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Antarctic Ice Shelf Potentially Stabilized by Export of Meltwater in Surface RiverMeltwater stored in ponds and crevasses can weaken and fracture ice shelves, triggering their rapid disintegration. This ice-shelf collapse results in an increased flux of ice from adjacent glaciers and ice streams, thereby raising sea level globally. However, surface rivers forming on ice shelves could potentially export stored meltwater and prevent its destructive effects. Here we present evidence for persistent active drainage networks-interconnected streams, ponds and rivers-on the Nansen Ice Shelf in Antarctica that export a large fraction of the ice shelf's meltwater into the ocean. We find that active drainage has exported water off the ice surface through waterfalls and dolines for more than a century. The surface river terminates in a 130-metre-wide waterfall that can export the entire annual surface melt over the course of seven days. During warmer melt seasons, these drainage networks adapt to changing environmental conditions by remaining active for longer and exporting more water. Similar networks are present on the ice shelf in front of Petermann Glacier, Greenland, but other systems, such as on the Larsen C and Amery Ice Shelves, retain surface water at present. The underlying reasons for export versus retention remain unclear. Nonetheless our results suggest that, in a future warming climate, surface rivers could export melt off the large ice shelves surrounding Antarctica-contrary to present Antarctic ice-sheet models, which assume that meltwater is stored on the ice surface where it triggers ice-shelf disintegration.
Document ID
20170006594
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Bell, Robin E. (Columbia Univ. Palisades, NY, United States)
Chu, Winnie (Columbia Univ. Palisades, NY, United States)
Kingslake, Jonathan (Columbia Univ. Palisades, NY, United States)
Das, Indrani (Columbia Univ. Palisades, NY, United States)
Tedesco, Marco (Columbia Univ. Palisades, NY, United States)
Tinto, Kirsty J. (Columbia Univ. Palisades, NY, United States)
Zappa, Christopher J. (Columbia Univ. Palisades, NY, United States)
Frezzotti, Massimo (Italian National Agency for New Technologies, Energy and the Environment (ENEA) Rome, Italy)
Boghosian, Alexandra (Columbia Univ. Palisades, NY, United States)
Lee, Won Sang (Korean Polar Research Institute Incheon, Korea, Republic of)
Date Acquired
July 17, 2017
Publication Date
April 19, 2017
Publication Information
Publication: Nature
Volume: 544
Issue: 7650
ISSN: 0028-0836
Subject Category
Meteorology and Climatology
Numerical Analysis
Earth Resources and Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN42703
Funding Number(s)
CONTRACT_GRANT: DGE-16-44869
CONTRACT_GRANT: NNX15AN28H
CONTRACT_GRANT: NNX14AH79G
CONTRACT_GRANT: NSF 1341688
CONTRACT_GRANT: NSF Rosetta 1443534
CONTRACT_GRANT: NNX16AJ65G
Distribution Limits
Public
Copyright
Other