Heidelberg 1999 – wissenschaftliches Programm
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UP: Umweltphysik
UP 11: Poster: Atmosphärenphysik und Physikalische Altersbestimmung
UP 11.3: Poster
Freitag, 19. März 1999, 12:45–14:30, KO
Retrieval of upper stratospheric and mesospheric temperature profiles from Millimeter–Wave Atmospheric Sounder data — •Axel von Engeln1,2, Stefan Bühler1, Klaus Künzi1, Tobias Wehr2, and Jörg Langen2 — 1University of Bremen, Institute of Remote Sensing, Kufsteiner Strasse, D 28359 Bremen, Germany — 2European Space Research and Technology Center, Postbus 299, 2200 AG Noordwijk zh, Netherlands
The Millimeter–Wave Atmospheric Sounder (MAS) is a shuttle–based instrument, observing the atmosphere in limb sounding geometry. Temperature information is derived from three oxygen lines near 60 GHz. Temperature profiles in the altitude range from 30 to 90 km can be measured. The data evaluation is done with the aid of an atmospheric radiative transfer model. Usually, the radiation is assumed to be unpolarized, so that spectral power is a scalar quantity. This assumption is not valid for oxygen lines that show Zeeman splitting in the Earth’s magnetic field. A more general form of the radiative transfer in which spectral power is represented by a vector has to be used in this case. The obtained information depends on the magnetic field. Using the MAS instrument characteristics, we investigate the possible temperature information that can be obtained from observation of polarized O2 emission lines with a spaceborne instrument. Synthetic retrievals show that the obtained accuracy of the retrieved temperature profile is below 3 K from 30 to 55 km and below 6 K for altitudes up to 90 km. The resolution is 4 km for altitudes of 30 to 50 km and 10 km above. The magnetic parameters influence the accuracy of the obtained profile by as much as 2 K. The obtained MAS temperature profiles were validated by a comparison to data from the Upper Atmosphere Research Satellite (UARS).