Biology
Scientific paper
Sep 1996
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996dps....28.0302p&link_type=abstract
American Astronomical Society, DPS meeting #28, #03.02; Bulletin of the American Astronomical Society, Vol. 28, p.1064
Biology
Scientific paper
The presence of liquid water during a given epoch is of tremendous importance to both climatology and exobiology. Under present climatic conditions, water at the surface of Mars is almost exclusively in a solid or adsorbed state. Yet orbiter images reveal channels, valley networks, and other geomorphic indicators of the past existence of liquid water. Recent dynamical calculations suggest that the obliquity of Mars, which is presently at an Earth-like 25.2 degrees, has ranged chaotically from 0 to as much as 60 degrees over the last 100 Myr, and is unpredictable over longer timescales. At high obliquities, not only will the polar regions continuously experience intense solar radiation during local spring and summer, but the water currently trapped as ice in the polar caps may get released as water vapor, potentially leading to a water vapor greenhouse heating effect. Thus the polar regions should be the first places on the planet that might experience temperatures that exceed 273K throughout an entire Martian day. Our modeling of the Martian surface heat balance at high latitudes and obliquities in the recent past (i.e., during the last 100 Myr) indicates that liquid water has indeed been stable in the polar regions of Mars during local spring and summer. Previously, both Toon et al. (1980) and Jakosky et al. (1995) modeled the high-obliquity climate of Mars, and both concluded that liquid water would not be stable at high obliquity. However, our model differs from these previous models in three crucial respects: a sophisticated Voigt quasi-random atmospheric radiative transfer model (Crisp, 1994) is employed to assess the water vapor greenhouse; the effects of atmospheric dust are incorporated; and perhaps most importantly, idealized sublimation into a completely dry atmosphere is not assumed. Using the best estimates of Martian polar surface properties such as thermal inertia and albedo, we present a detailed map of the "critical obliquity" required to sustain stable liquid water as a function of latitude and surface composition.
Paige David A.
Pathare Asmin
No associations
LandOfFree
Recent Liquid Water on Mars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Recent Liquid Water on Mars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Recent Liquid Water on Mars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1460761