SeaDAS 5.1 problem processing Terra L1B with v33 cal LUTs (FIXED)

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SeaDAS 5.1 problem processing Terra L1B with v33 cal LUTs (FIXED)

by obdaac_forum_user » Wed Sep 19, 2007 1:45 pm America/New_York

There appears to be a problem when processing recent MODIS Terra data (from September 18th onward) from Level-1A to Level-1B when using calibration LUTs newer than version 32a. Until this problem is rectified it is suggested  to revert back to the version 32a LUTs, e.g.:

http://oceans.gsfc.nasa.gov/MODIST/CAL/MOD02_Emissive_LUTs.V5.0.6.32a.hdf
http://oceans.gsfc.nasa.gov/MODIST/CAL/MOD02_QA_LUTs.V5.0.6.32a.hdf
http://oceans.gsfc.nasa.gov/MODIST/CAL/MOD02_Reflective_LUTs.V5.0.6.32a.hdf

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SeaDAS 5.1 problem processing Terra L1B with v33 cal LUTs (FIXED)

by obdaac_admin » Wed Nov 21, 2007 2:51 pm America/New_York

This problem has been fixed and is available in the SeaDAS 5.1 Update 06 (and MODISL1DB 1.4.1).

The update fixes a problem in the MOD_PRO2 (terra_l1bgen) processing code that was causing MODIS-Terra L1A to L1B processing to fail depending on which calibration LUT versions were being used. The issue was determined (by MODAPS and the OBPG) to involve the RVS correction limits set in the PreprocessP.h file. The threshold values have been relaxed in the PreprocessP.h header file from:

#define RVS_CORRECTION_UPPER_LIMIT  1.2e+0
#define RVS_CORRECTION_LOWER_LIMIT  8.0e-1

to:

#define RVS_CORRECTION_UPPER_LIMIT  2.4e+0
#define RVS_CORRECTION_LOWER_LIMIT  4.0e-1

This change appears to fix the problem. The new terra_l1bgen binary should now work with any past and future calibration LUTs.

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