Snow dune growth increases polar heat fluxes

Abstract:

Falling snow often accumulates in patches, dunes, or waves. These bedforms cover up to 13% of the surface of the Earth and appear occasionally on other planets. Their formation, however, is poorly understood.

Here, we use field observations to show that bedforms grow when snow falls in wind faster than a critical speed, which is (4.3 ± 0.9) m/s at our field site.

We quantify the effect of bedform growth on radiative and conductive heat fluxes through the snow, by simulating dune topographies using a numerical model, Rescal-snow. We show that if 10 cm of snow on sea ice is blown by a 9 m/s wind, it will collect into dunes that leave up to 56% of the ice surface exposed, and thereby absorb roughly double the solar energy that they would if the snow were flat.