Bathymetric control of warm ocean water access along the East Antarctic Margin

Observed thinning of the Totten Glacier in East Antarctica has cast doubt upon the stability of the East Antarctic Ice Sheet. Recent oceanographic observations at the front of the Totten Ice Shelf have confirmed the presence of modified Circumpolar Deep Water (mCDW), which likely promotes enhanced m...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Nitsche, FO, Porter, D, Williams, G, Cougnon, EA, Fraser, AD, Correia, R, Guerrero, R
Format: Article in Journal/Newspaper
Language:English
Published: Amer Geophysical Union 2017
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Online Access:https://doi.org/10.1002/2017GL074433
http://ecite.utas.edu.au/122421
Description
Summary:Observed thinning of the Totten Glacier in East Antarctica has cast doubt upon the stability of the East Antarctic Ice Sheet. Recent oceanographic observations at the front of the Totten Ice Shelf have confirmed the presence of modified Circumpolar Deep Water (mCDW), which likely promotes enhanced melting. Details of how this water accesses the shelf remain uncertain. Here we present new bathymetry and autumnal oceanographic data from the outer continental shelf, north of the Totten Glacier, that show up to 0.7C mCDW in a>100km wide and >500m deep depression within the shelf break. In other parts of East Antarctica, a shelf break bathymetry shallower than 400m prevents these warmer waters from entering the shelf environment. Our observations demonstrate that detailed knowledge of the bathymetry is critical to correctly model the across-shelf exchange of warm water to the various glaciers/ice shelves of Antarctica for future sea level prediction.