Using Measurements of Aeolian Sand Transport to Ground-truth Martian Atmospheric Models

Abstract:

An understanding of the behavior of the Martian atmosphere is important for the success of any landed missions, but a lack of surface observations of Martian weather leaves models largely unconstrained. We present a timeseries of measurements of aeolian ripple migration acquired via automated image correlation at the Nili and Meroe Patera dune fields, located in a volcanic caldera complex in the equatorial Syrtis Major region, and show how this timeseries can be used to evaluate model predictions of Martian winds.

In particular, our measurements of ripple migration reveal a consistent seasonal increase in sand flux at the Nili and Meroe Patera dune fields in northern-hemisphere autumn and winter. This increase in sand flux is likely driven by a daytime upslope wind coming from the lower terrain to the east in the Isidis Basin. In atmospheric simulations from MarsWRF, in the cells closest to the dune fields, this pattern of seasonal sand flux change is not replicated, but it is better replicated in cells located just slightly further east. This implies that on Mars, the Isidis slope winds dominate over most of the area of the caldera, but in the model, they only dominate in the eastern half of the caldera. We hope that application of our techniques to more areas on Mars can bring additional insights and suggestions for improvement in models of the Martian atmosphere.