TITLE: The Orbital Theory of Ice Ages on Mars


ABSTRACT:
Norbert Schorghofer, Astrobiology Institute
University of Hawaii

Extensive ice reservoirs have been discovered on both hemispheres of
Mars, where ice exists beneath a thin (decimeter) layer of dry soil;
it was most recently explored by the Phoenix Lander.  Multiple
approaches have convincingly demonstrated that the subsurface ice
readily exchanges vapor with the atmosphere; small-scale physical
processes govern planetary-scale climate behavior.  These lessons can
be exploited to investigate how ice volume responds to orbital
variations, in analogy to the Milankovitch theory of Ice Ages on
Earth.  The emerging view of the history of ice on Mars is one where
significant volumes of ice are redistributed in response to orbital
forcing, and many ice ages have occurred in the past few million
years.  I will also describe a prototype of a globally balanced model
of the Martian water cycle, which will be the first climate model
capable of reproducing the Polar Layered Deposits.