HR: 0830h
AN: P51C-0456    [PDF]
TI: Numerical Simulation of Martian Global Dust Storms and the Dust Cycle
AU: * Basu, S
EM: shabari@gps.caltech.edu
AF: Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd, Pasadena, CA 91125 United States
AU: Richardson, M I
EM: mir@gps.caltech.edu
AF: Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd, Pasadena, CA 91125 United States
AU: Wilson, J
EM: rjw@gfdl.noaa.gov
AF: NOAA/Geophysical Fluid Dynamics Laboratory, P.O. Box 308, Princeton, NJ 08542 United States
AU: Ingersoll, A P
EM: api@gps.caltech.edu
AF: Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd, Pasadena, CA 91125 United States
AB: We investigate the triggering, growth, decay and the inter-annual variability of global dust storms (GDS) on Mars. To date, testing of various theories of GDS initiation and variability has been limited by inability to numerically simulate spontaneous, variable storm development from realistic pre-storm model states. Here we describe General Circulation Model simulations that generate spontaneous and variable GDSs from realistic background conditions. Modelled GDSs produce dramatic increases in atmospheric dustiness, global-mean air temperatures, and atmospheric circulation, in accord with observations. The simulations generate global storms in southern spring and summer with significant inter-annual variability in size and timing of occurrence, including years with no storms. We propose a simple explanation for the observed dust cycle on Mars from our simulations. Stresses associated with large-scale ($>$300 km) wind systems initiate the large storms. Explosive growth results from the intensification of the Hadley circulation and the activation of secondary dust lifting centers. Away from great storms, the annually repeatable cycle of atmospheric temperatures and dust opacities observed in northern spring and summer is a result of convective (dust devil) lifting.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 3319 General circulation
DE: 5409 Atmospheres--structure and dynamics
DE: 5445 Meteorology (3346)
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting