GSI Tools Functionality
The Gridpoint Statistical Interpolation (GSI) system is a variational data assimilation system often run with the WRF model. GSI processes several observation data types and matches them to the model grid. GSI has the option of generating binary diagnostic files which contain information about that paired data. The GSI Tools in MET were designed to read those binary diagnostic files and dump their contents to ASCII files formatted so they can be further processed by the STAT-Analysis tool.
The GSI Tools are able to read conventional and radiance diagnostic files. Support for additional data types will be added in future releases. There are two GSI Tools: GSID2MPR and GSIDENS2ORANK. The GSID2MPR tool reads one or more GSI diagnostic file(s) and writes output in the MET matched pair (MPR) line type. It writes several extra columns of data to the end of the MPR lines based on input data type. Run this tool to create MPR data and pass it to the STAT-Analysis tool to compute additional statistics.
The GSIDENS2ORANK tool reads an ensemble of GSI diagnostic files and writes output in the MET observation rank (ORANK) line type. It writes several extra columns of data to the end of the ORANK lines based on input data type. Run this tool to create ensemble ORANK data and pass it to the STAT-Analysis tool to compute additional statistics.
GSI Tools Usage
View the usage statement for GSI Tools by simply typing the following:
You must pass one or more GSI diagnostic file names to GSID2MPR. For each input file, it writes an output file to the -outdir directory using the .stat suffix or the string specified by the -suffix option.
You must pass the GSI diagnostic file names for all ensemble members to GSIDENS2ORANK and the output file name using the -out option. Use -ens_mean to specify the ensemble mean data or the mean for each observation location will be computed on the fly from the member values.
