Mechanisms of interannual variability of deep convection in the Greenland sea

Bashmachnikov, Igor; Федоров, А. В.; Golubkin, Pavel; Vesman, Anna; Selyuzhenok, Valeria; Gnatiuk, Natalia; Bobylev, Leonid; Hodges, Kevin I.; Dukhovskoy, Dmitry S.

doi:10.1016/j.dsr.2021.103557

Cited by 15 publications

(29 citation statements)

References 162 publications

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“…. Latonin et al, 2022 ing to the results of [Bashmachnikov et al, 2021], the variability of the salinity of the upper part of the Greenland Sea is primarily associated not with the freshwater flux from the Arctic Ocean, but with the variability of the inflow of the Atlantic water. On the other hand, studies of winter convection in the northern part of the Norwegian Sea indicate that the intensification of convection is associated with an increase in the cyclonic vorticity over this region [Fedorov et al, 2021].…”

Section: Discussionmentioning

confidence: 97%

“…Whether the change in the atmospheric advection of heat and moisture into the Central Arctic is related to the winter convection dynamics in the Nordic Seas should be verified separately. For instance, for the period from 1993 to 2016 considered in the work of [Bashmachnikov et al, 2021], a convection in the Greenland Sea has intensified since the 2000s. As according to the AOO index, the anticyclonic circulation regime has prevailed in the Central Arctic since 1996, associated with a decrease in the atmospheric heat transport into the Central Arctic, for the mechanism's operation proposed in [Proshutinsky et al, 2015], the convection in the Nordic Seas should have weakened instead.…”

Section: Discussionmentioning

confidence: 99%

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Bjerknes compensation mechanism as a possible trigger of the low-frequency variability of Arctic amplification

Latonin

Bashmachnikov

Bobylev

2022

Russian Journal of Earth Sciences

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The causes of Arctic amplification are widely debated, and a cohesive picture has not been obtained yet. This study has investigated the role of the Atlantic meridional oceanic and atmospheric heat transport into the Arctic in the emergence of Arctic amplification. The integral advective fluxes in the layer of Atlantic waters and in the lower troposphere were considered. The results show a strong coupling between the meridional heat fluxes and regional Arctic amplification in the Eurasian Arctic on the decadal time scales (10–15 years). We argue that the low-frequency variability of Arctic amplification is regulated via the chain of oceanic heat transport — atmospheric heat transport — Arctic amplification. The atmospheric response to the ocean influence occurs with a delay of three years and is attributed to the Bjerknes compensation mechanism. In turn, the atmospheric heat and moisture transport directly affects the magnitude of Arctic amplification, with the latter lagging by one year. Thus, the variability of oceanic heat transport at the southern boundary of the Nordic Seas might be a predictor of the Arctic amplification magnitude over the Eurasian Basin of the Arctic Ocean with a lead time of four years. The results are consistent with the concept of the decadal Arctic climate variability expressed via the Arctic Ocean Oscillation index.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Bjerknes compensation mechanism as a possible trigger of the low-frequency variability of Arctic amplification

Latonin

Bashmachnikov

Bobylev

2022

Russian Journal of Earth Sciences

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“…All convective areas are observed with cyclonic gyres by rising isopycnals over the weakly stratified intermediate waters in their central areas (the cold water dome), thus decreasing the thickness of the upper low-buoyancy layer. The interannual intensity of the deepwater formation in the convection sites of the North Atlantic is primarily regulated by oceanic heat and salt advection and by intensive heat release from the sea surface to the atmosphere, among other factors (Bashmachnikov et al, 2021;Sarafanov et al, 2012). For the Greenland Sea, authors stress the importance of variability of the ice cover and the Atlantic water inflow for the development of convection, while for the Norwegian Sea the ocean-atmosphere heat exchange governs the intensity of convection (Bashmachnikov et al, 2021;Böning et al, 2016;Fedorov et al, 2021;Fedorov and Bashmachnikov, 2020;Glessmer et al, 2014;Moore et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…The interannual intensity of the deepwater formation in the convection sites of the North Atlantic is primarily regulated by oceanic heat and salt advection and by intensive heat release from the sea surface to the atmosphere, among other factors (Bashmachnikov et al, 2021;Sarafanov et al, 2012). For the Greenland Sea, authors stress the importance of variability of the ice cover and the Atlantic water inflow for the development of convection, while for the Norwegian Sea the ocean-atmosphere heat exchange governs the intensity of convection (Bashmachnikov et al, 2021;Böning et al, 2016;Fedorov et al, 2021;Fedorov and Bashmachnikov, 2020;Glessmer et al, 2014;Moore et al, 2015). In the SPG the mechanisms shaping the interannual variability of deep convection are still under discussion.…”

