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GSI Data Assimilation System

WRF-DA Tutorial, 20-22 July, 2009, Boulder, CO. GSI Data Assimilation System. Hui Shao, Ming Hu, Laurie Carson, Louisa Nance, Xiang-Yu Huang, Bill Kuo Developmental Testbed Center John Derber, Russ Treadon NOAA/NCEP/Environmental Modeling Center. Acknowledgement: NOAA, AFWA, NCAR.

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GSI Data Assimilation System

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  1. WRF-DA Tutorial, 20-22 July, 2009, Boulder, CO GSI Data Assimilation System Hui Shao, Ming Hu, Laurie Carson, Louisa Nance, Xiang-Yu Huang, Bill Kuo Developmental Testbed Center John Derber, Russ Treadon NOAA/NCEP/Environmental Modeling Center Acknowledgement: NOAA, AFWA, NCAR

  2. Primary Developers • NOAA/NCEP/EMC • John Derber,Jim Purser, Russ Treadon, Wan-Shu Wu, Dave Parrish, Lidia Cucurull, Dave Parrish, Manuel Pondeca, Paul van Delst, Daryl Kleist, Xiujuan Su, Yanqiu Zhu, and others • NASA/GMAO • Ricardo Todling, Ron Errico, Runhua Yang, Ron Gelaro, Wei Gu, and others • And NOAA/GSD, NCAR/MMM,…

  3. Session Outline • GSI System and Community Support (30 minutes, presented by Hui Shao) • Installation, Running, and Diagnostics (30 minutes, presented by Ming Hu)

  4. GSI System 4

  5. Gridpoint Statistical Interpolation (GSI) • 3D variational assimilation (same as WRF-VAR) • J =1/2 (x-xb)TB-1(x-xb) + 1/2(H(x)-y0)T(E+F)-1(H(x)-y0) + JC • Fit to background + Fit to observations + constraints • x = Analysis (Output) • xb = Background (Input) • B = Background error covariance (Input) • H = Forward model (within GSI) • y0 = Observations (Input) • E+F = R = Instrument error + Representativeness error (Input) • JC = Constraint terms (within GSI)

  6. Operational GSI Applications * Collaborated with NASA/GMAO and others 6

  7. NAM HWRF Rapid Refresh Domain Air Force Weather Agency Domains

  8. GSI Code Flow Read in & distribute observations, background & background errors Additional initializations User input & initializations • Outer loop • a) Set up right hand side of analysis equation • (Compute observation innovations) • b) Call inner loop • Compute gradient information • Apply background error • Compute search direction • Compute step size • Update analysis increment Write analysis & related output

  9. Background Fields (xb) • Currently works for the following systems • Global • GFS • GMAO global • Regional • WRF (ARW & NMM) - binary and netcdf • NCEP RTMA

  10. Radiosondes Pibal winds Synthetic tropical cyclone winds Wind profilers Conventional aircraft reports ASDAR aircraft reports MDCARS aircraft reports** Dropsondes MODIS IR and water vapor winds GMS, METEOSAT and GOES cloud drift IR and visible winds GOES water vapor cloud top winds Surface land observations* Surface ship and buoy observation SSM/I wind speeds QuikScat wind speed and direction SSM/I precipitable water SSM/I and TRMM TMI precipitation estimates Doppler radial velocities VAD (NEXRAD) winds GPS precipitable water estimates GPS Radio occultation refractivity profiles SBUV ozone profiles (other ozone data under test) Observations(yo) *Some of the data are restricted

  11. Regional GOES-11 and 12 Sounders – thinned to 120km Channels 1-15     Individual fields of view     4 Detectors treated separately     Over ocean only AMSU-A – thinned to 60km    NOAA-15     Channels 1-10, 12, 15     NOAA-18     Channels 1-8, 10-11, 15 AMSU-B/MHS – thinned to 60km     NOAA-15     Channels 1-3, 5     NOAA-16     Channels 1-5     NOAA-17    Channels 1-5     NOAA-18    Channels 1-5 HIRS – thinned to 120km    NOAA-17    Channels 2-15 Global GOES-11 and 12 Sounders –thinned to 180km    Channels 1-15     Individual fields of view     4 Detectors treated separately     Over ocean only AMSU-A – thinned to 145km    NOAA-15    Channels 1-10, 12-13, 15     NOAA-18    Channels 1-8, 10-13, 15     METOP       Channels 1-13, 15     AQUA          Channels 1-6, 8-13, 15 AMSU-B/MHS – thinned to 240km     NOAA-15     Channels 1-3, 5     NOAA-16     Channels 1-5     NOAA-17    Channels 1-5     NOAA-18    Channels 1-5     METOP        Channels 1-5 HIRS - thinned to 180km    NOAA-17    Channels 2-15     METOP        Channels 2-15 AIRS – thinned to 180km    AQUA        148 Channels Observations(yo) (cont.)

