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Sensitivity of Antarctic bottom water to changes in surface buoyancy fluxes


Snow, K and Hogg, AMcC and Sloyan, BM and Downes, SM, Sensitivity of Antarctic bottom water to changes in surface buoyancy fluxes, Journal of Climate, 29, (1) pp. 313-330. ISSN 0894-8755 (2016) [Refereed Article]


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DOI: doi:10.1175/JCLI-D-15-0467.1


The influence of freshwater and heat flux changes on Antarctic Bottom Water (AABW) properties are investigated within a realistic bathymetry coupled ocean–ice sector model of the Atlantic Ocean. The model simulations are conducted at eddy-permitting resolution where dense shelf water production dominates over open ocean convection in forming AABW. Freshwater and heat flux perturbations are applied independently and have contradictory surface responses, with increased upper-ocean temperature and reduced ice formation under heating and the opposite under increased freshwater fluxes. AABW transport into the abyssal ocean reduces under both flux changes, with the reduction in transport being proportional to the net buoyancy flux anomaly south of 60°S.

Through inclusion of shelf-sourced AABW, a process absent from most current generation climate models, cooling and freshening of dense source water is facilitated via reduced on-shelf/off-shelf exchange flow. Such cooling is propagated to the abyssal ocean, while compensating warming in the deep ocean under heating introduces a decadal-scale variability of the abyssal water masses. This study emphasizes the fundamental role buoyancy plays in controlling AABW, as well as the importance of the inclusion of shelf-sourced AABW within climate models in order to attain the complete spectrum of possible climate change responses.

Item Details

Item Type:Refereed Article
Keywords:Antarctic Bottom Water, AABW
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical oceanography
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Climate variability (excl. social impacts)
UTAS Author:Downes, SM (Dr Stephanie Downes)
ID Code:109410
Year Published:2016
Web of Science® Times Cited:21
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2016-06-14
Last Modified:2017-11-01
Downloads:210 View Download Statistics

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