Section: Introductionmentioning

confidence: 99%

Deep convection in the Subpolar Gyre: Do we have enough data to estimate its intensity?

Федоров

Bashmachnikov

Iakovleva

et al. 2023

Dynamics of Atmospheres and Oceans

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“…As one of the sources of the densest portion of AMOC, the convection depth in the GSG often exceeds 1500 m during winter (Wadhams et al, 2004;Latarius and Quadfasel, 2016). The deep convection intensity in the GSG is primarily associated with upper-ocean salinity related to the variability in the advection of re-circulating branches of the EGC and WSC, and local sea ice melt (Bashmachnikov et al, 2021). The thermohaline characteristics of re-circulation in the central GS interact with a mechanism that may govern the thermohaline system between the AMOC and the deep convection on interdecadal time scales (Stommel, 1958;Levermann and Born, 2007).…”

Section: Introductionmentioning

confidence: 99%

Variability of Near-Surface Salinity in the Nordic Seas Over the Past Three Decades (1991-2019)

Park

Kim²,

Cho³

2022

Front. Mar. Sci.

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The Nordic Seas have been widely implicated by deep water formation as a part of Atlantic Meridional Overturning Circulation. This study explores the spatiotemporal variations in the near-surface salinity over the Nordic Seas associated with surface freshening factors by using monthly TOPAZ4 reanalysis data from 1991 to 2019. We first show that reliability of TOPAZ4 data compared to the salinity products of other reanalysis data, satellite data, and in-situ measurements in the Nordic Seas. The salinity variability was larger in the Greenland Sea (GS) than in the Norwegian Sea (NS) on both time scales of seasonal and interannual. The seasonal change of GS salinity was coincident with the seasonality of sea ice extent. The longer-time variations are decomposed by empirical orthogonal function (EOF) analysis. The GS salinity is mainly affected by current advection (29%) and sea ice extent (11%). The interannual response of salinity to the sea ice extent over the GS differs by season. NS salinity variability responds to the strength of the Subpolar Gyre associated with a large-scale atmospheric system that caused the freshening event in the mid-1990s. The propagation of the northward Atlantic Water core is observed over the period of about 3 years from the Faroe Shetland Channel to the Fram Strait at a speed of 2.6-6.5° year-1. Other freshening factors such as sea ice export from the Arctic, freshwater flux at the Fram Strait, and net precipitation are also discussed. For the past three decades, the continuous trend appeared only in the sea ice extent, which might be a signal of climate changes over high latitude. However, there was no significant trend other than the periodic change in a few years to the decadal time scale in the salinity of GS and NS. As preconditioning for deep convection, near-surface salinity within Greenland Sea Gyre was influenced by salinity fluctuation in both GS and NS.

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Mechanisms of interannual variability of deep convection in the Greenland sea

Cited by 15 publications

References 162 publications

Bjerknes compensation mechanism as a possible trigger of the low-frequency variability of Arctic amplification

Bjerknes compensation mechanism as a possible trigger of the low-frequency variability of Arctic amplification

Deep convection in the Subpolar Gyre: Do we have enough data to estimate its intensity?

Variability of Near-Surface Salinity in the Nordic Seas Over the Past Three Decades (1991-2019)

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