HR: 0800h
AN: P31C-0221    [Abstracts]
TI: Subsurface Ice on Mars with Rough Topography
AU: * Aharonson, O
EM: oa@caltech.edu
AF: California Institute of Technology, MC 150-21, Pasadena, CA 91125 United States
AU: Schorghofer, N
EM: norbert@hawaii.edu
AF: University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 United States
AB: High latitude ground ice on Mars may be explained, in part, by thermal stability and the abundance vapor in the Martian atmosphere. Local slopes alter surface and subsurface temperatures substantially, and hence allow ground ice to persist at locations where it would otherwise be unstable. Global statistics of the topography of Mars derived from MOLA are computed, processed, and extrapolated to derive a description of surface roughness on spatial scales to which ground ice should be sensitive. This slope distribution, with a global of Hurst exponent of approximately 0.81, is convolved with the predictions of a new thermal model for the dependence of subsurface ice on slope. We find that due to topographic slopes, ground ice can reside in locations where previous global models predict it to be unstable, down to latitudes of about 25 degrees in both hemispheres. This area includes, for example, the northern Olympus Mons aureole deposits, Hecates Tholus, and Hellas basin. In the highest latitudes slopes reduce the amount of buried ice, while in lower latitudes the ice fraction increases, smoothing the boundary of the ice table.
DE: 1823 Frozen ground
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: Fall Meeting 2005