HR: 0800h
AN: P11A-0246    [Abstracts]
TI: Investigation of Gravity Wave Propagation in the Martian Atmosphere.
AU: * Parish, H F
EM: helen@atmos.ucla.edu
AF: University of California Los Angeles, Inst. Geophys. and Planetary Phys. 603 Charles E. Young Drive, Los Angeles, CA 90095-1567, United States
AU: Schubert, G
EM: schubert@ucla.edu
AF: University of California Los Angeles, Inst. Geophys. and Planetary Phys. 603 Charles E. Young Drive, Los Angeles, CA 90095-1567, United States
AU: Hickey, M
EM: michael.hickey@erau.edu
AF: Embry-Riddle Aeronautical Univ., Dept Phys. Sci. 600 S Clyde-Morris Blvd, Daytona Beach, FL 32114, United States
AB: Periodic atmospheric variations with the characteristics of gravity waves have been detected in the Martian atmosphere since the early measurements from Viking and Mariner 9. More recent temperature and aerobraking data from Mars Global Surveyor (MGS), and Mars Odyssey (ODY) suggest the presence of lee waves in ice clouds near the Martian surface, and show fluctuations in the thermospheric density with periods and wavelengths typical of gravity waves. Gravity waves are believed to have important effects in the Earth's atmosphere, producing fluctuations in the density, temperature, winds, and airglow intensities in the mesosphere and lower thermosphere, and generating a reversal of the summer to winter temperature gradient, which produces winter warming near the mesopause. If gravity waves are regularly present in the Martian atmosphere, they may also have significant effects on the circulation and energy budget. The effects of sub-grid scale gravity wave processes are generally represented in atmospheric models through a number of parameterization schemes. However, in this work, we determine the propagation of realistic individual gravity waves in the Martian atmosphere, using a linearized one-dimensional full-wave model. Calculations have been performed using atmospheric parameters based on observations of apparent lee waves in high latitude clouds, measured by the MOLA instrument aboard MGS. The results show that some of the generated lee waves are capable of propagating up into the Martian thermosphere. Wave propagation is found to be sensitive to the properties of the background atmosphere, including the wind and temperature structure. Waves which reach the thermosphere produce fluctuations in density with characteristics consistent with those of the density variations detected in ODY aerobraking data. The presence of critical levels and the temperature profile of the Martian atmosphere are found to determine the wavelengths, periods, and direction of propagation of the waves that are able to propagate up to the thermosphere. Gravity waves of modest amplitude are found to deposit momentum and generate significant heating and cooling in the Martian atmosphere.
DE: 3319 General circulation (1223)
DE: 3384 Acoustic-gravity waves
DE: 5405 Atmospheres (0343, 1060)
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting