Seasonal variability of water masses and transport on the Antarctic continental shelf and slope in the southeastern Weddell Sea

Graham, Jennifer A.; Heywood, Karen J.; Chavanne, Cédric P.; Holland, Paul R. ORCID: https://orcid.org/0000-0001-8370-289X. 2013 Seasonal variability of water masses and transport on the Antarctic continental shelf and slope in the southeastern Weddell Sea. Journal of Geophysical Research: Oceans, 118 (4). 2201-2214. https://doi.org/10.1002/jgrc.20174

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Abstract/Summary

An array of five moorings was deployed from February 2009 to February 2010 across the Antarctic shelf and slope in the southeastern Weddell Sea (~18°W). Observations demonstrate the key processes responsible for variability in water masses and transport in the region. Rapid fluctuations in temperature and salinity throughout the year are linked with variability in wind stress over the array. This causes the deepening or shoaling of the pycnocline, past the depth of the moorings. In the upper 500 m, the seasonal cycle in salinity shows freshening in autumn, with the strongest freshening at the shallowest mooring (~250 m), furthest on-shelf. The sea ice concentration over the array exceeds 90% during this period and contributes a positive salt flux into the ocean during autumn. Freshening begins during strong along-shore (easterly) winds in late April 2009. This demonstrates that variations in Ekman transport and wind-driven mixing play a key role in determining the salinity of shelf waters around Antarctica. Transport of the Antarctic Slope Current also shows a seasonal cycle with a maximum during late April. Model simulations show the importance of along-shore advection, as the arrival of a fresh anomaly from upstream determines the timing of the salinity minimum at the array. These processes are likely to be important for other regions around the Antarctic continent

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1002/jgrc.20174
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Polar Oceans
ISSN:	21699275
Additional Keywords:	seasonal cycle, ocean-ice atmosphere interactions, Antarctic continental shelf, polar oceanography, Antarctic Slope Current
Date made live:	22 May 2013 10:35 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/502030

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