North Atlantic warming: patterns of long-term trend and multidecadal variability

Polyakov, Igor V.; Alexeev, V. A.; Bhatt, Uma S.; Polyakova, E. I.; Zhang, Xiangdong

doi:10.1007/s00382-008-0522-3

Cited by 88 publications

(50 citation statements)

References 66 publications

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“…The available SST gridded data sets HadISST (Rayner et al, 2006) and ERSSTv3 (Smith and Reynolds, 2004) as well as the Simple Ocean Data Assimilation (SODA) reanalysis (Carton and Giese, 2008) are all characterized by a cooling trend in the subpolar gyre region (Drijfhout et al, 2012;Kim and An, 2012). Polyakov et al (2010) have used historical data from the North Atlantic Ocean and decomposed the changes between the 1920s and present into non-linear trend and multidecadal variability patterns. The large-scale non-linear trend pattern resembles the 20th-century SST trend in the HadISST and is characterized by cooling over the subpolar gyre (see their Fig.…”

Section: Discussionmentioning

confidence: 99%

Enhanced 20th-century heat transfer to the Arctic simulated in the context of climate variations over the last millennium

2014

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Abstract. Oceanic heat transport variations, carried by the northward-flowing Atlantic Water, strongly influence Arctic sea-ice distribution, ocean-atmosphere exchanges, and pan-Arctic temperatures. Palaeoceanographic reconstructions from marine sediments near Fram Strait have documented a dramatic increase in Atlantic Water temperatures over the 20th century, unprecedented in the last millennium. Here we present results from Earth system model simulations that reproduce and explain the reconstructed exceptional Atlantic Water warming in Fram Strait in the 20th century in the context of natural variability during the last millennium. The associated increase in ocean heat transfer to the Arctic can be traced back to changes in the ocean circulation in the subpolar North Atlantic. An interplay between a weakening overturning circulation and a strengthening subpolar gyre as a consequence of 20th-century global warming is identified as the driving mechanism for the pronounced warming along the Atlantic Water path toward the Arctic. Simulations covering the late Holocene provide a reference frame that allows us to conclude that the changes during the last century are unprecedented in the last 1150 years and that they cannot be explained by internal variability or natural forcing alone.

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Section: Discussionmentioning

confidence: 99%

Enhanced 20th-century heat transfer to the Arctic simulated in the context of climate variations over the last millennium

2014

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“…On centennial time scales, Polyakov et al (2003) found that the limited data records of fast-ice thickness and extent in the Kara, Laptev, East Siberian, and Chukchi marginal seas lack a statistically significant long-term trend and are dominated by multidecadal/decadal oscillations over the 1900-2000 period.…”

Section: Introductionmentioning

confidence: 98%

“…The Atlantic meridional overturning circulation (AMOC) is often thought to be a major source of decadal/multidecadal variability in the climate system (e.g., Delworth and Mann 2000;Polyakov et al 2010). In coupled model simulations (e.g., Knight et al 2005;) the AMOC contributes a substantial fraction of the low-frequency variability of the basin-averaged North Atlantic sea surface temperatures, that is, the Atlantic multidecadal oscillation (AMO).…”

Section: Introductionmentioning

confidence: 99%

Impact of the Atlantic Meridional Overturning Circulation (AMOC) on Arctic Surface Air Temperature and Sea Ice Variability

2011

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The simulated impact of the Atlantic meridional overturning circulation (AMOC) on the low-frequency variability of the Arctic surface air temperature (SAT) and sea ice extent is studied with a 1000-year-long segment of a control simulation of the Geophysical Fluid Dynamics Laboratory Climate Model version 2.1. The simulated AMOC variations in the control simulation are found to be significantly anticorrelated with the Arctic sea ice extent anomalies and significantly correlated with the Arctic SAT anomalies on decadal time scales in the Atlantic sector of the Arctic. The maximum anticorrelation with the Arctic sea ice extent and the maximum correlation with the Arctic SAT occur when the AMOC index leads by one year. An intensification of the AMOC is associated with a sea ice decline in the Labrador, Greenland, and Barents Seas in the control simulation, with the largest change occurring in winter. The recent declining trend in the satellite-observed sea ice extent also shows a similar pattern in the Atlantic sector of the Arctic in the winter, suggesting the possibility of a role of the AMOC in the recent Arctic sea ice decline in addition to anthropogenic greenhouse-gas-induced warming. However, in the summer, the simulated sea ice response to the AMOC in the Pacific sector of the Arctic is much weaker than the observed declining trend, indicating a stronger role for other climate forcings or variability in the recently observed summer sea ice decline in the Chukchi, Beaufort, East Siberian, and Laptev Seas.

