nai

Project Progress

In recent years in has become apparent that ice ages occurred on Mars. One dynamic ice reservoirs lies beneath Mars’ dry surface, buried by a thin layer of dry soil. This subsurface ice was mapped out by the Gamma Ray Spectrometer Suite and is now being explored by the Phoenix Lander. In a continuing research project, these ice layers, stretching from about 60 degree latitude to the Polar Layered Deposits, are being investigated further.

A numerical model of subsurface vapor transport has been further developed that will ultimately lead to a new generation of Global Mars Climate Models. An overall discussion of this issue can be found in N. Schorghofer, The role of subsurface-atmosphere exchange in climate history and climate models of Mars, Abstract for the Mars Water Cycle Workshop, Paris (2008).

As our understanding of the distribution of ice on Mars progresses, we can take a new look at how this ice moves around in response to Milankovitch forcing. The extent of subsurface ice is controlled by surface temperature and atmospheric humidity. Work in progress shows that the surface temperature at the margins of the ice layers is mainly controlled by the precession cycle, which is otherwise much weaker than the obliquity cycle.

In collaboration with B. Diez and others, the first detailed comparison between measured and predicted H₂O burial depth was carried out, see the paper by B. Diez et al., H layering in the top meter of Mars, Icarus 196, 409-421 (2008).