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Coastal freshening enhances eddy-driven heat transfer toward the Antarctic margins
  • Yidongfang Si,
  • Andrew Stewart,
  • Ian Eisenman
Yidongfang Si
Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles

Corresponding Author:[email protected]

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Andrew Stewart
Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles
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Ian Eisenman
Scripps Institution of Oceanography, University of California, San Diego
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The Antarctic Slope Front (ASF) is a strong gradient in water mass properties close to the Antarctic margins. Heat transport across the ASF is important to Earth’s climate, as it influences melting of ice shelves, the formation of bottom water, and thus the global meridional overturning circulation. Previous studies based on relatively low-resolution models have reported contradictory findings regarding the impact of additional meltwater on onshore heat transport onto the Antarctic continental shelf: it remains unclear whether meltwater enhances shoreward heat transport, leading to a positive feedback, or further isolates the continental shelf from the open ocean. In this study, heat transport across the ASF is investigated using high-resolution, process-oriented simulations. It is found that shoreward heat transport is primarily controlled by the salinity gradient of the shelf waters: both freshening and salinification of the shelf waters relative to the offshore waters lead to increased heat flux onto the continental shelf. For salty shelves, the overturning consists of a dense water outflow that drives a shoreward heat flux near the seafloor; for fresh shelves, there is a shallow, eddy-driven overturning circulation that is associated with an export of fresh surface waters and a near-surface shoreward heat flux. The eddy-driven overturning associated with coastal freshening may lead to a positive feedback in a warming climate: large volumes of meltwater increase shoreward heat transport, causing further melt of ice shelves.
03 May 2023Published in Science Advances volume 9 issue 18. https://doi.org/10.1126/sciadv.add7049