2atlon gt printlceMap printlceAscat printlceQscat printopmcolor printopmvar Figure B6 3 Calling tree for routine printlceMap 96 Doc ID Version NWPSAF KN UD 006 1 0 01 December 2011 NWP SAF OWDP User Manual and Reference Guide Date Appendix C BUFR data descriptors Number Descriptor Parameter Unit 1 001007 Satellite Identifier Code Table 2 001012 Direction Of Motion Of Moving Observing Platform Degree True 3 002048 Satellite Sensor indicator Code Table 4 021119 Wind Scatterometer Geophysical Model Function Code Table 5 025060 Software Identification Numeric 6 002026 Cross Track Resolution m 7 002027 Along Track Resolution m 8 005040 Orbit Number Numeric 9 004001 Year Year 10 004002 Month Month 11 004003 Day Day 12 004004 Hour Hour 13 004005 Minute Minute 14 004006 Second Second 15 005002 Latitude Coarse Accuracy Degree 16 006002 Longitude Coarse Accuracy Degree 17 008025 Time Difference Qualifier Code Table 18 004006 Time to Edge Second 19 005034 Along Track Row Number Numeric 20 006034 Cross Track Cell Number Numeric 21 021109 SeaWinds Wind Vector Cell Quality Flag Table 22 011081 Model Wind Direction At 10 m Degree True 23 011082 Model Wind Speed At 10 m m s 24 021101 Number Of Vector Ambiguities Numeric 25 021102 Index Of Selected Wind Vector Numeric 26 021103 Tota
138. ying 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 OWDP 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_of GRIB_derived_ hour integer array Key to information in messages 68 OWDP User Manual and Doc ID NWPSAF KN UD 006 NWP SAF j Version 1 0 01 Reference Guide Date December 2011 Attribute Type Description list_of GRIB_par_id integer array Key to inf
139. ype 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 extent 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

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