NERC-FAPESP’ Migrating dunes over hilly terrains

Granular materials are universal and all around us, from the devastating powers of a snow avalanche to the fabrication of medicines, and ground coffee beans to sand castles on the beach. Despite their prevalence in our daily lives, granular materials are hard to characterize and understand from a physical point of view. Dunes are manifestations of granular materials in the natural environment. Mobile hyper-arid desert dunes threaten the settlements and infrastructure of as many as one billion people worldwide. In order to protect communities and infrastructure from desertification in parts of the world that become dryer each year due to climate change, the dynamics of the evolution of a dune, from the growth of a bedform to the steady-state processes of a mature dune have to be understood.

This proposal focuses on a multifaceted approach to connect the avalanching processes at the grain level with the large-scale dune marching characteristics. The particular type of dune under investigation is a barchan dune, a fast-moving and crescentic-shaped dune present in unidirectional wind regimes with a limited sand supply. This collaborative project will investigate the effect of external landscape variations and topography on the speed and shape of these fast-moving dunes.