Configure

Series-Analysis Tool: Configure

Start by making an output directory for Series-Analysis and changing directories:

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

cd ${METPLUS_TUTORIAL_DIR}/output/met_output/series_analysis

The behavior of Series-Analysis is controlled by the contents of the configuration file passed to it on the command line. The default Series-Analysis configuration file may be found in the data/config/SeriesAnalysisConfig_default file.

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

cp ${MET_BUILD_BASE}/share/met/config/SeriesAnalysisConfig_default SeriesAnalysisConfig_tutorial

The configurable items for Series-Analysis are used to specify how the verification is to be performed. The configurable items include specifications for the following:

The forecast fields to be verified at the specified vertical level or accumulation interval.
The threshold values to be applied.
The area over which to limit the computation of statistics - as predefined grids or configurable lat/lon polylines.
The confidence interval methods to be used.
The smoothing methods to be applied.
The types of statistics to be computed.

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

For this tutorial, we'll run Series-Analysis to verify a time series of 3-hour accumulated precipitation. We'll use GRIB1 for the forecast files and NetCDF for the observation files. Since the forecast and observations are different file formats, we'll specify the name and level information for them slightly differently.

Open up the SeriesAnalysisConfig_tutorial file for editing with your preferred text editor and edit it as follows:

vi SeriesAnalysisConfig_tutorial

Set the fcst dictionary to

fcst = {
   field = [
      {
        name = "APCP";
        level = [ "A3" ];
      }
   ];
}

To request the GRIB abbreviation for precipitation (APCP) accumulated over 3 hours (A3).
Delete obs = fcst; and insert

obs = {
   field = [
      {
        name = "APCP_03";
        level = [ "(*,*)" ];
      }
   ];
}

To request the NetCDF variable named APCP_03 where its two dimensions are the gridded dimensions (*,*).
Look up a few lines above the fcst dictionary and set

cat_thresh = [ >0.0, >=5.0 ];

To define the categorical thresholds of interest. By defining this at the top level of config file context, these thresholds will be applied to both the fcst and obs settings.
In the mask dictionary, set

grid = "G212";

To limit the computation of statistics to only those grid points falling inside the NCEP Grid 212 domain.
Set

block_size = 10000;

To process 10,000 grid points in each pass through the data. Setting block_size larger should make the tool run faster but use more memory.
In the output_stats dictionary, set

   fho    = [ "F_RATE", "O_RATE" ];
   ctc    = [ "FY_OY", "FN_ON" ];
   cts    = [ "CSI", "GSS" ];
   mctc   = [];
   mcts   = [];
   cnt    = [ "TOTAL", "RMSE" ];
   sl1l2 = [];
   pct    = [];
   pstd   = [];
   pjc    = [];
   prc    = [];

For each line type, you can select statistics to be computed at each grid point over the series. These are the column names from those line types. Here, we select the forecast rate (FHO: F_RATE), observation rate (FHO: O_RATE), number of forecast yes and observation yes (CTC: FY_OY), number of forecast no and observation no (CTC: FN_ON), critical success index (CTS: CSI), and the Gilbert Skill Score (CTS: GSS) for each threshold, along with the root mean squared error (CNT: RMSE).

Save and close this file.

johnhg Thu, 07/25/2019 - 23:03