Dynamical paleoclimatology of Mars

Citation

Soto, Alejandro (2012) Dynamical paleoclimatology of Mars. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:01252012-143955675

Abstract

We investigated the dynamical paleoclimatology of Mars with a focus on three areas: large scale dynamics, atmospheric collapse, and controls on precipitation and aridity of a warm, wet Mars. We explored the changes, and lack of changes, in the large scale circulation over a range of atmospheric masses. We present the results here, with an emphasis on the response of the winds and the meridional transport.

The conditions for continuous condensation of the CO2 atmospheres in the polar re- gions, often called ’atmospheric collapse’, were explored by simulating the Martian atmo- sphere over a wide range of obliquities for a wide range of atmospheric thicknesses. As expected, atmospheric collapse occurs at low obliquities, but surprisingly, collapse occurs for high obliquities (up to 40◦) for moderate atmospheric thicknesses (100’s of millibars up to 1000 millibars). Using the MarsWRF model, we show that a competition between atmospheric heating feedbacks, including the greenhouse feedback and the heat transport feedback, and the condensation temperature feedback determines whether atmosphere col- lapse occurs.

Finally, we explored the precipitation and aridity of a warm, wet Mars with an active hydrological system. Even an extremely wet climate with a northern hemisphere ocean produces an extremely dry, desert climate in the southern hemisphere, with an equatorial band of rain and run off. Cross-equatorial flows deliver moist air from the northern ocean into the southern region, but topography and the distribution of land versus ocean limit the extent of the rainfall.

Thesis Files