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Basal melt, seasonal water mass transformation, ocean current variability, and deep convection processes along the Amery Ice Shelf calving front, East Antarctica

Citation

Herraiz-Borreguero, L and Church, JA and Allison, I and Pena-Molino, B and Coleman, R and Tomczak, M and Craven, M, Basal melt, seasonal water mass transformation, ocean current variability, and deep convection processes along the Amery Ice Shelf calving front, East Antarctica, Journal of Geophysical Research: Oceans, 121, (7) pp. 4946-4965. ISSN 2169-9275 (2016) [Refereed Article]


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Copyright Statement

Copyright 2016 American Geophysical Union

DOI: doi:10.1002/2016JC011858

Abstract

Despite the Amery Ice Shelf (AIS) being the third largest ice shelf in Antarctica, the seasonal variability of the physical processes involved in the AIS-ocean interaction remains undocumented and a robust observational, oceanographic-based basal melt rate estimate has been lacking. Here we use year-long time series of water column temperature, salinity, and horizontal velocities measured along the ice shelf front from 2001 to 2002. Our results show strong zonal variations in the distribution of water masses along the ice shelf front: modified Circumpolar Deep Water (mCDW) arrives in the east, while in the west, Ice Shelf Water (ISW) and Dense Shelf Water (DSW) formed in the Mackenzie polynya dominate the water column. Baroclinic eddies, formed during winter deep convection (down to 1100 m), drive the inflow of DSW into the ice shelf cavity. Our net basal melt rate estimate is 57.4  25.3 Gt yr−1 (1  0.4 m yr−1), larger than previous modeling-based and glaciological-based estimates, and results from the inflow of DSW (0.52  0.38 Sv; 1 Sv = 106 m3 s−1) and mCDW (0.22  0.06 Sv) into the cavity. Our results highlight the role of the Mackenzie polynya in the seasonal exchange of water masses across the ice shelf front, and the role of the ISW in controlling the formation rate and thermohaline properties of DSW. These two processes directly impact on the ice shelf mass balance, and on the contribution of DSW/ISW to the formation of Antarctic Bottom Water.

Item Details

Item Type:Refereed Article
Keywords:Amery Ice Shelf, oceanography, ice shelf water, basal melt, ocean currents
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts)
Author:Herraiz-Borreguero, L (Dr Laura Herraiz Borreguero)
Author:Allison, I (Dr Ian Allison)
Author:Pena-Molino, B (Dr Beatriz Pena-Molino)
Author:Coleman, R (Professor Richard Coleman)
Author:Craven, M (Mr Mike Craven)
ID Code:111337
Year Published:2016
Funding Support:Australian Research Council (FT130100692)
Web of Science® Times Cited:2
Deposited By:Centre for Oceans and Cryosphere
Deposited On:2016-09-08
Last Modified:2017-02-01
Downloads:52 View Download Statistics

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