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H.M. Böttger, S.R. Lewis, P.L. Read (AOPP), F. Forget (LMD)
Results from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) have long been the definitive data set for observations of the Martian water cycle. The ongoing Mars Global Surveyor Thermal Emission Spectrometer (TES) observations are providing new insights into the current water cycle, with detailed longitude-latitude dependence of water vapour with time, as well as information on vertical distribution of water vapour and ice cloud. Shown are the results of an ongoing project to model the current water cycle using the European Mars General Circulation Model (EMGCM), coupled with a semi-Lagrangian advection scheme. Parameterizations of water condensation/sublimation as well as a simple cloud scheme and a 10 layer regolith model have been added to the EMGCM suite of physics parameterizations in order to model the processes governing the current Martian water cycle. The EMGCM can be run with differing prescribed dust distributions resulting in different atmospheres due to the radiative effects of atmospheric dust particles. Results of simulations conducted using MGS-like dust scenarios as well as low-dust and dust-storm scenarios will be shown and compared to the available TES observations. A good spatial and in some cases quantitative comparison between observation and simulation, in terms of the zonally averaged and vertical distributions of both vapour and ice, can be found. In general, the TES observations are well reproduced. The MAWD observations are also well reproduced in the northern hemisphere, however, only significant adjustment of cloud parameters allows the MAWD southern hemisphere summer observations to be reproduced.
The author(s) of this abstract have provided an email address for comments about the abstract: bottger@atm.ox.ac.uk