Arctic Ocean response to Greenland Sea wind anomalies in a suite of model simulations

Type Article
Date 2019-08
Language English
Author(s) Muilwijk Morven1, 2, Ilicak Mehmet3, Cornish Sam B.4, Danilov Sergey5, Gelderloos Renske6, Gerdes Rüdiger5, Haid Verena12, Haine Thomas W.N.6, Johnson Helen L.4, Kostov Yavor8, Kovács Tamás5, Lique CamilleORCID7, Marson Juliana M.9, Myers Paul G.9, Scott Jon10, Smedsrud Lars H.1, 2, 11, Talandier Claude12, Wang Qiang5
Affiliation(s) 1 : Geophysical Institute, University of Bergen Bergen ,Norway
2 : Bjerknes Centre for Climate Research Bergen, Norway
3 : Eurasia Institute of Earth Sciences, Istanbul Technical University Istanbul ,Turkey
4 : Department of Earth SciencesUniversity of Oxford Oxford ,UK
5 : Alfred‐Wegener‐Institut Helmholtz‐Zentrum für Polar‐ und Meeresforschung Bremerhaven ,Germany
6 : Department of Earth and Planetary SciencesThe Johns Hopkins University Baltimore ,USA
7 : Laboratoire d'Océanographie Physique et Spatiale, Univ. Brest, CNRS, IRD, Ifremer, IUEM Brest ,France
8 : Department of PhysicsUniversity of Oxford Oxford ,UK
9 : Department of Earth and Atmospheric SciencesUniversity of Alberta Edmonton Alberta, Canada
10 : Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of Technology Cambridge ,USA
11 : University Centre in Svalbard Longyearbyen Svalbard, Norway
12 : Laboratoire d'Océanographie Physique et Spatiale, Univ. Brest, CNRS, IRD, Ifremer, IUEM Brest ,France
Source Journal Of Geophysical Research-oceans (2169-9275) (American Geophysical Union (AGU)), 2019-08 , Vol. 124 , N. 8 , P. 6286-6322
DOI 10.1029/2019JC015101
WOS© Times Cited 10
Note This article also appears in: Forum for Arctic Modeling and Observational Synthesis (FAMOS) 2: Beaufort Gyre Phenomenon
Keyword(s) Arctic Ocean, Atlantic Water, sea ice, wind forcing, model intercomparison, FAMOS
Abstract

Multi‐model Arctic Ocean ``Climate Response Function” (CRF) experiments are analyzed in order to explore the effects of anomalous wind forcing over the Greenland Sea (GS) on poleward ocean heat transport, Atlantic Water (AW) pathways, and the extent of Arctic sea ice. Particular emphasis is placed on the sensitivity of the AW circulation to anomalously strong or weak GS winds in relation to natural variability, the latter manifested as part of the North Atlantic Oscillation (NAO). We find that anomalously strong (weak) GS wind forcing, comparable in strength to a strong positive (negative) NAO index, results in an intensification (weakening) of the poleward AW flow, extending from south of the North Atlantic Subpolar Gyre, through the Nordic Seas, and all the way into the Canadian Basin. Reconstructions made utilizing the calculated CRFs explain ~50 % of the simulated AW flow variance; this is the proportion of variability that can be explained by GS wind forcing. In the Barents and Kara Seas there is a clear relationship between the wind‐driven anomalous AW inflow and the sea ice extent. Most of the anomalous AW heat is lost to the atmosphere, and loss of sea ice in the Barents Sea results in even more heat loss to the atmosphere, and thus effective ocean cooling. Release of passive tracers in a subset of the suite of models reveals differences in circulation patterns and shows that the flow of AW in the Arctic Ocean is highly dependent on the wind stress in the Nordic Seas.

Plain Language Summary

The North Atlantic Current is an extension of the Gulf Stream, which brings warm Atlantic Water northward as the current flows through the Nordic Seas. Eventually it enters the cold deep Arctic Ocean basins through the Barents Sea and Fram Strait. Nine different numerical ocean‐ice models have been analyzed and compared in order to investigate: (1) their ability to simulate this northward flow of Atlantic Water, (2) its dependence on wind forcing, and (3) its impact on Arctic sea ice. Consistently, in all models, stronger winds in the Greenland Sea result in a stronger northward flow of warm Atlantic Water. The response on ocean circulation occurs from the North Atlantic, through the Nordic Seas and the Barents Sea, to the deep Canadian Basin. The flow of warm Atlantic Water within the Arctic Ocean is thus highly dependent on the wind stress in the Nordic Seas. There is particularly clear response in the Barents and Kara Seas where a wind‐driven anomalous warm inflow drives a smaller sea ice extent and thickness, and an increased heat transfer from the ocean to the atmosphere above. Weaker winds in the Greenland Sea produces weaker flow and hence a larger sea ice extent and thickness

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Supporting Information S1 17 18 MB Open access
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Figure S4 91 MB Open access
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Muilwijk Morven, Ilicak Mehmet, Cornish Sam B., Danilov Sergey, Gelderloos Renske, Gerdes Rüdiger, Haid Verena, Haine Thomas W.N., Johnson Helen L., Kostov Yavor, Kovács Tamás, Lique Camille, Marson Juliana M., Myers Paul G., Scott Jon, Smedsrud Lars H., Talandier Claude, Wang Qiang (2019). Arctic Ocean response to Greenland Sea wind anomalies in a suite of model simulations. Journal Of Geophysical Research-oceans, 124(8), 6286-6322. Publisher's official version : https://doi.org/10.1029/2019JC015101 , Open Access version : https://archimer.ifremer.fr/doc/00510/62126/