HR: 1340h
AN: P13A-0142    [Abstracts]
TI: A Compressible Multiphase Model of Martian Dust Storms
AU: Linn, R
EM: rrl@lanl.gov
AF: Los Alamos National Lab, Los Alamos National Lab EES-2/MS D401, Los Alamos, NM 87507 United States
AU: * Reisner, J M
EM: rrl@lanl.gov
AF: Los Alamos National Lab, Los Alamos National Lab EES-2/MS D401, Los Alamos, NM 87507 United States
AB: Dust storms are ordinary events on Mars and occasionally these dust storms become big enough that they can encompass the entire planet. Not only can a global dust storm have a tremendous impact on the global circulation of Mars, but they also pose an extreme hazard for future explorations of the planet. However, little is known about how these large storms form and the mechanisms responsible for their growth. One possible mechanism for their growth is the formation of a particle-laden gravity current. A particle-laden gravity current is driven by negative buoyancy and opposed by turbulent mixing. As long as sufficient dust is present on the surface, the gravity current can be maintained indefinitely by entraining new dust particles from the surface. Furthermore, if significant compressional warming of the gas occurs at the leading edge of the dust storm, then the resulting positive buoyancy force could further enhance both the intensity and duration of a dust storm. Additionally, when a dust storm impacts a topographical feature on Mars, intensity changes will depend on the availability of surface dust over the feature and whether the dust storm is going up or down the topographical gradient. To investigate a dust storms response to changes in topography or compressional warming, a compressible multiphase model has been developed that solves mass, momentum, and energy equations for both the gas and for the solid dust particles in a generalized coordinate system. Results from the model strongly support the hypothesis that the compression of the gas at the leading edge of the dust storm, even for low wind speeds, could enhance a storm's intensity and duration.
DE: 5210 Planetary atmospheres, clouds, and hazes (0343)
SC: Planetary Sciences [P]
MN: Fall Meeting 2005