Community GSIV3.7 Online Tutorial | Case 7: 4D Hybrid EnVar Case > Setting up the Run Script for GSI 4D hybrid analysis

GSI 4D HYBRID FOR ARW USING GLOBAL ENSEMBLE FORECAST

Setting up the Run Script for GSI 4D hybrid analysis

Copy the sample run script run_gsi_regional.ksh from the practical case 3 (ARW 3DVAR with PrepBUFR) to a working directory and make the following modifications to run GSI 4D hybrid analysis:

• set the analysis time to 
  ANAL_TIME=2017051318
• Set the name/path for the analysis run directory to
• WORK_ROOT=${run directory}
• Set the location of the ensemble files in the variable ENS_ROOT=...
• set the BK_ROOT to where you store the background files, WRF forecast at 3 time levels
• set the path to the background file at the analysis time 
  BK_FILE=${BK_ROOT}/wrfout_d01_2018-08-12_18:00:00
• set to run 4D hybrid analysis 
  if_hybrid=Yes 
if_4DEnVar=Yes

As can be seen in the sample run script, for ${if_4DEnVar} = Yes, there are two additional background files at 1 hour before and after the analysis time, as specified in the variable BK_FILE_M1 and BK_FILE_P1; there are also two additional sets of ensemble files before and after the analysis time, as specified in the variable ENSEMBLE_FILE_mem_m1 and ENSEMBLE_FILE_mem_p1. Please make sure those variables setup right.

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