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Freshening drives contraction of Antarctic Bottom Water in the Australian Antarctic Basin


van Wijk, EM and Rintoul, SR, Freshening drives contraction of Antarctic Bottom Water in the Australian Antarctic Basin, Geophysical Research Letters, 41, (5) pp. 1657-1664. ISSN 0094-8276 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 American Geophysical Union

DOI: doi:10.1002/2013GL058921


Antarctic Bottom Water (AABW) in the Australian Antarctic Basin has become fresher and lighter since the late 1960s, with largest changes observed near the sources of AABW. The volume of AABW with neutral density (γn) > 28.30 kg m-3 decreased by ≥50% between 1969-1971 and 2008-2012, thinning at a rate of >100 m per decade. Contraction of dense AABW was balanced primarily by expansion of water lighter than γn = 28.15 kg m-3 prior to 1995 and by inflation of less dense classes of AABW after 1995. Oxygen concentrations remained unchanged in the densest AABW and increased on neutral surfaces for AABW with γn > 28.31 kg m-3, between 1995 and 2011-2012, consistent with continued ventilation over this time period. The observed changes in potential temperature, salinity, density, volume, and oxygen of AABW can be accounted for by freshening of the source waters but cannot be explained by changes in formation rate alone. Key Points Freshening drives contraction of Antarctic Bottom Water (AABW) AABW has contracted by about 50% and thinned more than 100 m per decade since 1970 Small increase in oxygen on isopycnals suggests continued ventilation of AABW ©2014. American Geophysical Union. All Rights Reserved.

Item Details

Item Type:Refereed Article
Keywords:Antarctic Bottom Water, Australian Antarctic Basin, freshening, water mass change, oxygen, density changes
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean oceanic processes
UTAS Author:Rintoul, SR (Dr Steve Rintoul)
ID Code:92515
Year Published:2014
Web of Science® Times Cited:65
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2014-06-21
Last Modified:2017-11-01

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