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Accession Number N20120011111
Title Coupling Mars' Dust and Water Cycles: Effects on Dust Lifting Vigor, Spatial Extent and Seasonality.
Publication Date Mar 2012
Media Count 4p
Personal Author F. Montmessin J. L. Hollingsworth M. A. Kahre R. M. Haberle
Abstract The dust cycle is an important component of Mars' current climate system. Airborne dust affects the radiative balance of the atmosphere, thus greatly influencing the thermal and dynamical state of the atmosphere. Dust raising events on Mars occur at spatial scales ranging from meters to planet-wide. Although the occurrence and season of large regional and global dust storms are highly variable from one year to the next, there are many features of the dust cycle that occur year after year. Generally, a low-level dust haze is maintained during northern spring and summer, while elevated levels of atmospheric dust occur during northern autumn and winter. During years without global-scale dust storms, two peaks in total dust loading were observed by MGS/TES: one peak occurred before northern winter solstice at Ls 200-240, and one peak occurred after northern winter solstice at L(sub s) 305-340. These maxima in dust loading are thought to be associated with transient eddy activity in the northern hemisphere, which has been observed to maximize pre- and post-solstice. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading. Interactive dust cycle studies typically have not included the formation of water ice clouds or their radiative effects. Water ice clouds can influence the dust cycle by scavenging dust from atmosphere and by interacting with solar and infrared radiation, thereby modifying the thermal structure of the atmosphere and its circulation. Results presented in other papers at this workshop show that including the radiative effects of water ice clouds greatly influence the water cycle and the vigor of weather systems in both the northern and southern hemispheres.
Keywords Atmospheric circulation
Atmospheric general circulation mod
Dust storms
Hydrological cycle
Ice clouds
Mars atmosphere
Mars environment
Mars surface
Solar radiation

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 54 - Astronomy & Astrophysics
84B - Extraterrestial Exploration
55 - Atmospheric Sciences
Corporate Author National Aeronautics and Space Administration, Moffett Field, CA. Ames Research Center.
Document Type Conference proceedings
Title Note N/A
NTIS Issue Number 1301
Contract Number N/A

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