MET Online Tutorial

MET Online Tutorial for METv3.0

MODE Tool: General

MODE Functionality

MODE, the Method for Object-Based Diagnostic Evaluation, provides an object-based verification for comparing gridded forecasts to gridded observations. MODE may be used in a generalized way to compare any two fields containing data from which objects may be well defined. It has most commonly been applied to precipitation fields and radar reflectivity. The steps performed in MODE consist of:

  • Define objects in the forecast and observation fields based on user-defined parameters.
  • Compute attributes for each of those objects: such as area, centroid, axis angle, and intensity.
  • For each forecast/observation object pair, compute differences between their attributes: such as area ratio, centriod distance, angle difference, and intensity ratio.
  • Use fuzzy logic to compute a total interest value for each forecast/observation object pair based on user-defined weights.
  • Based on the computed interest values, match objects across fields and merge objects within the same field.
  • Write output statistics summarizing the characteristics of the single objects, the pairs of objects, and the matched/merged objects.

MODE may be configured to use a few different sets of logic with which to perform matching and merging. In this tutorial, we'll use the most simple approach, but users are encouraged to read the MET Users Guide for a more thorough description of MODE's capabilities.

MODE Usage

View the usage statement for MODE by simply typing the following:

    bin/mode

At a minimum, the input fcst_file in GRIB or NetCDF format (from PCP-Combine), the input obs_file in GRIB or NetCDF format (from PCP-Combine), and the configuration config_file must be passed in on the command line. Just as with Grid-Stat and Wavelet-Stat, the forecast and observation fields must be interpolated to a common grid prior to running MODE. The copygb utility is recommended for regridding files in GRIB format.