METplus Practical Session Guide (Version 5.0) | MET Tool: Point-Stat > Reconfigure

Point-Stat Tool: Reconfigure

Now we'll reconfigure and rerun Point-Stat.

Start by making a copy of the configuration file we just used:
cp PointStatConfig_tutorial_run1 PointStatConfig_tutorial_run2

This time, we'll use two dictionary entries to specify the forecast field in order to set different thresholds for each vertical level. Point-Stat may be configured to verify as many or as few model variables and vertical levels as you desire.

Edit the PointStatConfig_tutorial_run2 file as follows:
vi PointStatConfig_tutorial_run2
  • Set:
    fcst = {

       field = [

        {

          name       = "TMP";

          level      = [ "Z2" ];

          cat_thresh = [ >273, >278, >283, >288 ];

        },

        {

          name       = "TMP";

          level      = [ "P750-850" ];

          cat_thresh = [ >278 ];

        }

      ];

    }

    obs = fcst;

    to verify 2-meter temperature and temperature fields between 750hPa and 850hPa, using the thresholds specified.

  • Set:
    message_type = ["ADPUPA","ADPSFC"];

    sid_inc = [];

    sid_exc = [];

    obs_quality = [];

    duplicate_flag = NONE;

    obs_summary = NONE;

    obs_perc_value = 50;

    to include the Upper Air (UPA) and Surface (SFC) observations in the evaluation

  • Set:
    mask = {

       grid  = [ "G212" ];

       poly  = [ "MET_BASE/poly/EAST.poly",

                 "MET_BASE/poly/WEST.poly" ];

       sid   = [];

       llpnt = [];

    }

    to compute statistics over the NCEP Grid 212 region and over the Eastern and Western United States, as defined by the polylines specified.

  • Set:
    interp = {

       vld_thresh = 1.0;

       shape       = SQUARE;

       type = [

          {

             method = NEAREST;

             width  = 1;

          },

          {

             method = DW_MEAN;

             width  = 5;

          }

       ];

    }

    to indicate that the forecast values should be interpolated to the observation locations using the nearest neighbor method and by computing a distance-weighted average of the forecast values over the 5 by 5 box surrounding the observation location.

  • Set:
    output_flag = {

       fho    = BOTH;

       ctc    = BOTH;

       cts    = BOTH;

       mctc   = NONE;

       mcts   = NONE;

       cnt    = BOTH;

       sl1l2  = BOTH;

       sal1l2 = NONE;

       vl1l2  = NONE;

       val1l2 = NONE;

       pct    = NONE;

       pstd   = NONE;

       pjc    = NONE;

       prc    = NONE;

       ecnt   = NONE;

       eclv   = BOTH;

       mpr    = BOTH;

    }

    to switch the SL1L2 and CTS output to BOTH and generate the optional ASCII output files for them.

  • Set:
    output_prefix = "run2";

    to customize the output file names for this run.

Let's look at our configuration selections and figure out the number of verification tasks Point-Stat will perform:
  • 2 fields: TMP/Z2 and TMP/P750-850
  • 2 observing message types: ADPUPA and ADPSFC
  • 3 masking regions: G212, EAST.poly, and WEST.poly
  • 2 interpolations: UW_MEAN width 1 (nearest-neighbor) and DW_MEAN width 5

Multiplying 2 * 2 * 3 * 2 = 24. So in this example, Point-Stat will accumulate matched forecast/observation pairs into 24 groups. However, some of these groups will result in 0 matched pairs being found. To each non-zero group, the specified threshold(s) will be applied to compute contingency tables.

Can you diagnose why some of these verification tasks resulted in zero matched pairs? (Hint: Reread the tip two pages back!)