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[15.20] Effects of surface dust on the sublimation of CO₂ on Mars. Radiative equilibrium atmospheric modeling.

B. P. Bonev, J. E. Bjorkman (University of Toledo), G. B. Hansen (Planetary Science Instutute), P. B. James (University of Toledo), M. J. Wolff (Space Science Institute)

Data from both the TES (Titus and Kieffer 2002, LPI, abs. 2071) and MOC (Bonev et al. 2002, GRL, in press) Mars Global Surveyor experiments have indicated a possible connection between the south polar cap regression rates and the global dust storm on Mars in 2001. These results were in qualitative agreement with our previous modeling of radiative transfer through a dusty atmosphere bounded by a sublimating CO₂ surface. The present work reports our subsequent modeling efforts focused in two important directions: 1) extension of the surface modeling by incorporating various effects on the frost albedo including variation in incidence angle, the ratio between diffuse and direct component of the incident radiation, variation in grain size of the CO₂ frost, and, most importantly, various amounts of surface intermixed dust. The last parameter is a major controlling factor on the albedo and consequently on the sublimation rate. Previously we have examined only the two limiting cases of "clean" and "very dirty" frost; 2) extension of the atmospheric modeling by our attempt to include (in addition to dust) the CO₂ 15 micron opacity in our radiative equilibrium scheme.

The purpose of these calculations is to better understand the root sensitivity of the CO₂ seasonal cycle on Mars to variations in atmospheric dust and surface dust intermixed with the frost.

This work has been supported by grants from the Mars Data Analysis Program.

If the author provided an email address or URL for general inquiries, it is as follows:

Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.