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L. Montabone, S. R. Lewis, P. L. Read (AOPP, Dept. of Physics, University of Oxford, UK)
We study the inter-annual variability of dust storms on Mars in an assimilation of thermal profiles and dust opacity observations into a general circulation model for the Martian atmosphere. The observations have been provided by the Thermal Emission Spectrometer aboard the Mars Global Surveyor spacecraft during the scientific mapping phase over more than two complete Martian years, which include three dusty seasons in southern spring time. The model into which observations have been assimilated is the Oxford (spectral) version of the European Mars General Circulation Model (Forget et al., 1999; J. Geophys. Res. 104, 24,155-24,176). Data assimilation offers a unique opportunity to study the inter-annual variability of the dust cycle and dust storms and their effects on the global circulation, as it provides a complete, balanced, four-dimensional best-fit to observations for all the atmospheric variables, including those for which no direct measurements are available, such as zonal and meridional winds. This work presents a comparison between dust seasons which are characterized only by regional storms and the global, planet-encircling dust storm of 2001. We focus on the meteorological conditions which can trigger the onset and development of a global dust storm, and the storm's effects on the global circulation. In particular, we examine the role of near-surface wind stress and dust devils in the processes which gave rise to the expansion to global scale of the initial regional dust storm around the slopes of Hellas basin in 2001.
This work was supported by the UK Particle Physics and Astronomy Research Council
The author(s) of this abstract have provided an email address for comments about the abstract: montabone@atm.ox.ac.uk
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.