HR: 0830h
AN: P51C-0457    [PDF]
TI: Vortex Dust Flux: Experimental Results Comparing Terrestrial and Martian Cases
AU: * Neakrase, L D
EM: neakrase@asu.edu
AF: Arizona State University, Department of Geological Sciences Box 871404, Tempe, AZ 85287-1404 United States
AU: Greeley, R
EM: greeley@asu.edu
AF: Arizona State University, Department of Geological Sciences Box 871404, Tempe, AZ 85287-1404 United States
AU: Eddlemon, E
AF: Mars Surface Wind Tunnel Facility, NASA Ames Research Center Bldg. 242, Rm. 104, Moffet Field, CA 94305-1000 United States
AU: Iversen, J
AF: AEEM Department, Iowa State University 2271 Howe Hall, Rm. 1200, Ames, IA 50011-2271
AU: Balme, M
AF: Arizona State University, Department of Geological Sciences Box 871404, Tempe, AZ 85287-1404 United States
AU: Beardmore, G
AF: Arizona State University, Department of Geological Sciences Box 871404, Tempe, AZ 85287-1404 United States
AB: Evidence for active aeolian processes (dunes, windstreaks, ripples, dust storms, and dust devils) on Mars have been observed by Viking, Mars Global Surveyor (MGS), Mars Pathfinder (MPF), and Mars Odyssey. Dust devils on Mars, as on Earth, are seasonally dependent and are very common in some areas, leaving both bright and dark streaks in their wakes demonstrating their ability to modify the surface. Previously, experimental work demonstrated that the dust lifting mechanism, predominantly the pressure drop ($\Delta$P) in the dust devil core, is more efficient at lifting dust than boundary layer winds. The amount of dust that is lifted via the $\Delta$P-mechanism (dust flux) is not well understood for Earth or Mars. This study aims to develop that understanding through experiments with the Arizona State University Vortex Generator (ASUVG) at both Earth-ambient ($\sim$1000mb) and Mars ($\sim$10mb) conditions using physical analogs for martian dust (particles $\sim$2$\mu$m in diameter). The ASUVG generates dust-devil-like vortices through a motor-driven blade assembly positioned over a configurable test bed. Currently flux experiments have included a removable test plate that rests on an in situ balance used to measure the dust mass loss as a function of time for a $\sim$5mm-thick bed of dust settled by suspension. Preliminary results have given lower limits on dust devil dust flux for terrestrial ($\sim$1-2 g/m$^{2}$/s) and martian ($\sim$2-4 g/m$^{2}$/s) conditions. Martian conditions yield fluxes that are $\sim$1.5-2.0 times that of the analogous terrestrial cases. The terrestrial results are comparable to field observations made by Metzger (1999) in Eldorado Valley, NV, demonstrating the validity of using the ASUVG. Future studies intend the usage of optical systems to relate suspended dust opacity to mass in order to expand the range in sizes and speeds of vortices examined.
DE: 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707)
DE: 3332 Mesospheric dynamics
DE: 5409 Atmospheres--structure and dynamics
DE: 5415 Erosion and weathering
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting