MODE Tool: Configure

The behavior of MODE is controlled by the contents of the configuration file passed to it on the command line. The default MODE configuration file may be found in the METv1.1/data/config/WrfModeConfig_default file. The configurations used by the test scripts may be found in the METv1.1/data/config/WrfModeConfig* files. Prior to modifying the configuration file, users are advised to make a copy of the default:

cp data/config/WrfModeConfig_default tutorial/config/WrfModeConfig_tutorial

Open up the tutorial/config/WrfModeConfig_tutorial file for editing with the text editor of your choice.

The configuration items for MODE are used to specify how the object-based verification approach is to be performed. Whereas in Point-Stat and Grid-Stat you may only compare the same type of forecast and observation fields, in MODE you may compare any two fields. When necessary, the items in the configuration file are specified separately for the forecast and observation fields. In most cases though, users will be comparing the same forecast and observation fields. The configurable items include specifications for the following:

• The forecast and observation fields and vertical levels or accumulation intervals to be compared.
• Options to mask out a portion of or threshold the raw fields.
• The forecast and observation object definition parameters.
• Options to filter out objects that don't meet a size or intensity criteria.
• Flags to control the logic for matching/merging.
• Weights to be applied for the fuzzy engine matching/merging algorithm.
• Interest functions to be used for the fuzzy engine mathcing/merging algorithm.
• Total interst threshold for matching/merging.
• Various plotting options.

While the MODE configuration file contains many options, beginning users will typically only need to modify a few of them. You may find a complete description of the configurable items in section 6.3.2 of the MET User's Guide or in the comments of the configuration file itself. Please take some time to review them.

For this tutorial, we'll configure MODE to verify the same 12-hour accumulated precipitation output of PCP-Combine that we used for Grid-Stat. MODE can read either GRIB files or the NetCDF output of PCP-Combine. Whereas Grid-Stat and Point-Stat may be used to compare multiple fields in one run, MODE compares a single forecast field to a single observation field. Edit the tutorial/config/WrfModeConfig_tutorial file as follows:

• Set grid_res = 40; to set the nominal grid spacing to 40km for this grid. The grid_res parameter is used further down in the config file in defining interest functions.


• Set fcst_grib_code = "APCP/A12"; to select the forecast field of 12-hour rainfall total accumulation.
• Set obs_grib_code = "61/A12"; to select the same observation field and illustrate that you may use the GRIB code 61 or the corresponding abbreviation APCP.


• Set fcst_conv_radius = 5; and obs_conv_radius = 5; to specify a convolution smoothing radius of 5 grid units. These parameters may be set explicity, as we're doing now, or relative to another value, like the grid_res parameter which was set above.
• Verify that fcst_conv_threshold = "ge5.0"; and obs_conv_threshold = "ge5.0"; to threshold the convolved fields and define objects. The ge portion indicates that the thresholding should be performed as greater than or equal to.


• Set fcst_merge_flag = 0; and obs_merge_flag = 0; to disable the double-thresholding merge option.