Abstract

This paper gives an overview of the COSMIC Data Analysis and Archival Center (CDAAC) and presents initial results that were obtained from neutral atmospheric radio occultation data processing of the GPS/MET, CHAMP, and SAC-C datasets. Approximately 45 % of CHAMP and SAC-C retrieved radio occultat... Show moreThis paper gives an overview of the COSMIC Data Analysis and Archival Center (CDAAC) and presents initial results that were obtained from neutral atmospheric radio occultation data processing of the GPS/MET, CHAMP, and SAC-C datasets. Approximately 45 % of CHAMP and SAC-C retrieved radio occultation profiles reach below 1 km altitude, compared to only 35 % for GPS/MET. All missions exhibit a negative refractivity bias in the lower troposphere of nearly 1 % compared to NWP models. When constrained to the tropics, the CHAMP data show a negative refractivity bias of approximately 1.7 %, and only 20 % of occultation profiles reach 1 km. Current CDAAC LEO orbit determination for CHAMP agrees with JPL orbits at the 30 cm 3D root mean square level, which can result in temperature errors of about 0.3 degrees K at 30 km altitude. Show less