Poleward ocean heat transports, sea ice processes, and Arctic sea ice variability in NorESM1-M simulations

Sandø, Anne Britt; Gao, Yongqi; Langehaug, Helene R.

doi:10.1002/2013jc009435

Cited by 49 publications

(46 citation statements)

References 51 publications

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“…An effect of AW heat anomalies has also been suggested for the area north of Svalbard by Onarheim et al (), and here the sea ice is observed to melt effectively if advected over warm AW in the surface layer (Peterson et al, ). The AW heat can thus reduce the sea ice cover through direct bottom melt (Sandø et al, ) and the reduction of sea ice growth during winter. The latter has been suggested to be the most important in the Barents Sea, and this is why the influence of AW is mainly a winter signal (Onarheim et al, ).…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2019

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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.

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Section: Resultsmentioning

confidence: 99%

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

et al. 2019

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“…As follows from ice melting from the bottom. The negative correlations are perhaps more surprising, though an explanation is provided by Sandø et al (2014). They find that more heat transported northward leads to less formation of sea ice in the seasonally ice-covered regions during winter.…”

Section: Discussionmentioning

confidence: 99%

Arctic Ocean Heat Impact on Regional Ice Decay: A Suggested Positive Feedback

Ivanov

Alexeev

Koldunov

et al. 2016

Journal of Physical Oceanography

107

103

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Broad, long-living, ice-free areas in midwinter northeast of Svalbard between 2011 and 2014 are investigated. The formation of these persistent and reemerging anomalies is linked, hypothetically, with the increased seasonality of Arctic sea ice cover, enabling an enhanced influence of oceanic heat on sea ice and, in particular, heat transported by Atlantic Water. The ''memory'' of ice-depleted conditions in summer is transferred to the fall season through excess heat content in the upper mixed layer, which in turn transfers to midwinter via thinner and younger ice. This thinner ice is more fragile and mobile, thus facilitating the formation of polynyas and leads. When openings in ice cover form along the Atlantic Water pathway, weak density stratification at the mixed layer base supports the development of thermohaline convection, which further entrains warm and salty water from deeper layers. Convection-induced upward heat flux from the Atlantic layer retards ice formation, either keeping ice thickness low or blocking ice formation entirely. Certain stages of this chain of events have been examined in a region north of Svalbard and Franz Joseph Land, between 808 and 838N and 158 and 608E, where the top hundred meters of Atlantic inflow through the Fram Strait cools and freshens rapidly. Complementary research methods, including statistical analyses of observations and numerical modeling, are used to support the basic concept that the recently observed retreat of sea ice northeast of Svalbard in winter may be explained by a positive feedback between summer ice decay and the growing influence of oceanic heat on a seasonal time scale.

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“…Increased AW heat transport in recent years with both warmer water and stronger flow, was discussed by Beszczynska-Mo¨ller et al (2012), Piechura and Walczowski (2009) and Polyakov et al (2012a). Model studies of the AW heat transport and bottom melting in the Arctic Ocean suggest that periods of increased heat transport lead to enhanced bottom melting (Alexeev et al, 2013;Sandø et al, 2014). Here, we only consider AW temperature, because there is no available current meter record before the 1990s.…”

Section: Discussionmentioning

confidence: 99%

Loss of sea ice during winter north of Svalbard

Onarheim

Smedsrud

Ingvaldsen

et al. 2014

Tellus A: Dynamic Meteorology and Oceanography

221

240

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A B S T R A C T Sea ice loss in the Arctic Ocean has up to now been strongest during summer. In contrast, the sea ice concentration north of Svalbard has experienced a larger decline during winter since 1979. The trend in winter ice area loss is close to 10% per decade, and concurrent with a 0.38C per decade warming of the Atlantic Water entering the Arctic Ocean in this region. Simultaneously, there has been a 28C per decade warming of winter mean surface air temperature north of Svalbard, which is 20Á45% higher than observations on the west coast. Generally, the ice edge north of Svalbard has retreated towards the northeast, along the Atlantic Water pathway. By making reasonable assumptions about the Atlantic Water volume and associated heat transport, we show that the extra oceanic heat brought into the region is likely to have caused the sea ice loss. The reduced sea ice cover leads to more oceanic heat transferred to the atmosphere, suggesting that part of the atmospheric warming is driven by larger open water area. In contrast to significant trends in sea ice concentration, Atlantic Water temperature and air temperature, there is no significant temporal trend in the local winds. Thus, winds have not caused the long-term warming or sea ice loss. However, the dominant winds transport sea ice from the Arctic Ocean into the region north of Svalbard, and the local wind has influence on the year-to-year variability of the ice concentration, which correlates with surface air temperatures, ocean temperatures, as well as the local wind.

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Poleward ocean heat transports, sea ice processes, and Arctic sea ice variability in NorESM1-M simulations

Cited by 49 publications

References 51 publications

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

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

Arctic Ocean Heat Impact on Regional Ice Decay: A Suggested Positive Feedback

Loss of sea ice during winter north of Svalbard

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