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, centroid 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 Chapter 6 of the MET User's Guide for a more throrough description of MODE's capabilities.

MODE Usage

From the top level METv3.1_beta2 directory, view the usage statement for MODE by simply typing the following:

bin/mode

Usage: mode
	fcst_file	Input forecast file in either GRIB or netCDF format (output of pcp_combine) containing the field to be verified
	obs_file	Input observation file in either GRIB or netCDF format (output of pcp_combine) containing the verifying field
	config_file	MODEConfig file containing the desired configuration settings
	[-config_merge merge_config_file]	Overrides the default fuzzy engine settings for merging within the fcst/obs fields (optional).
	[-fcst_valid time]	For forecast files with multiple output times, set the time to be verified in YYYYMMDD[_HH[MMSS]] format (optional)
	[-fcst_lead time]	For forecast files with multiple lead times, set the lead time to be verified in HH[MMSS] format (optional)
	[-obs_valid time]	For observation files with multiple output times, set the time to be verified in YYYYMMDD[_HH[MMSS]] format (optional)
	[-obs_lead time]	For observation files with multiple lead times, set the lead time to be verified in HH[MMSS] format (optional)
	[-outdir path]	Overrides the default output directory (optional).
	[-plot]	Disables plotting (optional).
	[-obj_plot]	Disables the output of the object split and cluster fields to a NetCDF file (optional).
	[-obj_stat]	Disables the output of the object statistics file (optional).
	[-ct_stat]	Disables the output of the contingency table standard statistics file (optional).
	[-log file]	Outputs log messages to the specified file
	[-v level]	Level of logging

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, 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.