Dresden 2020 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 28: Pattern Formation and Reaction-Diffusion Systems
DY 28.8: Talk
Tuesday, March 17, 2020, 12:00–12:15, ZEU 147
Salt polygons are caused by convection — •Lucas Goehring1, Jana Lasser2, Marcel Ernst2, and Joanna Nield3 — 1Nottingham Trent University — 2Max Planck Institute for Dynamics and Self-Organisation — 3University of Southampton
From fairy circles to patterned ground and columnar joints, natural patterns spontaneously appear in many complex geophysical settings. Here, we shed light on the origins of polygonally patterned crusts of salt playa and salt pans. These beautifully regular features, approximately a meter in diameter, are found worldwide and are fundamentally important to the transport of salt and dust in arid regions. We show that they are consistent with the surface expression of buoyancy-driven convection in the porous soil beneath a salt crust. By combining quantitative results from direct field observations, analogue experiments, linear stability theory, and numerical simulations, we further determine the conditions under which salt polygons should form, as well as how their characteristic size emerges.