Case 4: 3DVAR with conventional data (PrepBUFR) plus other data

Case 4: 3DVAR with conventional data (PrepBUFR) plus other data cindyhg Tue, 07/16/2019 - 10:50

3DVAR GSI USING ARW BACKGROUND (PREPBUFR AND OTHER OBS)

Introduction

This exercise consists of running the GSI analysis with an ARW netcdf formatted background field, conventional data from prepbufr, satellite radiances, gpsro and radar data.

Further information on setting up the run is available in chapter 3 of the GSI User's Guide.

The ARW background field is provided in netcdf format, and the regional NAM BE is employed as the background error covariance.

Setting up the Run Script

Setting up the Run Script cindyhg Tue, 07/16/2019 - 10:51

3DVAR GSI USING ARW BACKGROUND (PREPBUFR AND OTHER OBS)

Setting up the Run Script

For this exercise, make a copy of the previously prepared run script:
cp run_gsi_regional.ksh_basic run_gsi_regional.ksh.

Make the following additional modifications to the script run_gsi_regional.ksh:

Set the name/path for the analysis run directory to

WORK_ROOT=${run directory}

Select the background field format bk_core=ARW

Select the NAM regional background error covariance bkcv_option=NAM

Open the links to the radiance data, gpsro and radar data by un-commenting the following line:

ln -s ${srcobsfile[$ii]} ${gsiobsfile[$ii]}

An example of this run script is available from the link run_gsi_regional.ksh

Running the Script

Running the Script cindyhg Tue, 07/16/2019 - 10:51

3DVAR GSI USING ARW BACKGROUND (PREPBUFR AND OHTER OBS)

Running the Script

For this example, GSI is run as a 4-core MPI job. If you run on PBS system (Cheyenne), type:

qsub run_gsi_regional.ksh

to launch the job.

The progress of the job can be monitored by examining the tail of the standard out file in the run directory as specfied in the variable WORK_ROOT:

tail stdout

The contents of this run directory are provided in the following list.

Results

Results cindyhg Tue, 07/16/2019 - 10:52

3DVAR GSI USING ARW BACKGROUND (PREPBUFR AND OTHER OBS)

Results

The standard output file stdout contains the run diagnostics, such as convergence information, and observation distribution from the GSI run. Details of the standard output file are available in section 4.1 of the GSI User's Guide.

Information about the use of observations by the analysis, and the corresponding innovations are available from the fit files (named fort.2*). The fit files located in the run directory should agree with the following fit files for temperature (fit_t1); wind(fit_w1); moisture (fit_q1); surface pressure (fit_p1); and radiance (fit_rad1); and GPS (fort.212); and radar radial velocity(fort.209).

Convergence information is available in the file: fort.220

Visualizing the Analysis

The model analysis may be visualized through modifying the ncl script Analysis_increment.ncl provided with the community GSI under ./util/Analysis_Utilities/plots_ncl. This script plots the data impact from additional satellite radiance, gpsro and radar data (analysis with conventional, satellite radiance, gpsro and radar data minus analysis with conventional data only) at level 31.

To visualize your output, copy the ncl script to run directory and make the following changes:

Set: cdf_analysis = addfile("wrf_inout.cdf","r") to point to analysis results

Set: cdf_bk = addfile("${Path to case 3 result}/wrf_inout.cdf","r") point to case 3 analysis file.

Set: kmax=20 for plot at level 21

The sample scripts for these plots can be found at GSI_Analysis_increment.ncl

Once you have customized the script for your output directory, run the script with the command:
ncl Analysis_increment.ncl
Once done a pdf file GSI_Analysis_increment_20.pdf will be generated in the run directory. Compare these images with the reference solution [PDF].