GSI analysis at 18Z

GSI CYCLING RUN ARW BACKGROUND

GSI analysis at 18Z

For this step of GSI analysis at 18Z of August 12, 2018, we will use the 6-hour forecast output from the WRF run at 12Z as the background and conventional observations at 18Z. The steps to set up the GSI analysis is very similar to case 03, except for the background field and observations. The example run script can be found here.

Running the GSI run Script and checking the results

After GSI runs, a run directory will be created according to the path set in the variable WORK_ROOT. The contents of this run directory are provided in the following list .

The standard output file stdout and the fit files for this GSI run: temperature (fit_t1); wind (fit_w1); moisture (fit_q1).

Convergence information (section 4.6 of the GSI User's Guide) is available in the file: fort.220

WRF-ARW run at 18Z

As a continued data assimilation run, the 18Z GSI analysis from the above step is then used as the initial field, together with the WRF background conditions at 18Z, to launch the WRF forecast at 18Z. The steps are very similar to the WRF run at 12Z and therefore not repeated here.