Midterm colloquium by Louise Steffensen Schmidt – Niels Bohr Institute - University of Copenhagen

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Midterm colloquium by Louise Steffensen Schmidt

Estimating the thickness of ice deposits at Martian mid-latitudes

High resolution images of the surface of Mars have shown that several
types of martian deposits in the 30-55 deg. latitude band have detailed
flow patterns consistent with the flow of ice. In addition, radar
properties of the deposits strongly suggest that they consist of
nearly-pure near-surface water ice [Carr and Head, 2009]. It is believed
that the deposits are remnants from a previous 'ice age' which have
survived under a thin layer of dust, which has protected the underlying
ice from sublimation for millions of years [Head et al., 2003].

In order to estimate the amount of ice in one or more selected areas,
the ice thickness will be estimated by interpolating under the ice using
a polynomial method. The interpolated bed elevation is then compared to
available SHARAD radargrams from NASA's Mars Reconnaissance Orbiter to
estimate the uncertainty of the method.

The bed topography will also be estimated using two 2D flow models; the
first is based on the perfect plasticity approximation and the second is
a more general model based on Glen's flow law. The unknown model
parameters in each model will be estimated using a Monte Carlo inverse
algoritm, which compares the modelled bed elevation to the interpolated
elevation. This method will provide information about the flow
properties of the ice, like e.g. the temperature and the creep exponent.