The freshwater system west of the Antarctic Peninsula: spatial and temporal changes

Meredith, Michael P. ORCID: https://orcid.org/0000-0002-7342-7756; Venables, Hugh J. ORCID: https://orcid.org/0000-0002-6445-8462; Clarke, Andrew ORCID: https://orcid.org/0000-0002-7582-3074; Ducklow, Hugh W.; Erickson, Matthew; Leng, Melanie J. ORCID: https://orcid.org/0000-0003-1115-5166; Lenaerts, Jan T. M.; van den Broeke, Michiel R.. 2013 The freshwater system west of the Antarctic Peninsula: spatial and temporal changes. Journal of Climate, 26 (5). 1669-1684. https://doi.org/10.1175/JCLI-D-12-00246.1

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Text © Copyright 2013 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or copyright@ametsoc.org. jcli-d-12-00246.1.pdf - Published Version Download (2MB) | Preview

Abstract/Summary

Climate change west of the Antarctic Peninsula is the most rapid of anywhere in the Southern Hemisphere, with associated changes in the rates and distributions of freshwater inputs to the ocean. Here, results from the first comprehensive survey of oxygen isotopes in seawater in this region are used to quantify spatial patterns of meteoric water (glacial discharge and precipitation) separately from sea ice melt. High levels of meteoric water are found close to the coast, due to orographic effects on precipitation and strong glacial discharge. Concentrations decrease offshore, driving significant southward geostrophic flows (up to ~30 cm s−1). These produce high meteoric water concentrations at the southern end of the sampling grid, where collapse of the Wilkins Ice Shelf may also have contributed. Sea ice melt concentrations are lower than meteoric water and patchier because of the mobile nature of the sea ice itself. Nonetheless, net sea ice production in the northern part of the sampling grid is inferred; combined with net sea ice melt in the south, this indicates an overall southward ice motion. The survey is contextualized temporally using a decade-long series of isotope data from a coastal Antarctic Peninsula site. This shows a temporal decline in meteoric water in the upper ocean, contrary to expectations based on increasing precipitation and accelerating deglaciation. This is driven by the increasing occurrence of deeper winter mixed layers and has potential implications for concentrations of trace metals supplied to the euphotic zone by glacial discharge. As the regional freshwater system evolves, the continuing isotope monitoring described here will elucidate the ongoing impacts on climate and the ecosystem.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1175/JCLI-D-12-00246.1
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Polar Oceans
ISSN:	0894-8755
Additional Keywords:	Southern Ocean, ocean circulation, freshwater, precipitation, snowmelt/icemelt, isotopic analysis
Date made live:	25 Apr 2013 10:57 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/501487

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