An algorithm for correction of lunar contamination in AMSU-A data

An algorithm is developed for detection and connection of the lunar contaminaion observed in the Advanced Microwave Sounding Unit (AMSU-A) data. Occurence of the lunar contamination has been observed several times per year with an irregular period. Over each orbit of data, about 200 scans may be contaminated during the lunar contamination occurence that may last as long as 24 hours and the closest time interval between two occurences is 28 days. The algorithm is modeled using the lunar position and phase. Combined with the measured AMSU-A antenna pattern, the algorithm executes a line-by-line detection and connection of the lunar contamination induced in the AMSU-A cold space radiometric counts when the Moon moves across the AMSU-A cold calibration field of views. The model can accurately detect and remove most of the lunar contamination from the cold space counts. Test results show that more than 90% of the lunar contamination can be eliminated from the AMSU-A cold space counts. A set of computer software is under development to incorporate this algorithm into the NESDIS operational preprocessor for improving the AMSU-A calibration accuracy. Seiichiro Kigawa and Tsan Mo. "December 2002." Also available online in PDF via the NOAA Central Library. Includes bibliographical references (page 12). 2002 NESDIS (National Environmental Satellite, Data, and Information Service) Library Public Domain 2286