  12. Observation Operator (H) • To use observation, GSI simulates observation using analysis variables – observation operator (H) • Can be simple interpolation to ob location/time. • Can be more complex (e.g., radiation transfer). • For radiances, GSI uses CRTM.

  13. Background Errors (B) • Space correlation computed using recursive filters in horizontal and vertical • Multivariate relation • Flow dependent variability in background error • Background error variances modified based on 9 and 3 hour forecast differences: • Variance increased in regions of rapid change • Variance decreased in “calm” regions • Global mean variance ~ preserved • Being used for regional (US) surface analysis operationally.

  14. HPC Surface Analysis b) with flow dependent re-scaling L rescaled a) without re-scaling “as is” Surface pressure background error standard deviation fields Valid at 00Z November 06, 2007

  15. Moisture analysis • Option 1: univariate • Temperature (blue) increment forces large increment in RH (shaded). • Option 2: multivariate • Temperature (blue) increment • forces increment in q (red). • much smaller RH (shaded) increment.

  16. Observation Errors • Improved specification of observational errors • Adaptive Tuning After tuning After tuning and smoothing Before tuning

  17. Observation Quality Control • External platform specific QC • Some gross checking in PREPBUFR file creation • Optimal interpolation quality control (OIQC) – on its way out • Analysis QC • Gross checks – specified in input data files • Variational quality control (VarQC) – implemented operationally in Feb 2009 Number of data rejected by OIQC VarQC weight (W)

  18. Bias Correction of Radiance Data • NCEP uses a two step process for Tb • Scan angle correction – based on position • Air mass correction – based on predictors • Predictors • mean • path length (local zenith angle determined) • integrated lapse rate • integrated lapse rate ** 2 • cloud liquid water

  19. 19V 19H 22V 37V 37H 85V 85H B-O Histogram DMSP15 July2004 : 1month before bias correction after bias correction

  20. Community Support 20

  21. Community GSI Code DTC Research Community • Goals: • Provide current operational GSI capability to the research community (O2R) • Provide a framework for distributed development of new capabilities & advances in data assimilation (R2O)

  22. Definition of Community Codes • Free and shared resource • Ongoing distributed development by both research and operational communities • Maintained under version control • Periodic releases made available to the community • Includes latest developments of new capabilities and techniques • Centralized support • Provided in collaboration with developers

  23. GSI Community Release Timetable With user support Residential tutorial and hand-on practical session

  24. Code Management Plan DTC Community Repository Developers release Community Community GSI Code Repository Proposed Structure NCEP EMC Repository Success of this structure will depend on communication and collaboration among all GSI developers, users, and DTC.

  25. Release announcement System component descriptions Documentation User’s Guide Presentations Registration Software downloads Bug fix reports User support information gsi_help@ucar.edu Tutorial information User’s Website http://www.dtcenter.org/com-GSI/users/

  26. GSI User’s Guide User’s Guide will be updated to be consistent with each new release to the community.

  27. On-line Tutorial (Beta Release)

  28. On-line Documents (Beta Release)

  29. GSI Web Brower

  30. O2R2O2R2O2R2O2R2O …

  31. GSI: Compile 31

  32. Requirements • System required libraries • FORTRAN 90/95 compiler • C compiler • Perl • netCDF • GSI system • Download GSI system tar files (GSIbeta.tar.gz ) from http://www.dtcenter.org/com-GSI/users/index.php • gunzip and untar tar –zxvf GSIbeta.tar.gz (Should see GSI/. directory ) • cd to GSI directory cd GSI 32

  33. GSI Directory Compile rules Compile scripts Source code directory Run directory

  34. Set environment • WRF_DIR • WRF needs to be compiled prior to compiling GSI • GSI uses WRF I/O API libraries to do file input and output • WRF directory specified: • setenv WRF_DIR /home/user/WRFV3 • netCDF • If netCDF libraries are not located in the standard /usr/local , then • setenv NETCDF “path for netCDF” • For LINUX systems, make sure the netCDFlibraries are installed using the same compiler (PGI, Intel, g95) that will be used to compile GSI. 34

