Meltwater produced by wind–albedo interaction stored in an East Antarctic ice shelf

Meltwater produced by wind–albedo interaction stored in an East Antarctic ice shelf

Lenaerts, JTM (Universiteit Utrecht; Katholieke Universiteit Leuven)
Lhermitte, S.L.M. (TU Delft Mathematical Geodesy and Positioning)
Drews, R. (Vrije Universiteit Brussel)
Ligtenberg, SRM (Universiteit Utrecht)
Berger, S. (Vrije Universiteit Brussel)
Helm, V. (Alfred Wegener Institute)
Smeets, C.J.P.P. (Universiteit Utrecht)
van den Broeke, MR (Universiteit Utrecht)
van de Berg, W.J. (Universiteit Utrecht)
van Meijgaard, E (Royal Netherlands Meteorological Institute (KNMI))
Eijkelboom, M. (Universiteit Utrecht)
Eisen, O. (Alfred Wegener Institute; University of Bremen)
Pattyn, F. (Vrije Universiteit Brussel)

2017

Surface melt and subsequent firn air depletion can ultimately lead to disintegration of Antarctic ice shelves1, 2 causing grounded glaciers to accelerate3 and sea level to rise. In the Antarctic Peninsula, foehn winds enhance melting near the grounding line4, which in the recent past has led to the disintegration of the most northerly ice shelves5, 6. Here, we provide observational and model evidence that this process also occurs over an East Antarctic ice shelf, where meltwater-induced firn air depletion is found in the grounding zone. Unlike the Antarctic Peninsula, where foehn events originate from episodic interaction of the circumpolar westerlies with the topography, in coastal East Antarctica high temperatures are caused by persistent katabatic winds originating from the ice sheet’s interior. Katabatic winds warm and mix the air as it flows downward and cause widespread snow erosion, explaining >3 K higher near-surface temperatures in summer and surface melt doubling in the grounding zone compared with its surroundings. Additionally, these winds expose blue ice and firn with lower surface albedo, further enhancing melt. The in situ observation of supraglacial flow and englacial storage of meltwater suggests that ice-shelf grounding zones in East Antarctica, like their Antarctic Peninsula counterparts, are vulnerable to hydrofracturing

Atmospheric science
Climate change
Cryospheric science

http://resolver.tudelft.nl/uuid:54dfb805-2a72-4572-af1f-c9d9dfaa1618

https://doi.org/10.1038/nclimate3180

2017-08-01

1758-678X

Nature Climate Change, 7, 58–62

Institutional Repository

journal article

© 2017 JTM Lenaerts, S.L.M. Lhermitte, R. Drews, SRM Ligtenberg, S. Berger, V. Helm, C.J.P.P. Smeets, MR van den Broeke, W.J. van de Berg, E van Meijgaard, M. Eijkelboom, O. Eisen, F. Pattyn