Help for L7CAL

PURPOSE:

   L7CAL is a program which calibrates the LANDSAT-7 thermal channel data 
to ground radiance or ground temperature. The input is LANDSAT-7 data which 
have already been calibrated to instrument radiance 
(in milliWatts/square meter/steradian/micrometer).

EXECUTION:

   The following is the execution statement format for L7CAL:

	L7CAL INP=PIX OUT=CALPIX PARAMS

   where INP, OUT, and PARAMS are parameters discussed in their res-
pective parameter sections. 



OPERATION:

   L7CAL takes as input the radiance at sensor for the LANDSAT-7 thermal
channel. It uses MODTRAN to compute the atmospheric path radiance, 
transmittance, and ground reflected atmospheric radiance. These values are 
convolved with the LANDSAT-7 spectral response functions and the instrument 
perceived radiances to obtain either ground radiance, ground temperature, or 
emittance.  The formula used to compute ground radiance is:

        IRAD = [GRAD + (1.0-e)*L   ]*Trans + L
                                sky           path

   The units output for radiance images are in milliwatts/m**2/um/sr. The units 
output for temperature images are in hundredths of degrees Celsius. Output 
is in halfword (two byte signed integer) format. 


WRITTEN BY:  Ron Alley  27 August 1999

COGNIZANT PROGRAMMER:  Ron Alley

REVISION: New

PARAMETERS:

INP

(1) LANDSAT-7 thermal channel, radiance at sensor (mW/m^2/sr/um) (2) Radiance to temperature lookup table (Not needed if CALMODE=GRAD)

OUT

Output data set of surface radiance or temperature

SIZE

The standard VICAR2 output size field.

SL

Starting line

SS

Starting sample

NL

Number of lines

NS

Number of samples

CALMODE

This keyword selects the type of decalibatrion to be performed Valid: GRAD, GTEM, BTEM

AMODEL

Selects the model for which the atmospheric corrections will be performed via MODTRAN

ATEMP

Selects atmospheric temperature and pressure profiles, if different form that defaulted with AMODEL.

AHUMID

Selects the atmospheric water vapor model, if different from that defaulted with AMODEL.

AOZONE

Selects the ozone model, if different from that defaulted with AMODEL.

DATUM

Surface elevation (km above MSL)

NLAYERS

The number of atmospheric lay- ers in the radiosonde data (if used).

ALTITUDE

The altitudes of each of the atmospheric layers given in the radiosonde data. (km. above MSL)

PRESSURE

The atmospheric pressures of each of the atmospheric lay- ers given in the radiosonde data. (mb.)

TEMP

The temperatures of the at- mospheric layers given in the radiosonde data. Units are either Celsius (the default) or Kelvin, if the KELVIN keyword has been specified.