Intermediate File Format

Fields are written to the intermediate files as 2–dimensional horizontal slabs of data. Each horizontal slab contains a single level of a single variable (i.e., 500 mb RH, surface T, etc.). Any number of horizontal slabs may be written to a single file. The slabs in a given file are not necessarily all from the same data source, or all on the same grid or map projection, but they should all represent the data valid at the same time.

Each file contains data for a single time. The file names consist of a prefex (ideally, but not necessarily, denoting the source of data), followed by a colon, followed by a time–stamp in the form YYYY–MM–DD_HH.

The files are written as unformatted FORTRAN records. For each horizontal data slab a number of records are written. The number of records depends on the intermediate file version. Typical information in these records is:

– A version number
– Information common to all types of gridded data
– Information specific to the particular grid type represented
– A 2–dimensional slab of data

The intermediate file format was originally developed for the MM5 model. Due to its easy use, this file format has been passed on to the WRF modeling system. To fulfill extra requirements, various versions of this format are currently in use. The WPS package can read all the different versions, so users with older intermediate file formats can still use this data as input to the WPS. A switch in the namelist.wps file (out_format) gives users control over the version they are using as input.

WPS format (outformat = "WPS")
WRFSI format (outformat = "SI")
MM5 format (outformat = "MM5")

Detailed information regarding intermediate file formats are available from Chapter 3 of the Users' Guide.