gmscal [ parameter=value ... ] [ inputfile outputfile ] gmscal [ parameter=value ... ] [ inputfile ... directory ]
Parameters are: include_vars, temp_units, byte_output, base_temp, temp_step.
gmscal calibrates GMS VISSR data in gmsin created datasets. The calibration can be applied to either or both the visible or infrared data. The visible data is calibrated from raw count values (0-63) into percent albedo. The infrared data is calibrated from raw count values (0-255) into degrees temperature. The calibration is taken from tables (C.7 and C.8) provided in The GMS User's Guide 2nd Ed., Meteorlogical Satellite Center, Tokyo, Japan. March, 1989.
One output dataset is created for each input. Input datasets are byte data, output datasets are 1 or 2-byte data depending on the value of byte_output.
Specifies which variables in the input dataset(s) are to be calibrated and written to the output datasets. If this list is prefixed with a minus sign, all variables, except those listed, will be calibrated. Wildcards * and ? are allowed.
the manam_info variable is automatically 'skipped' in terms of calibration but is copied into the output datasets.
The default is all variables in the input dataset(s).
OPTIONAL. This determines the temperature units for calibrated IR data. Valid responses are [celsius, kelvin, fahrenheit]. The default is kelvin.
This specifies that the output dataset is to consist of 1-byte unsigned values rather than 2-byte values. For the visible channel, the effective range of the output data is 0-76.2 percent albedo at steps of .3 percent. The effective range of the calibrated infrared data is determined by the base_temp and temp_step parameters described below.
Valid responses are [yes or no]. The default is yes.
OPTIONAL. If byte_output=yes, these two parameters are used to convert temperature output to 8-bit values as follows:
8-bit value = nearest int( ( temp - base)/step )temp_step must be in the range [.1, 2.]. There are no restrictions on base_temp. The default values for base_temp and temp_step depend on temp_units. For Kelvin or Celsius, the default temp_step is .5. For Fahrenheit, the default temp_step is 1. The default values for temp_base are -85, 188.15, and -120 for Celsius, Kelvin, and Fahrenheit respectively.
The following example calibrates both the visible and infrared data of an intput GMS VISSR dataset. The output dataset (testcal1) will include calibrated visible and infrared data and the manam_info scheduling information variable. The output dataset will contain 1-byte data.
[1] % gmscal in/out files : char(255) ? testdata testcal1 include_vars : char(255) ? [] byte_output : char( 3) ? [yes]
The following example calibrates only the infrared data. The output dataset will include only the calibrated infrared data and the manam_info variable. The output dataset will contain 2-byte data.
[1] % gmscal in/out files : char(255) ? testdata testcal2 include_vars : char(255) ? [] svissr_ir1 byte_output : char( 3) ? [yes] no
The GMS User's Guide 2nd Ed., Meteorlogical Satellite Center, Tokyo, Japan. March, 1989.
Last Update: $Date: 1999/05/10 20:14:05 $