HR: 10:50h
AN: P32A-03    [Abstracts]
TI: MRO Accelerometer Experiment: Thermospheric Features Interpreted Using GCM Simulations
AU: * Bougher, S W
EM: bougher@umich.edu
AF: University of Michigan, AOSS Department, Ann Arbor, MI 48109, United States
AU: Keating, G M
EM: G.M.Keating@larc.nasa.gov
AF: George Washington University, (GWU), Hampton, VA 23681, United States
AU: Theriot, M E
EM: michael.e.theriot@nasa.gov
AF: George Washington University, (GWU), Hampton, VA 23681, United States
AU: Bell, J M
EM: jmbell@umich.edu
AF: University of Michigan, AOSS Department, Ann Arbor, MI 48109, United States
AU: Steers, B J
EM: brian.j.steers@gmail.com
AF: University of Michigan, AOSS Department, Ann Arbor, MI 48109, United States
AU: Murphy, J R
EM: murphy@nmsu.edu
AF: New Mexico State University, Department of Astronomy, Las Cruces, NM 88003, United States
AB: The MRO Accelerometer Experiment has recently measured upper atmospheric density and inferred temperatures in the southern hemisphere of Mars from 95 to 170 km during solar minimum conditions [e.g. Keating et al., 2006]. MRO began aerobraking in early martian southern Fall (Ls = 35) and continued for approximately 5-months with 450 aeropasses, ending in early southern winter (Ls = 109) near aphelion. This seasonal, latitude and solar local time sampling partially overlaps Mars Global Surveyor (MGS) sampling during Phase 2 aerobraking, when solar moderate conditions prevailed [Bougher et al., 2006]. Overall, data/model comparisons are very useful for understanding these MRO density and temperature datasets and placing them in the context of previous MGS Accelerometer measurements. Measured MRO latitudinal gradients in densities and inferred temperatures (at a constant altitude) will be compared with coupled MGCM-MTGCM model simulations in order to illustrate the role of the inter-hemispheric circulation in maintaining the observed density and temperature structure. Weak winter polar warming features for both MRO and MGS observing periods will be compared with each other (and with MGCM-MTGCM simulations), resulting in an initial characterization of weak inter-annual variations in this warming near aphelion. Finally, inferred MRO and MGS temperature profiles (including exospheric temperatures) will be compared with corresponding MGCM-MTGCM simulations. This comparison will contribute to an estimate of solar cycle variations of thermospheric temperatures near 70°S latitude for similar seasonal and solar local time conditions. Underlying thermal balances giving rise to these temperature variations will be extracted from MGCM-MTGCM simulations.
DE: 5405 Atmospheres (0343, 1060)
DE: 5445 Meteorology (3346)
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting