Degradation of the VISSR visible sensor on GMS-3 during June 1987- December 1988

Degradation of the VISSR (Visible-Infrared Spin Scan Radiometer) visible sensor on the GMS-3 is estimated for a period from June 1987 to December 1988 by monitoring reflectances obtained from four targets on the earth. Samples of the highest brightness of midday cloud images and albedos observed over three desert target areas (the Great Sandy Desert, the Taklamakan Desert, and the Gobi Desert) are employed as targets. The results show that the brightness measured by the satellite sensor had appreciably deteriorated during the study period. The rate of degradation is estimated to be 5.3% per year from the analysis of the highest brightness, and 3.7%, 3.7% and 5.0% for the case of the Great Sandy Desert, the Taklamakan Desert, and the Gobi Desert, respectively. For the average of four cases, the estimated rate of degradation is 4.4% per year. -Authors