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M.A. Kahre, J.R. Murphy (New Mexico State University), R.M. Haberle, F. Montmessin, J. Schaeffer (NASA-Ames)
Interannual variability in the dust cycle on Mars is well documented but the mechanisms for this phenomenon are poorly understood. While the rapid radiative response time of the Martian atmosphere argues against hysteresis on annual timescales, the movement of dust in the system does enable hysteresis on the surface in the form of dust availibility, albedo changes, and altered surface roughness. In this work, we study the effect of including a finite ground dust source in dust cycle simulations with a general circulation model. We use the NASA Ames Mars General Circulation Model (GCM) to simulate the dust cycle on Mars. In our fully interactive model, we include dust lifting due to winds and dust devils and radiatively active dust transport. Multiple particle sizes are included, ranging from 0.1 to 20 microns, and we keep track of the locations of these particles both in the atmosphere and on the ground. We initialize the surface dust distribution using TES albedo maps as a guide. Regions of very low albedo have no surface dust initially; higher albedo regions have progressively greater quantities of available surface dust. We present preliminary results of a multiple year simulation with a finite dust source, and we compare these results to simulations that include an infinite dust source. This project is funded by the NASA Graduate Student Researchers Program and the NASA Planetary Atmospheres Program (NAG5-12123)
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.