Circulation of modified Circumpolar Deep Water and basal melt beneath the Amery Ice Shelf, East Antarctica

Antarctic ice sheet mass loss has been linked to an increase in oceanic heat supply, which enhances basal melt and thinning of ice shelves. Here we detail the interaction of modified Circumpolar Deep Water (mCDW) with the Amery Ice Shelf, the largest ice shelf in East Antarctica, and provide the fir...

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Bibliographic Details
Published in:Journal of Geophysical Research: Oceans
Main Authors: Herraiz Borreguero, L, Coleman, R, Allison, I, Rintoul, SR, Craven, M, Williams, GD
Format: Article in Journal/Newspaper
Language:English
Published: Wiley-Blackwell Publishing, Inc. 2015
Subjects:
Earth Sciences
Oceanography
Physical Oceanography
Amery
Amery Ice Shelf
Antarctic
East Antarctica
Prydz Bay
Antarc*
Antarctica
Antarctica Journal
Ice Sheet
Ice Shelf
Ice Shelves
Online Access:https://doi.org/10.1002/2015JC010697
http://ecite.utas.edu.au/100449
Description
Summary:Antarctic ice sheet mass loss has been linked to an increase in oceanic heat supply, which enhances basal melt and thinning of ice shelves. Here we detail the interaction of modified Circumpolar Deep Water (mCDW) with the Amery Ice Shelf, the largest ice shelf in East Antarctica, and provide the first estimates of basal melting due to mCDW. We use subice shelf ocean observations from a borehole site (AM02) situated ∼70 km inshore of the ice shelf front, together with open ocean observations in Prydz Bay. We find that mCDW transport into the cavity is about 0.22 0.06 Sv (1 Sv = 10 6 m 3 s −1 ). The inflow of mCDW drives a net basal melt rate of up to 2 0.5 m yr −1 during 2001 (23.9 6.52 Gt yr −1 from under about 12,800 km 2 of the north-eastern flank of the ice shelf). The heat content flux by mCDW at AM02 shows high intra-annual variability (up to 40%). Our results suggest two main modes of subice shelf circulation and basal melt regimes: (1) the ice pump/high salinity shelf water circulation, on the western flank and (2) the mCDW meltwater-driven circulation in conjunction with the ice pump, on the eastern flank. These results highlight the sensitivity of the Amery's basal melting to changes in mCDW inflow. Improved understanding of such ice shelf-ocean interaction is crucial to refining projections of mass loss and associated sea level rise.

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