West Antarctic surface melt triggered by atmospheric rivers

• Published in: Nature Geoscience
• Main Authors: Wille, Jonathan D., Favier, Vincent, Dufour, Ambrose, Gorodetskaya, Irina V., Turner, John, Agosta, Cecile, Codron, Francis
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Nature Research 2019
• Subjects: Antarctic; Byrd; Marie Byrd Land; Ross Ice Shelf; West Antarctic Ice Sheet; West Antarctica; Wilkins; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: http://nora.nerc.ac.uk/id/eprint/525774/; https://www.nature.com/articles/s41561-019-0460-1

Recent major melting events in West Antarctica have raised concerns about a potential hydrofracturing and ice shelf instability. These events often share common forcings of surface melt-like anomalous radiative fluxes, turbulent heat fluxes and föhn winds. Using an atmospheric river detection algorithm developed for Antarctica together with surface melt datasets, we produced a climatology of atmospheric river-related surface melting around Antarctica and show that atmospheric rivers are associated with a large percentage of these surface melt events. Despite their rarity (around 12 events per year in West Antarctica), atmospheric rivers are associated with around 40% of the total summer meltwater generated across the Ross Ice Shelf to nearly 100% in the higher elevation Marie Byrd Land and 40–80% of the total winter meltwater generated on the Wilkins, Bach, George IV and Larsen B and C ice shelves. These events were all related to high-pressure blocking ridges that directed anomalous poleward moisture transport towards the continent. Major melt events in the West Antarctic Ice Sheet only occur about a couple times per decade, but a 1–2 °C warming and continued increase in atmospheric river activity could increase the melt frequency with consequences for ice shelf stability.