Response of the North Atlantic dynamic sea level and circulation to Greenland meltwater and climate change in an eddy-permitting ocean model

Saenko, Oleg A.; Yang, Duo; Myers, Paul G.

doi:10.1007/s00382-016-3495-7

Cited by 19 publications

(20 citation statements)

References 30 publications

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“…Thus, we conclude that presently the GFWA could not cause the observed freshening in the SPNA during the 2010s. This result agrees with the previous study of Saenko et al (), who also show that the GFWA of similar magnitude (and even double of this magnitude) has negligibly small impact on the SPNA thermohaline fields, barely impacting AMOC. Thus, the present model experiments suggest that additional freshwater sources must have contributed to the recent freshening.…”

Section: Gfwa and Observed Fresheningsupporting

confidence: 93%

Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic

et al. 2019

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The cumulative Greenland freshwater flux anomaly has exceeded 5,000 km 3 since the 1990s. The volume of this surplus freshwater is expected to cause substantial freshening in the North Atlantic. Analysis of hydrographic observations in the subpolar seas reveals freshening signals in the 2010s. The sources of this freshening are yet to be determined. In this study, the relationship between the surplus Greenland freshwater flux and this freshening is tested by analyzing the propagation of the Greenland freshwater anomaly and its impact on salinity in the subpolar North Atlantic based on observational data and numerical experiments with and without the Greenland runoff. A passive tracer is continuously released during the simulations at freshwater sources along the coast of Greenland to track the Greenland freshwater anomaly. Tracer budget analysis shows that 44% of the volume of the Greenland freshwater anomaly is retained in the subpolar North Atlantic by the end of the simulation. This volume is sufficient to cause strong freshening in the subpolar seas if it stays in the upper 50–100 m. However, in the model the anomaly is mixed down to several hundred meters of the water column resulting in smaller magnitudes of freshening compared to the observations. Therefore, the simulations suggest that the accelerated Greenland melting would not be sufficient to cause the observed freshening in the subpolar seas and other sources of freshwater have contributed to the freshening. Impacts on salinity in the subpolar seas of the freshwater transport through Fram Strait and precipitation are discussed.

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Section: Gfwa and Observed Fresheningsupporting

confidence: 93%

Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic

et al. 2019

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“…This type of SSH anomaly in the Canadian Archipelago is also a feature of a weaker than normal AMOC at 40°N (Figure j). The change in the ocean circulation associated with a weakening of the AMOC leads quasi‐instantaneously to regional dynamic sea level rise (Levermann et al, ; Saenko et al, ). This has been observed in the North Atlantic; for example, a 128‐mm jump in coastal sea level north of New York City in 2009–2010 has been associated with a 30% reduction of the AMOC (Goddard et al, ).…”

Section: Discussion: Mechanisms Behind Strait Correlationsmentioning

confidence: 99%

Interconnectivity Between Volume Transports Through Arctic Straits

et al. 2018

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Arctic heat and freshwater budgets are highly sensitive to volume transports through the Arctic‐Subarctic straits. Here we study the interconnectivity of volume transports through Arctic straits in three models; two coupled global climate models, one with a third‐degree horizontal ocean resolution (High Resolution Global Environmental Model version 1.1 [HiGEM1.1]) and one with a twelfth‐degree horizontal ocean resolution (Hadley Centre Global Environment Model 3 [HadGEM3]), and one ocean‐only model with an idealized polar basin (tenth‐degree horizontal resolution). The two global climate models indicate that there is a strong anticorrelation between the Bering Strait throughflow and the transport through the Nordic Seas, a second strong anticorrelation between the transport through the Canadian Arctic Archipelago and the Nordic Seas transport, and a third strong anticorrelation is found between the Fram Strait and the Barents Sea throughflows. We find that part of the strait correlations is due to the strait transports being coincidentally driven by large‐scale atmospheric forcing patterns. However, there is also a role for fast wave adjustments of some straits flows to perturbations in other straits since atmospheric forcing of individual strait flows alone cannot lead to near mass balance fortuitously every year. Idealized experiments with an ocean model (Nucleus for European Modelling of the Ocean version 3.6) that investigate such causal strait relations suggest that perturbations in the Bering Strait are compensated preferentially in the Fram Strait due to the narrowness of the western Arctic shelf and the deeper depth of the Fram Strait.

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“…An issue of potentially similar importance is the area where deep convection occurs, which is much larger in models than is believed to be the case in observations (e.g., Feucher et al, ). This issue can at least in part be related to resolution and eddy exchange off the west Greenland Current (e.g., Saenko et al, 2017; Chanut et al, 2008). However, that in itself does not seem to be sufficient as the AMOC cell in VIKING005 is still too shallow (and not deeper than other models with poor overflows, Figure ).…”

Section: Areas In Need Of Improvementmentioning

confidence: 99%

The Atlantic Meridional Overturning Circulation in High‐Resolution Models

et al. 2020

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The Atlantic meridional overturning circulation (AMOC) represents the zonally integrated stream function of meridional volume transport in the Atlantic Basin. The AMOC plays an important role in transporting heat meridionally in the climate system. Observations suggest a heat transport by the AMOC of 1.3 PW at 26°N-a latitude which is close to where the Atlantic northward heat transport is thought to reach its maximum. This shapes the climate of the North Atlantic region as we know it today. In recent years there has been significant progress both in our ability to observe the AMOC in nature and to simulate it in numerical models. Most previous modeling investigations of the AMOC and its impact on climate have relied on models with horizontal resolution that does not resolve ocean mesoscale eddies and the dynamics of the Gulf Stream/North Atlantic Current system. As a result of recent increases in computing power, models are now being run that are able to represent mesoscale ocean dynamics and the circulation features that rely on them. The aim of this review is to describe new insights into the AMOC provided by high-resolution models. Furthermore, we will describe how high-resolution model simulations can help resolve outstanding challenges in our understanding of the AMOC. Key Points:• Observations and high-resolution models have changed view on the AMOC pathways • High-resolution models suggest the presence of previously unknown high-frequency AMOC variability • High-resolution models allow to estimate the intrinsic/chaotic component of the AMOCCorrespondence to:

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Response of the North Atlantic dynamic sea level and circulation to Greenland meltwater and climate change in an eddy-permitting ocean model

Cited by 19 publications

References 30 publications

Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic

Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic

Interconnectivity Between Volume Transports Through Arctic Straits

The Atlantic Meridional Overturning Circulation in High‐Resolution Models

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