2003), Water mass conversion, fluxes and mixing in the Scotia Sea diagnosed by an inverse model

An inverse box model of the Scotia Sea is constructed using hydrographic, tracer, and velocity data collected along the rim of the basin during the Antarctic Large-Scale Box Analysis and the Role of the Scotia Sea (ALBATROSS) cruise. The model provides an estimate of the time-mean three-dimensional...

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Bibliographic Details
Main Authors: Alberto C. Naveira Garabato, David P. Stevens, Karen J. Heywood
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
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Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.516.31
http://www.noc.soton.ac.uk/soes/staff/acng/JPO_NGetal03.pdf
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Summary:An inverse box model of the Scotia Sea is constructed using hydrographic, tracer, and velocity data collected along the rim of the basin during the Antarctic Large-Scale Box Analysis and the Role of the Scotia Sea (ALBATROSS) cruise. The model provides an estimate of the time-mean three-dimensional circulation as the Antarctic Circumpolar Current (ACC) crosses the region. It concurrently solves for geostrophic and wind-driven Ekman transports across the boundaries of the basin, air–sea-driven diapycnal fluxes, and ‘‘interior’ ’ diapycnal fluxes below the ocean surface. An increase is diagnosed in the ACC volume transport from 143 6 13 Sv (Sv [ 106 m3 s21) at Drake Passage to 149 6 16 Sv on leaving the Scotia Sea, supplied by the import of 5.9 6 1.7 Sv of Weddell Sea Deep Water (WSDW) over the South Scotia Ridge. There is a lateral redistribution of the transport, primarily in response to a topographically induced branching of the 70–80 Sv polar front (PF) jet and an increase in the transport associated with the subantarctic front (SAF) from 31 6 7 to 48 6 4 Sv. A vertical rearrangement of the transport also occurs, with differences O(2 Sv) in the transports of intermediate and deep water masses. These volume transport changes are accompanied by a net reduction (increase) in the heat (freshwater) flux associated with the ACC by 0.02 6 0.020 PW (0.020 6 0.017 Sv), the main cause of which is the cooling and freshening of the Circumpolar Deep Water (CDW) layer in the Scotia Sea. The model