Publications

The German polar-orbiting satellite CHAMP (Challenging mini-satellite Payload) was successfully launched in mid-2000. Equipped with a space borne GPS (Global Positioning System) receiver provided by JPL (Jet Propulsion laboratory), CHAMP exploits the signals of the global network of GPS satellites for the remote sensing of temperature and humidity in the atmosphere. This new remote sensing technique provides globally distributed, calibration free and weather independent measurements with - thanks to its limb geometry - high vertical resolution. In contrast to the earlier US proof-of-concept mission GPS/MET, CHAMP exhibits improved technical characteristics of the instrument and aims at quasi-continuous operation. Since its first successful radio occultation sounding in February 2001, CHAMP collected more than 40000 individual profiles of temperature and tropospheric moisture. By now, several multi-week periods of continuous measurements are available for all seasons, each one providing up to 200 daily soundings. We present a validation study of this data set against operational meteorological analysis, the global radiosonde network, and retrievals obtained from the ATOVS family of instruments (AMSU-A, AMSU-B, and HIRS) on board NOAA-15 for both stratospheric temperatures and tropospheric moisture. The performance of the processing system for strongly disturbed atmospheric conditions like those during the stratospheric major warming events during the early winter 2001/2002 will be addressed.

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Marquardt, C.; Schöllhammer, K.; Schrödter, M.; Tomassini, M.; Beyerle, G.; Schmidt, T.; Wickert, J.; König, R.; Grunwaldt, L.; Reigber, C. (2002): Validation of 1 year of CHAMP radio occultation data. 27th General Assembly European Geophysical Society (EGS) (Nice 2002).