Radiometric performance of the CERES Earth radiation budget climate record sensors on the EOS Aqua and Terra spacecraft

Abstract

The CERES Flight Models 1 through 4 instruments were launched aboard NASA's Earth Observing System (EOS) Terra and Aqua Spacecraft into 705 Km sun-synchronous orbits with 10:30 a.m. and 1:30 p.m. equatorial crossing times. These instruments supplement measurements made by the CERES Proto Flight Model (PFM) instrument launched aboard NASA's Tropical Rainfall Measuring Mission (TRMM) spacecraft on November 27, 1997 into a 350 Km, 38-degree mid-inclined orbit. The archived CERES Science data products consist of geolocated and calibrated instantaneous filtered and unfiltered radiances through temporally and spatially averaged TOA, Surface, and Atmospheric fluxes. CERES filtered radiance measurements cover three spectral bands including shortwave (0.3 to 5 micron), total (0.3 to <100 micron) and an atmospheric window channel (8 to 12 micron). Earth Radiation Budget measurements made by the CERES represent a new era in radiation climate data. CERES climate data products realize a factor of 2 to 4 improvement in calibration accuracy and stability over the previous ERBE products. This improvement is derived from two sources: incorporation of lessons learned from the ERBE mission and the development of a rigorous and comprehensive radiometric validation protocol which consists of studies covering different spatial, spectral and temporal time scales on data collected both pre and post launch. This approach has resulted in unprecedented levels of accuracy for radiation budget data products with calibration stability of better than 0.2% and calibration traceability from ground to flight of 0.25%. The current work summarizes the status of the radiometric accuracy and stability of the CERES Edition2 Level 1 data products.