Configure

Start by making an output directory for Ensemble-Stat and changing directories:

mkdir -p ${METPLUS_TUTORIAL_DIR}/output/met_output/ensemble_stat

cd ${METPLUS_TUTORIAL_DIR}/output/met_output/ensemble_stat

The behavior of Ensemble-Stat is controlled by the contents of the configuration file passed to it on the command line. The default Ensemble-Stat configuration file may be found in the data/config/EnsembleStatConfig_default file. The configurations used by the test script may be found in the scripts/config/EnsembleStatConfig* files.

Prior to modifying the configuration file, users are advised to make a copy of the default:

cp ${MET_BUILD_BASE}/share/met/config/EnsembleStatConfig_default EnsembleStatConfig_tutorial

Open up the EnsembleStatConfig_tutorial file for editing with your preferred text editor.

vi EnsembleStatConfig_tutorial

The configurable items for Ensemble-Stat are similar to those found in Grid-Stat and Point-Stat: forecast and observation dictionaries read in the the ensemble and observation fields, respectively, while the remaining dictionaries and options control the computed statistics and the area over which those statistics are calculated.

You may find a complete description of the configurable items in the ensemble_stat configuration file section of the MET User's Guide. Please take some time to review them.

For this tutorial, we'll configure Ensemble-Stat to verify 24-hour accumulated precipitation. While we'll run Ensemble-Stat on a single field, please note that it may be configured to operate on multiple fields. The ensemble we're verifying consists of 6 members defined over the west coast of the United States.

Edit the EnsembleStatConfig_tutorial file as follows:

In the fcst dictionary, set

   field = [
     {
       name = "APCP";
       level      = [ "A24" ];
     }
   ];

To verify the 24-hour accumulated precipitation fields.
In the observation filtering options, set:

message_type = [ "ADPSFC" ];

To verify against surface observations.
In the field entry section, set:

prob_cat_thresh= [ >=0, >=5.0, >=10.0 ];

To specify thresholds to use for computation of the Ranked Probability Score (RPS).
In the mask dictionary, set

poly = [ "MET_BASE/poly/NWC.poly",
"MET_BASE/poly/SWC.poly" ];

To also verify over the northwest coast (NWC) and southwest coast (SWC) subregions.
Set:

output_flag = {
   ecnt = BOTH;
   rhist = BOTH;
   phist = BOTH;
   orank = BOTH;
   ssvar = BOTH;
   relp = BOTH;
}

To compute continuous ensemble statistics (ECNT), ranked histogram (RHIST), probability integral transform histogram (PHIST), observation ranks (ORANK), spread-skill variance (SSVAR), and relative position (RELP).

Save and close this file.

johnhg Thu, 07/25/2019 - 16:07