MODIS and VIIRS On-orbit Calibration and Characterization Using Observations from Spacecraft Pitch Maneuvers

摘要

Two MODIS instruments (Terra and Aqua) and two VIIRS instruments (S-NPP and JPSS-1) are currently operated in space, continuously making global earth observations in the spectral range from visible (VIS) to long-wave infrared (LWIR). These observations have enabled a broad range of environmental data records to be generated and distributed in support of both operational and scientific community. Despite extensive pre-launch calibration and characterization performed for both MODIS and VIIRS instruments and routine on-orbit calibration activities carried out using their onboard calibrators (OBC), various spacecraft maneuvers have also been designed and implemented to further enhance the sensor on-orbit calibration and data quality. This paper focuses on the use of observations made during spacecraft pitch maneuvers of MODIS and VIIRS in support of their on-orbit characterization of thermal emissive bands (TEB) response versus scan-angle (RVS). In the case of Terra MODIS. lunar observations made from instrument nadir view during spacecraft pitch maneuvers are used to compare with that made regularly through instrument space view (SV) port to evaluate on-orbit changes in RVS and band-to-band registration (BBR) for the reflective solar bands (RSB). In addition to results derived from spacecraft pitch maneuvers performed for MODIS and VIIRS, discussion is provided on the advantages, challenges, and lessons for future considerations and improvements.