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Heat loss from the Atlantic water layer in the northern Kara Sea: causes and consequences

Heat loss from the Atlantic water layer in the northern Kara Sea: causes and consequences
Heat loss from the Atlantic water layer in the northern Kara Sea: causes and consequences
A distinct, subsurface density front along the eastern St. Anna Trough in the northern Kara Sea is inferred from hydrographic observations in 1996 and 2008–2010. Direct velocity measurements show a persistent northward subsurface current (~ 20 cm s-1) along the St. Anna Trough eastern flank. This sheared flow, carrying the outflow from the Barents and Kara Seas to the Arctic Ocean, is also evident from shipboard observations as well as from geostrophic velocities and numerical model simulations. Although no clear evidence for the occurrence of shear instabilities could be obtained, we speculate that the enhanced vertical mixing along the St. Anna Trough eastern flank promoted by a vertical velocity shear favors the upward heat loss from the intermediate warm Atlantic water layer. The associated upward heat flux is inferred to 50–100 W m-2 using hydrographic data and model simulations. The zone of lowered sea ice thickness and concentration essentially marks the Atlantic water pathway in the St. Anna Trough and adjacent Nansen Basin continental margin from both sea-ice remote sensing observations and model simulations. In fact, the sea-ice shows a consistently delayed freeze-up onset during fall and a reduction in the sea-ice thickness during winter. This is consistent with our results on the enhanced Atlantic water heat loss along the Atlantic water pathway in the St. Anna Trough.
1812-0792
719-730
Dmitrenko, I.A.
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Kirillov, S.A.
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Serra, N.
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Koldunov, N.V.
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Ivanov, V.V.
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Schauer, U.
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Polyakov, I.V.
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Barber, D.
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Janout, M.
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Lien, V.S.
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Makhotin, M.
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Aksenov, Y.
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Dmitrenko, I.A.
f4987f6e-7606-4f9e-a962-7cca1e54f111
Kirillov, S.A.
1ebe3f33-096d-4f3b-953e-a94c779ddea4
Serra, N.
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Koldunov, N.V.
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Ivanov, V.V.
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Schauer, U.
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Polyakov, I.V.
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Barber, D.
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Janout, M.
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Lien, V.S.
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Makhotin, M.
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Aksenov, Y.
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Dmitrenko, I.A., Kirillov, S.A., Serra, N., Koldunov, N.V., Ivanov, V.V., Schauer, U., Polyakov, I.V., Barber, D., Janout, M., Lien, V.S., Makhotin, M. and Aksenov, Y. (2014) Heat loss from the Atlantic water layer in the northern Kara Sea: causes and consequences. Ocean Science, 10 (4), 719-730. (doi:10.5194/os-10-719-2014).

Record type: Article

Abstract

A distinct, subsurface density front along the eastern St. Anna Trough in the northern Kara Sea is inferred from hydrographic observations in 1996 and 2008–2010. Direct velocity measurements show a persistent northward subsurface current (~ 20 cm s-1) along the St. Anna Trough eastern flank. This sheared flow, carrying the outflow from the Barents and Kara Seas to the Arctic Ocean, is also evident from shipboard observations as well as from geostrophic velocities and numerical model simulations. Although no clear evidence for the occurrence of shear instabilities could be obtained, we speculate that the enhanced vertical mixing along the St. Anna Trough eastern flank promoted by a vertical velocity shear favors the upward heat loss from the intermediate warm Atlantic water layer. The associated upward heat flux is inferred to 50–100 W m-2 using hydrographic data and model simulations. The zone of lowered sea ice thickness and concentration essentially marks the Atlantic water pathway in the St. Anna Trough and adjacent Nansen Basin continental margin from both sea-ice remote sensing observations and model simulations. In fact, the sea-ice shows a consistently delayed freeze-up onset during fall and a reduction in the sea-ice thickness during winter. This is consistent with our results on the enhanced Atlantic water heat loss along the Atlantic water pathway in the St. Anna Trough.

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Accepted/In Press date: 20 February 2014
Published date: August 2014
Organisations: Marine Systems Modelling

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Local EPrints ID: 363059
URI: http://eprints.soton.ac.uk/id/eprint/363059
ISSN: 1812-0792
PURE UUID: 88c70332-c9a5-4851-8a3d-afd5ec969ff1

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Date deposited: 12 Mar 2014 13:21
Last modified: 14 Mar 2024 16:18

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Contributors

Author: I.A. Dmitrenko
Author: S.A. Kirillov
Author: N. Serra
Author: N.V. Koldunov
Author: V.V. Ivanov
Author: U. Schauer
Author: I.V. Polyakov
Author: D. Barber
Author: M. Janout
Author: V.S. Lien
Author: M. Makhotin
Author: Y. Aksenov

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