Solitary wave behavior in sand dunes observed from space

Abstract

[1] Although the dynamics of individual barchan dunes are well understood, their interactions are the subject of ongoing scientific interest and debate. Numerical and analog model predictions of shape-preserving binary dune collisions have been hard to test due to the long timescales over which such processes typically occur. This paper documents ten binary dune collisions in a 45-year time sequence of satellite images from the Bodele Depression in Chad. The observations confirm that when two barchan dunes collide, a transfer of mass occurs so that one dune appears to travel through the other unscathed, like a solitary wave.