Help for ASTERBTEMP

PURPOSE:

   ASTERBTEMP is a program that accepts as input the five ASTER TIR channels
of Level 1B data (Channels 10-14), and outputs the corresponding brightness 
temperatures for each channel at each pixel.


OPERATION:

   ASTERBTEMP requires as input a 5 channel ASTER TIR image dataset of
Level 1B data.  The input should be the raw Level 1B pixel values, not
values converted into radiance units. An internal lookup table is used to
supply the converted output values.  As with the ASTER Level 2 Brightness
Temperature product, pixels of no data (such as the skew wedges) are converted
to -27315.  Invalid input pixel values are output as +29999.

   To interpret the output pixel values as temperature, divide by 100.0,
and read as degrees Celsius.  For example, a pixel value of 1234 should be
interpreted as 12.34 degrees Celsius.

   This program produces results that differ from the DAAC generated product
by 1 DN in approximately 20 percent of all pixels.  There is no apparent +/-
bias in the differences.  This discrepancy arises from the fact that the
DAAC lookup table is not coincident with the radiance values that result from
the Level 1B DN to radiance conversion factors, and no interpolation is done
to compensate for this fact. The built in lookup table for this program is a
direct Level 1B DN to Brightness Temperature DN table, so no compensation is
needed.

WRITTEN BY:  Ron Alley         March 19,  2004

COGNIZANT PROGRAMMER:  Ron Alley

REVISION: New   19 March 2004