MODIS reflective solar bands calibration algorithm and on-orbit performance

The MODerate Resolution Imaging Spectroradiometer (MODIS)is one of the key instruments for the NASA s Earth Observing System (EOS).The MODIS ProtoFlight Model (PFM)was launched on-board the EOS Terra spacecraft on December 18,1999 and has been providing the science community and public users global data sets for the study of the land,oceans,and atmosphere for more than two and a half years.This coverage is further enhanced by the data sets from the MODIS Flight Model (FM-1)that was launched on-board the EOS Aqua spacecraft on May 4,2002.MODIS has 36 spectral bands with wavelengths ranging from 0.41 to 14.5 μm and nadir spatial resolutions of 250m (2 bands), 500m (5 bands),and 1km (29 bands).The sensor s 20 reflective solar bands (RSB)from 0.41 to 2.1 μm are calibrated on-orbit by a solar diffuser (SD)and a solar diffuser stability monitor (SDSM)system.The other 16 thermal emissive bands (TEB)with wavelengths above 3.7 μm are calibrated by a blackbody. This paper describes the RSB on-orbit calibration approach using the SD/SDSM system,its implementation in the Level 1B algorithm,and the RSB on-orbit characterization and performance for both Terra and Aqua MODIS. The TEB calibration algorithm and performance are presented in a separate paper in these proceedings.