Sensitivity Variation Of Aster Derived From Moon And Deepspace Observations In 2003 And 2017

ASTER, which is a multi-band pushbroom sensor onboard Terra, has provided worthful multiband images for approximately 20 years successfully since Terra's launch in 1999. For such a long operation, maintaining accurate radiometric calibration is an important challenge to guarantee the reliability of the satellite products. In April 2003 and August 2017, ASTER observed the Moon (and deepspace) for conducting radiometric calibration with the Moon, which is called as lunar calibration. Through the lunar calibration, temporal variation of relative sensor sensitivity can be measured accurately (the order of 0.1 %), which is reasonably accurate to improve calibration results from other methods. The lunar calibration was performed to ASTER's visible and near infrared bands (Band 1, Band 2, and Band 3N) by comparing the observed brightness with simulated lunar brightness. 3, 5, and 6% sensitivity degradation were observed in Band 1, Band 2, and Band 3N of ASTER, respectively, which are basically consistent with vicarious calibration, though still further discussion is needed for combining calibration results from different methods.