Arctic Ocean Response to Greenland Sea Wind Anomalies in a Suite of Model Simulations

Morven Muilwijk1, Mehmet Ilicak2, Sam Cornish3, Sergey Danilov4, Renske Gelderloos5, Rüdiger Gerdes4, Verena Haid6, Thomas W N Haine7,8, Helen Johnson9, Yavor Kostov10, Tamás Kovács Sr4, Camille Lique11, Juliana Marson12, Paul Glen Myers13, Jeffery R Scott14, Lars Henrik Smedsrud1, Claude Talandier15 and Qiang Wang4, (1)Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research, Bergen, Norway, (2)Istanbul Technical University, Eurasia Institute of Earth Sciences, Istanbul, Turkey, (3)University of Oxford, Earth Sciences, Oxford, United Kingdom, (4)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (5)Johns Hopkins University, Baltimore, MD, United States, (6)Now at Laboratoire d'Océanographie Physique et Spatiale, Centre National de la Recherche Scientifique, Plouzané, France, (7)Johns Hopkins Univ, Baltimore, MD, United States, (8)Johns Hopkins University, Department of Earth & Planetary Sciences, Baltimore, MD, United States, (9)University of Oxford, Oxford, United Kingdom, (10)University of Exeter, Exeter, United Kingdom, (11)Laboratoire de Physique des Océans, Ifremer, Brest, France, (12)University of Manitoba, Centre for Earth Observation Science, Winnipeg, MB, Canada, (13)University of Alberta, Edmonton, AB, Canada, (14)MIT, Cambridge, MA, United States, (15)CNRS, Laboratoire d'océanographie physique et spatiale, Plouzane, France
Abstract:
Multimodel Arctic Ocean “climate response function” 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. We find that anomalously strong (weak) GS wind forcing, comparable in strength to a strong positive (negative) North Atlantic Oscillation 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 climate response functions 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.