WRF Model Utilities: diffwrf

Purpose

- List the contents of a WRF input, output, restart, or boundary datasets.

- Extract a field in wgrib text output format, also suitable for plotting using HMV.

- Compare two WRF datasets and generate field-by-field difference statistics.

- Supported formats:

- NetCDF
- Native binary
- Grib1 (use wgrib directly)

Necessary Software

- NetCDF libraries needed for NetCDF version.
- No additional libraries needed for native-binary version.

Distribution and compilation

- diffwrf is distributed with WRF and built when WRF is configured and compiled.

- Excutables

- diffwrf for NetCDF is external/io_netcdf/diffwrf
- diffwrf for native binary I/O is external/io_int/diffwrf

Steps to Run Utility

- To list the fields of a dataset

diffwrf filename list

- To extract all time frames of a field in ascii form and write to the file fort.88

diffwrf filename fieldname [level]

Fieldname is the name of the field exactly as listed (case sensitive)

Level is an optional integer argument. If specified, only that level of a multi-level field will be output; otherwise, the entire field will be output

Note that the resulting fort.88 output file may be plotted to a X-window display device using the HMV tool with the following command:

hmv –3 fort.88

- To difference two wrf datasets

diffwrf filename1 filename2

For each field in each time frame stored in the files, diffwrf will display RMS, L2, and point-max differences. Note that the files must match in other respects; the sizes, number, types, and time stamps of the fields must be the same in each file.