Dust dynamics inside Mars' polar caps

Supervision team: Axel Hagermann, Erika Kaufmann and Matt Balme

Lead contact: [email protected]

Description: The Martian polar ice caps exhibit a remarkable complexity in terms of variability and morphology. Using images from Mars Global Surveyor, the carbon dioxide features of Mars’ south polar cap display considerable variability (e.g. Malin et al., 2002, Titus et al., 2004). The resulting surface features have been dubbed as “spiders” (Piqueux et al., 2003), “swiss cheese” terrain (Thomas et al., 2000), the choice of words reflecting the degree of bewilderment in the face of these features. The underlying processes remain puzzling and perplexing and the source of much research and speculation. What is clear is that atmospheric dust plays a central role in the dynamics of the Martian ice caps.

Although solar energy density averaged over a year is the same at both poles, the two polar caps are distinctly different. While water ice deposits dominate Mars’ North Pole, its south pole has a CO2 ice cap. The temperature of the southern polar cap is controlled by its albedo, which is in turn controlled by dust on its surface (Paige and Ingersoll, 1985). Strangely, the albedo increases during the summer. Several self-cleansing mechanisms have been proposed for this phenomenon but none has been successfully simulated in the laboratory.

In this project, we plan to investigate the dynamics of Mars’ southern polar cap using the planetary ices simulation facility at The Open University’s Department of Physical Sciences. In this facility, we can recreate the conditions on Mars’ surface and observe the behaviour of CO2 ice. We will investigate the dynamics of an ice sample in a series of Martian artificial day/night cycles, simulating frost precipitation, dust deposition, surface and subsurface melting in situ. In the process we aim to understand the physics that leads to layering, texture and morphology changes and link these to dust and ice properties. The outcomes of the simulations will be used to construct a physical model of Mars’ transient south polar ice cap. We will then build a thermal mathematical model which can numerically simulate the processes that lead to the albedo changes observed in nature using the COMSOL Multiphysics software package.

The planetary ices simulation facility

Qualifications required: Suitable for Physics/Geophysics graduates with a first class or upper second class MSci/BSc degree.