Aeolian Bedform Mobility on Earth and Mars

Project Description:

The transport of granular sediments by atmospheric flows and the associated development and migration of aeolian bedforms occurs on seven different planetary bodies in our solar system. Sand transport by wind is the dominant force shaping the contemporary surface of Mars and is yet poorly understood. Starting only recently have we been able to monitor the mobility of Martian dunes and ripples from high-resolution satellite imagery. Studies suggest that after an initial wind gust, sand particles can stay in motion at lower wind speeds for much longer than they would on Earth. However, sand transport is not homogenous across Mars, and the activity of dunes varies between hemispheres as well as between plateau v intra-crater environments, with varying seasonal and diurnal wind activity. These observations showcase the need for better understanding of transport thresholds, environmental conditions, and wind regimes that determine the mobility of dunes on Mars in comparison with Earth.

This project explores the processes and conditions determining dune mobility on Mars in comparison to those on Earth, using a variety of methods and a range of research questions, including:
– measuring changes in ripple orientation to infer local wind regimes (seasonal, unimodal, or bimodal wind regimes),
– monitoring dune migration rates and directions to compare with global atmospheric flow models,
– inferring sand transport thresholds from satellite imagery and numerical modelling,
– investigating conditions leading to relic footprints of periodic dune migration (dune casts), found on both Mars and Earth, using fieldwork, laboratory experiments, and modelling.

Policy Impact of Research:

The project reveals how changing climate may impact dune dynamics on planetary scale. Techniques developed for monitoring bedform activity on Mars are ideal for application to quantifying anthropogenic impacts on Earth over short time-scales. Understanding of sand transport conditions on Mars is important for future Mars mission targets and operations.

Research Relating to this Project:

1. The Bagnold Dunes in Southern Summer: Active Sediment Transport on Mars Observed by the Curiosity Rover
2. Dune Casts Preserved by Partial Burial: The First Identification of Ghost Dune Pits on Mars
3. Megaripple Migration on Mars