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“…On larger scales, there is strong multi-decadal variability in SST in the NA (e.g., Deser et al, 2010;Polyakov, Alexeev, Bhatt, Polyakova, & Zhang, 2010;Terray, 2012). In particular, the Atlantic Multi-decadal Oscillation (AMO), also referred to as the Atlantic Multi-decadal Variability (AMV; Hakkinen, Rhines, & Worthen, 2011;Ou, 2012), has been identified in spatially averaged SST (over the NA) with a predominant variation with a period of approximately 60-70 years (Knight, Allan, Folland, Vellinga, & Mann, 2005;Wang, Dong, Evan, Foltz, & Lee, 2012).…”

Section: Introductionmentioning

confidence: 99%

Trends and Variability of Sea Surface Temperature in the Northwest Atlantic from Three Historical Gridded Datasets

Loder

Wang

2015

Atmosphere-Ocean

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Historical variability in sea surface temperature (SST) in the North Atlantic (NA) is examined using trend and Empirical Orthogonal Function (EOF) analyses of annual and summer means from three interpolated monthly datasets: Hadley Centre Sea Ice and Sea Surface Temperature (HadISST1), Extended Reconstruction of SST (ERSST), and Centennial in situ Observation-Based Estimates (COBE). Comparisons with time series of upper-ocean temperature from four monitoring sites off Atlantic Canada reveal substantial similarity in the interannual to multi-decadal variability but notable differences in the longer-term trends. The magnitude of decadal-scale variability is comparable to, or greater than, the long-term changes in all of the datasets; together with the trend discrepancies, this needs to be considered in climate change applications. Averaged over the NA, the annual means have a long-term increasing trend and a pronounced multi-decadal variation, resembling those in global mean (land-ocean) surface temperature and the Atlantic Multi-decadal Oscillation (AMO). There is remarkable similarity in the spatial and temporal variability of the three leading EOF modes from the different gridded datasets, with the first highly correlated with the AMO, the second modestly correlated with the winter North Atlantic Oscillation, and the third apparently related to ocean circulation variability. Trends since 1981 are generally two to three times larger than those since 1900 and 1950, which is at least partly related to the phase of the AMO. Trends in the summer means are generally larger than in the annual means. Overall, the results provide support for both anthropogenic global warming and decadal-scale natural variations making important contributions to ocean climate variability in the Northwest Atlantic.RÉSUMÉ [Traduit par la rédaction] Nous examinons la variabilité passée des températures à la surface de la mer (SST) de l'Atlantique Nord, et ce, en analysant les tendances et les fonctions orthogonales empiriques (FOE) des moyennes annuelles et estivales de trois séries de données mensuelles interpolées : les températures à la surface de la glace marine et de la mer issues du Hadley Centre (HadISST1), la reconstitution élargie des SST (ERSST) et les estimations provenant d'observations in situ centennales (COBE). Les comparaisons avec des séries temporelles de la température de la couche supérieure de l'océan, provenant de quatre sites de mesure au large de la côte atlantique canadienne, révèlent des similitudes substantielles dans les variabilités interannuelles à multidécennales, mais des différences notables dans les tendances à plus long terme. La magnitude de la variabilité à l'échelle décennale est comparable ou supérieure aux changements à long terme dans toutes les séries de données. Ce résultat et les différences dans les tendances devront être pris en considération dans le cadre d'études sur les changements climatiques. En moyenne, sur l'Atlantique Nord, les moyennes annuelles montrent une tendance à long terme à la ha...

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North Atlantic warming: patterns of long-term trend and multidecadal variability

Cited by 88 publications

References 66 publications

Enhanced 20th-century heat transfer to the Arctic simulated in the context of climate variations over the last millennium

Enhanced 20th-century heat transfer to the Arctic simulated in the context of climate variations over the last millennium

Impact of the Atlantic Meridional Overturning Circulation (AMOC) on Arctic Surface Air Temperature and Sea Ice Variability

Trends and Variability of Sea Surface Temperature in the Northwest Atlantic from Three Historical Gridded Datasets

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