Table of Contents - The Atmospheric Studies Group at TRC

Section 8: CALMET Model Files
8.4 Surface Meteorological Data File (SURF.DAT)
CALMET provides two options for the format of the surface meteorological data input file, SURF.DAT.
The first is to use the unformatted file created by the SMERGE meteorological preprocessor program.
SMERGE processes and reformats hourly surface observations in standard NCDC formats into a form
compatible with CALMET. It is best used for large data sets with many surface stations.
The second format allowed by CALMET for the SURF.DAT file is a free-formatted option. This option
allows the user the flexibility of either running the SMERGE preprocessor to create a formatted data file
or for short CALMET runs, manually entering the data.
The selection of which surface data input format is used by CALMET is made by the user with the
control file variable, IFORMS (see Input Group 4 of the control file in Section 8.1).
A sample formatted SURF.DAT file is shown in Table 8-11. A description of each variable in the
formatted surface data file is contained in Table 8-12. The first line of the file identifies the file and its
format to CALMET. The second line provides the number of comment lines (character strings of up to
80 characters in length) to follow that are read but are not interpreted by the model. One of these may
typically contain a title to identify the data set. The next line after all comment records identifies the map
projection for any locations provided in the file. Presently, the projection is NONE as no locations are
provided. The next record identifies the time zone of the data in the file, which is denoted as the time to
add to UTC (e.g., the Eastern Standard Time zone in the USA is UTC-0500). The next line identifies the
beginning and ending dates and times of data in the file and the number of stations. Finally, one record
per station follows with the station ID for each. One data record per hour follows the header records.
Each data record contains the date and time and for each station, the wind speed, wind direction, ceiling
height, cloud cover, temperature, relative humidity, station pressure, and a precipitation code.
Buoy and other overwater data are normally input through the SEAn.DAT files. If the overwater method
is not used, the buoy data can be either the SURF.DAT file or SEAn.DAT files. In any case, buoy data
for a given station should not be in both files.
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