On laboratory simulation and the effect of small temperature oscillations about the freezing point and ice formation on the evaporation rate of water on Mars

by Moore, S. R.; Sears, D. W. G.

We report measurements of the evaporation rate of water under Mars-like conditions (CO2 atmosphere at 7 mbar and similar to 0 degrees C) in which small temperature oscillations about the freezing point repeatedly formed and removed a thin layer of ice. We found that the average evaporation at 2.7 +/- 0.5 -> C without an ice layer (corrected for the difference in gravity on Earth and on Mars) was 1.24 +/- 0.12 mm/h, while at -2.1 +/- 0.3 degrees C with an ice layer the average evaporation rate was 0.84 +/- 0.08 mm/h. These values are in good agreement with those calculated for the evaporation of liquid water and ice when it is assumed that evaporation only depends on diffusion and buoyancy. Our findings suggest that such differences in evaporation rates are entirely due to the temperature difference and that the ice layer has little effect on evaporation rate. We infer that the formation of thin layers of ice on pools of water on Mars does not significantly increase the stability of water on the surface of Mars.

Journal
Astrobiology
Volume
6
Issue
4
Year
2006
Start Page
644-650
URL
https://dx.doi.org/10.1089/ast.2006.6.644
ISBN/ISSN
1557-8070; 1531-1074
DOI
10.1089/ast.2006.6.644