The freshwater system west of the Antarctic Peninsula : spatial and temporal changes
Meredith, Michael P.
Venables, Hugh J.
Ducklow, Hugh W.
Leng, Melanie J.
Lenaerts, Jan T. M.
van den Broeke, Michiel R.
MetadataShow full item record
KeywordSouthern Ocean; Ocean circulation; Freshwater; Precipitation; Snowmelt/icemelt; Isotopic analysis
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.
Author Posting. © American Meteorological Society, 2013. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 26 (2013): 1669–1684, doi:10.1175/JCLI-D-12-00246.1.
Showing items related by title, author, creator and subject.
Macdonald, Alison M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1995-08)Data from fifteen globally distributed, modern, high resolution, hydrographic oceanic transects are combined in an inverse calculation using large scale box models. The models provide estimates of the global meridional ...
Rabe, Benjamin; Karcher, Michael; Schauer, Ursula; Toole, John M.; Krishfield, Richard A.; Pisarev, Sergey; Kauker, Frank; Gerdes, Rudiger; Kikuchi, Takashi (2010-12-10)Unprecedented summer-season sampling of the Arctic Ocean during the period 2006−2008 makes possible a quasi-synoptic estimate of liquid freshwater (LFW) inventories in the Arctic Ocean basins. In comparison to observations ...
Ganachaud, Alexandre S. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1999-12)A new, global inversion is used to estimate the large scale oceanic circulation based on the World Ocean Circulation Experiment and Java Australia Dynamic Experiment hydrographic data. A linear inverse "box" model is ...