Table of Contents - The Atmospheric Studies Group at TRC

Section 6: SMERGE Surface Data Meteorological Preprocessor
SSSS
of feet)
= wind speed (XX.XX m/s)
For example, the following variables,
Temperature = 273.5 deg. K Precipitation code = 12
Relative humidity = 88 percent
Station pressure = 1012.4 mb
Opaque sky cover = 8 tenths
Wind direction = 160 degrees
Ceiling height = 120 hundreds of ft
Wind speed
= 5.65 m/s
are stored as the following three integer words:
273512088, 1012408160, 01200565
All of the packing and unpacking operations are performed internally by SMERGE and CALMET, and
are transparent to the user. The header records of the data file contain information flagging the file to
CALMET as a packed or unpacked file. If the user selects the unpacked format, eight full 4-byte words
are used to store the data for each station.
The input files used by SMERGE consist of a control file (SMERGE.INP) containing user inputs, up to
150 surface data files (one per surface station), and an optional SMERGE data file (formatted or
unformatted) created in a previous run of SMERGE. The data from the formatted surface station files are
combined with the data in the existing SMERGE data file. A new SMERGE output file (formatted or
unformatted) containing all the data is created by the program. In addition, SMERGE creates an output
list file (SMERGE.LST) which summarizes the user options and run time statistics. Table 6-3 contains a
listing of the input and output files used by SMERGE.
The SMERGE control file specifies the number and type of input data files, time zone of output data,
packing flag, station data (two lines per station), and the starting and ending dates of the period to extract.
The format of the SMERGE control input file follows the same rules as those used in the CALMET.INP
file (refer to the CALMET section for details). Only data within the delimiter characters (!) are processed.
The input data consist of a leading delimiter followed by the variable name, equals sign, input value or
values, and a terminating delimiter (e.g., !XX = 12.5!). SMERGE.INP may be created/edited directly
using a conventional editor, or it may be created/edited indirectly by means of the PC-based, Windowscompatible
Graphical User Interface (GUI) developed for the geophysical preprocessors (CALPRO). A
sample SMERGE control file is shown in Table 6-4. The format and contents of the SMERGE control
file are explained in Table 6-5.
The SMERGE output list file (SMERGE.LST) contains a summary of the control file inputs,
6-2