The impact of Siberian coastal polynyas on shelf-derived Arctic Ocean halocline waters.

Bauch, Dorothea , Hölemann, Jens A. , Dmitrenko, Igor A., Janout, Markus A., Nikulina, Anna, Kirillov, Sergey A., Krumpen, Thomas, Kassens, Heidemarie and Timokhov, Leo (2012) The impact of Siberian coastal polynyas on shelf-derived Arctic Ocean halocline waters. Open Access Journal of Geophysical Research: Oceans, 117 (C4). C00G12. DOI 10.1029/2011JC007282.

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Supplementary data:

Abstract

Hydrographic and stable oxygen isotope (H218O/H216O) sampling was carried out within the West New Siberian (WNS) coastal polynyas in the southern Laptev Sea in late winters 2008 and 2009. The impact of sea-ice formation on the water column was quantified by a salinity/{lower case delta}18O mass balance. Several stations had vertically homogeneous physical properties in April/May 2008 and featured polynya-formed local bottom water with elevated signals of brine released during sea-ice formation and elevated fractions of river water. The polynya-formed bottom water was fresher than surrounding bottom waters. At other stations salinity/{lower case delta}18O correlation showed well defined mixing lines for bottom and surface layers. In March/April 2009 surface waters were strongly influenced by Lena River water and local polynya activity with elevated brine signals reached to intermediate depth, but did not penetrate the bottom layer in the highly stratified water column. Inventory values of sea-ice formation were comparable in both years, but freshwater distributions from the preceding summers were different. Therefore, the observed difference in the impact of polynya activity on the water column is not primarily controlled by the amount of sea-ice formed during winter but by preconditioning from the preceding summer. Only in years when the river plume is mostly absent in the polynya region stratification is weak and allows winter sea-ice formation to reach the bottom layer. Thus summer stratification controls the influence of local polynya water on the shelf's bottom hydrography and, as bottom water is exported, impacts on the source water of shelf-derived halocline waters.

Document Type: Article
Additional Information: WOS:000302496400001
Keywords: Polar Research; Siberian shelves ; Oxygen isotopes ; Polynya ; Sea-ice formation; Laptev Sea; River-runoff; Fresh-water; Hydrography; Ice; Transport; Balance; Model
Research affiliation: AWI
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1029/2011JC007282
ISSN: 2169-9275
Projects: Polynya, Laptev Sea System
Expeditions/Models/Experiments:
Date Deposited: 20 Mar 2012 09:00
Last Modified: 27 Feb 2018 09:26
URI: http://oceanrep.geomar.de/id/eprint/14070

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