  35. Configuring GSI • To create a GSI configuration file for your computer: • ./configure • This script checks the system hardware and software (mostly netCDF), and then offers the user choices for configuring GSI: • Choices for 32-bit LINUX operated machines are: • 1. Linux i486 i586 i686, PGI compiler • 2. Linux i486 i586 i686, Intel compiler • 3. Linux i486 i586 i686, gfortran compiler • Choices for IBM machines are: • 1. AIX xlf compiler with xlc 35

  36. Configuring GSI, cont. • configure.gsi • Created by the ./configure command • contains compilation options, rules, etc. • specific to your computer • can be edited to change compile options, if desired. • At this time, the IBM option is well tested. Working on Linux option test. • The arch/configure.defaultsfile can be editedto add a new option if needed. 36

  37. Compiling GSI • To compile: ./compile >& compile_gsi.log • To get compile help message: ./compile -h • If the compilation is successful, it will create one executable under bin/: • gsi.exe 37

  38. Clean Compilation • To remove all object files and executables ./clean • To remove all built files, including configure.gsi ./clean –a • Clean is recommended if • compilation failed • want to change configuration file 38

  39. Running GSIUser’s Guide: Chapter 3

  40. GSI Executable Background (first guess) file Observations Not needed for single observation experiment Fixed files (within GSI package) Run script (namelist included) To run GSI, you need:

  41. GSI can use WRF NMM input file in binary format WRF NMM input file in netcdf format WRF ARW input file in binary format WRF ARW input file in netcdf format GFS input file in binary format GMAO global model input file in binary format DTC has only tested regional analysis with WRF input On IBM: both binary and nedcdf format On Linux: netcdf format only Background

  42. All observations have to be in BUFR format prepbufr: NCEP flavor BUFR Need NCEP BUFR library Observation

  43. Collection of statistic and control files under fix directory Background and observation errors berror_stats, errtable Observation data control file (info files) convinfo , satinfo Bias correction used by radiance analysis satbias_angle, satbias_in Radiance coefficient used by CRTM EmisCoeff.bin, CloudCoeff.bin Fixed files

  44. Ask for computer resources to run GSI Set environment variables for the machine Set experiments variables (experiment name, analysis time, background and observation) Check the definition of required variables Generate a run directory for GSI (working or temp directory) Copy GSI executable to run directory Copy background file to run directory Copy or link observations to run directory Copy fixed files to run directory Generate namelist for GSI Run the GSI executable Save the GSI analysis results Run script - structure

  45. # analysis time (YYYYMMDDHH) ANAL_TIME=2008051112 # working direcotry, where GSI runs WORK_ROOT=./gsi/case # path and name of background file BK_FILE=./2008051112/bkARW/wrfout_d01_2008-05-11_12:00:00 # path of observations OBS_ROOT=./gsi/case PREPBUFR=./tutorialcases/data/newgblav.gdas1.t12z.prepbufr.nr # path of fix files FIX_ROOT=./GSI/fix # path and name of the gsi executable GSI_EXE=./GSI/bin/gsi.exe # which background error covariance and parameter will be used (GLOBAL or NAM) bkcv_option=NAM Run Script - Experiment variables

  46. Run directory Create a new directory for each run Copy or link data Executable Background Must be copied, will be over-written by analysis result Observations Link or touch if not exist Fixed files Link Run Script - run directory

  47. Generated by running scripts Change namelist by editing run script Works for both global and regional analysis Detailed explanation in section 3.4 Run Script : namelist &SETUP miter=2,niter(1)=5,niter(2)=5, write_diag(1)=.true.,write_diag(2)=.false.,write_diag(3)=.true., qoption=1, gencode=78,factqmin=0.005,factqmax=0.005,deltim=$DELTIM, ndat=59,npred=5,iguess=-1, oneobtest=.false.,retrieval=.false.,l_foto=.false., use_pbl=.false., $SETUP / &GRIDOPTS JCAP=$JCAP,NLAT=$NLAT,NLON=$LONA,nsig=$LEVS,hybrid=.true., wrf_nmm_regional=.false.,wrf_mass_regional=.true., diagnostic_reg=.false., filled_grid=.false.,half_grid=.true.,netcdf=.true., regional=.true.,nlayers(63)=3,nlayers(64)=6, $GRIDOPTS

  48. Tuning and DiagnosticsUser’s Guide: Chapter 4

  49. Includes lots of important information First place to look after any GSI run If successful Data distribution Optimal iteration Maximum and minimum of analysis fields If fails, which part of GSI has problem what is the possible reason for failure Standard out file - stdout

  50. stdout - structure • read in all data and prepare analysis: • read in configuration (namelist) • read in background • read in constant file (fixed file) • read in observation • partition background and observation data for parallel analysis • optimal iteration (analysis) • save analysis result

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