MODIS TEB calibration approach in collection 6

Abstract

The MODerate Resolution Imaging Spectroradiometer (MODIS) is a heritage sensor operating on both the Terra and Aqua platforms, and has collected remotely sensed data for a combined mission time of twenty plus years. The instrument robustness and performance over their lifetimes has been very satisfactory and is well calibrated using the onboard calibrators (OBC). The radiometric fidelity of the MODIS instruments has ensured the high quality of science products derived from the Level 1B (L1B) imagery. MODIS Thermal Emissive Bands (TEB) are calibrated on-orbit using an on-board blackbody (BB) and through the space-view (SV) port. The MODIS BB is nominally controlled at 290K for Terra and at 285K for Aqua. Periodically, a BB warm-up and cool-down (WUCD) process is implemented, during which the BB temperatures vary from instrument ambient (approximately 272K) to 315K. The calibration coefficients for the 16 TEB bands are characterized using the above mentioned on-board BB operations (i.e. using nominal and WUCD operations). This paper will focus on the calibration algorithms of the TEB developed for collection 6 (C6) processing, its impact on the Level 1B (L1B) product in comparison to collection 5 (C5), and the methodology for issuing a Look Up Table (LUT) update for L1B processing.