title: Dense waters of the Weddell and Scotia Seas: recent changes in properties and circulation.
abstract: The densest waters in the Atlantic overturning circulation are sourced at the periphery of Antarctica, especially the Weddell Sea, and flow northward via routes that involve crossing the complex bathymetry of the Scotia Arc. Recent observations of significant warming of these waters along much of the length of the Atlantic have highlighted the need to identify and understand the time-varying formation and export processes, and the controls on their properties and flows. Here, we review recent developments in understanding of the processes that control the changing flux of water through the main export route from the Weddell Sea into the Scotia Sea, and the transformations of the waters within the Scotia Sea and environs. We also present a synopsis of recent findings that relate to the climatic change of dense water properties within the Weddell Sea itself, in the context of known Atlantic-scale changes. Among the most significant findings are the discovery that the warming of waters exported from the Weddell Sea has been accompanied by a significant freshening, and that the episodic nature of the overflow into the Scotia Sea is markedly wind-controlled and can lead to significantly enhanced abyssal stratification. Key areas for focusing future research effort are outlined.
authors.affiliation: British Antarctic Survey, Cambridge CB3 0ET, UK Scottish Association for Marine Science, Oban PA37 1QA, UK mmm@bas.ac.uk.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Meredith
authors.affiliation: National Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UK.
authors.forename: Loïc
authors.initials: L
authors.lastname: Jullion
authors.affiliation: British Antarctic Survey, Cambridge CB3 0ET, UK School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Brown
authors.affiliation: National Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UK.
authors.forename: Alberto C
authors.initials: AC
authors.lastname: Naveira Garabato
authors.affiliation: National Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UK.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Couldrey
keywords: Antarctic Bottom Water; abyssal mixing; dense water export; overturning circulation