HR: 0800h
AN: P11A-0966    [Abstracts]
TI: Representing Aerosols in Mars Climate Models
AU: * Montmessin, F
EM: fmontmessin@mail.arc.nasa.gov
AF: NASA Ames Research Center, Space Science Division, Moffett Field, CA 94035-1000 United States
AU: Colaprete, A
EM: tonyc@freeze.arc.nasa.gov
AF: NASA Ames Research Center, Space Science Division, Moffett Field, CA 94035-1000 United States
AU: Haberle, R M
AF: NASA Ames Research Center, Space Science Division, Moffett Field, CA 94035-1000 United States
AB: The study of aerosols is of prime importance for Mars Climate. Martian aerosols, a generic term for the airborne dust and the water ice crystals, and their related microphysical processes have a strong influence on the radiative budget and on the CO2 and the water cycles. For instance, previous studies have already stressed the necessity to understand how clouds and dust interact with each other and how eventually those interactions may lead to interannual climatic varability. Because aerosols are intimately tied to climatic issues, their study takes place in the context of General Circulation Model (GCM) simulations. Various treatments of microphysics have been introduced in Mars GCMs so far. Yet, it is still not known how these various schemes compare with each other. We have performed a suite of experiments using the NASA Ames General Circulation Model and several microphysical packages. This study aims at determining the most relevant formulation of mycrophysics for use in Mars climate models. Two criterions are considered: (i) the accuracy of each method and (ii) its computational cost. We show that dust and water ice clouds can be represented sufficiently by only two moments: mass and number. This simple formulation allows for fast computations, while remaining accurate enough with respect to more sophisticated schemes which suffer from prohibitive computational costs. However, we also show that using only one moment for a specific aerosol type, a method that has been widely employed within the community, results in a significant degradation of the predictions.
DE: 5407 Atmospheres--evolution
DE: 3367 Theoretical modeling
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting