Atmos. Chem. Phys. Discuss., 8, 13775-13799, 2008
© Author(s) 2008. This work is distributed
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Water vapor transport in the lower mesosphere of the subtropics: a trajectory analysis
T. Flury, S. C. Müller, K. Hocke, and N. Kämpfer
Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland

Abstract. The Institute of Applied Physics operates an airborne microwave radiometer that measures the rotational transition line of water vapor at 183.3 GHz. Measurements were acquired on board a Learjet once a year in the period 1998 to 2006. Water vapor profiles are retrieved for the altitude range from 15 to 75 km along the flight track. We report on a water vapor enhancement in the lower mesosphere above India and the Arabic Sea measured on our flight mission in November 2005 conducted during EC-project SCOUT-O3. The flight led from Switzerland to Australia and back. We find an enhancement of up to 25% in the lower mesospheric H2O volume mixing ratio measured on the return flight one week after the outward flight. The origin of the air is traced back by means of a trajectory model in the lower mesosphere. During the outward flight the air came from the Carribean and crossed the Atlantic Ocean. On the return flight the air came from China and orginated from mid latitudes. Thus the large variability of H2O VMR during our flight is explained by a change of the winds in the lower mesosphere.

Citation: Flury, T., Müller, S. C., Hocke, K., and Kämpfer, N.: Water vapor transport in the lower mesosphere of the subtropics: a trajectory analysis, Atmos. Chem. Phys. Discuss., 8, 13775-13799, doi:10.5194/acpd-8-13775-2008, 2008.
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