Seminar Ozean, Eis, Atmosphäre

Date: 09.12.2003

Speaker: Dr. J. Wickert (GFZ Potsdam)

GPS (Global Positioning System) satellite signals are modified when traveling through the Earth's atmosphere. This fact can be used to derive accurate information on refractivity, temperature, and water vapor in the atmosphere.

An infrastructure for the use of GPS signals for remote sensing of the atmosphere was developed within the "Strategiefondsprojektes GASP". The high potential of the innovative GPS remote sensing method for a variety of applications within the weather forecast and atmospheric sciences were shown.

This talk will focus on satellite based remote sensing using GPS. The principles of radio occultation will be introduced. Profiles of refractivity, temperature, and water vapor are continuously retrieved from the radio occultation measurements of the German CHAMP (CHAllen-ging Minisatellite Payload) research satellite. There are about 200 vertical profiles up to an altitude of about 35 km available per day, globally distributed, independent of weather conditions.

An overview of the current results and an outlook of future satellite missions will be given. Other applications of the GPS remote sensing method will briefly be characterized (ground based water vapor determination, ionosphere sounding, measurement of reflexions).