Mesoscale Eddy Activity and Transport in the Atlantic Water Inflow Region North of Svalbard

Crews, Laura; Sundfjord, Arild; Albretsen, Jon; Hattermann, Tore

doi:10.1002/2017jc013198

Cited by 42 publications

(60 citation statements)

References 46 publications

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“…In this calculation we did not take into account the vertical displacement that would have occurred (from 225‐m depth in transect 1a to 400‐m depth in transect 2a). This velocity is larger (about 5 times) than the eddy translational velocities estimated from a high‐resolution ocean model in the AW inflow north of Svalbard in Crews et al () of about 3.5 cm/s. We could expect the eddy translational velocities to be slightly smaller north of Svalbard compared to the WSC as the current is less energetic (current speed about 40 cm/s in the WSC and about 30 cm/s in the AW inflow north of Svalbard, Perez‐Hernandez et al, ).…”

Section: Discussionmentioning

confidence: 57%

Cooling and Freshening of the West Spitsbergen Current by Shelf‐Origin Cold Core Lenses

et al. 2018

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The West Spitsbergen Current (WSC) cools and freshens as it flows northward along the western Svalbard shelf. The cooling takes place at the ocean surface through interaction with the atmosphere and also in subsurface. We present observations with high horizontal resolution (around 2 km) from a SeaExplorer glider deployed in July 2017 for 14 days in the WSC offshore Kongsfjorden around 79°N. They document small lenses (less than 10‐km diameter) of cold (less than 3.8 °C) and fresh (less than 35.2 g/kg) waters in the core of the WSC, coming from the shelf and contributing to its cooling and freshening. Data show that water from the shelf cascades to the bottom of the slope and then detaches on the offshore side of the WSC core where it is baroclinically unstable. The presence of these lenses from the shelf can be related to the wind regime. Strong southerly winds cause upwelling of the warm Atlantic Water onto the shelf in winter. Weak and/or northerly winds allow modified Atlantic Water formed by mixing with cold waters on the shelf to cascade down the slope, leading to lenses of colder and fresher water protruding into the WSC. If lenses are common in the WSC, they could be contributing significantly to its cooling and freshening especially in summer when the influence of the atmosphere on the cooling of the WSC is less important.

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Section: Discussionmentioning

confidence: 57%

Cooling and Freshening of the West Spitsbergen Current by Shelf‐Origin Cold Core Lenses

et al. 2018

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“…Analyses in this paper are shown from July 2005 to July 2009. Additional information about S800, including discussion of its ability to reproduce boundary current observations in Fram Strait and along the continental slope north of Svalbard, is given in Hattermann et al (), Sundfjord et al (), and Crews et al (). In general, the model was found to reproduce boundary current hydrography well, but with an approximately 1 °C cold bias in the AW that is likely advected into the model from upstream.…”

Section: Methodsmentioning

confidence: 99%

How the Yermak Pass Branch Regulates Atlantic Water Inflow to the Arctic Ocean

2019

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The Yermak Plateau is a topographic obstacle which warm water in the West Spitsbergen Current (Atlantic Water) must pass in order to enter the Arctic Ocean. The main route for Atlantic Water to cross the Yermak Plateau is the Yermak Pass Branch, a winter-intensified pathway characterized by pulse-like high-transport events. Here we use an eddy-resolving sea ice and ocean model to investigate oceanographic conditions that promote flow over the Yermak Plateau. Yermak Pass Branch pulses were associated with a warmer, faster West Spitsbergen Current; these conditions created a region of high offshore Ertel potential vorticity upstream of the plateau. As potential vorticity was low in the current itself, this region of high offshore potential vorticity acted as a barrier that guided flow onto the plateau. During times of enhanced recirculation in Fram Strait, this offshore potential vorticity barrier was weaker, likely allowing the current to deflect away from the continental slope. Through this potential vorticity mechanism, the upstream hydrography of the West Spitsbergen Current can determine how much Atlantic Water crosses the plateau, implying that less dense West Spitsbergen Current core water promotes more inflow into the Arctic Ocean and less recirculation in Fram Strait. Plain Language SummaryWe used an ocean and sea ice model to study a current (the West Spitsbergen Current) which carries relatively warm water to the Arctic Ocean. In a key gateway region called Fram Strait, just before the current enters the Arctic Ocean, some of the water takes a shortcut and returns south along Greenland. The rest flows over a shallower area called the Yermak Plateau. Our goal was to learn what pushed pulses of wintertime flow through one pathway or the other. We found that flow was routed into the Arctic Ocean when the current was warmer and faster. This is because the current must conserve a quantity called potential vorticity, and when the current was warmer and faster, the potential vorticity alongside the current increased. This potential vorticity "wall" guided the flow to enter the Arctic Ocean. This means that if the temperature of the current flowing toward the Arctic Ocean increases, the amount of warm water that actually enters the Arctic Ocean could also increase. CREWS ET AL.

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“…9). In the Fram Strait area, roughly 2000 km upstream of the mooring sites, potential eddy origins were concentrated near the Yermak Plateau, the region north of Spitsbergen with strong mesoscale ocean dynamics (e.g., Hunkins, 1986;D'Asaro and Morison, 1992;Padman et al, 1992;Muench et al, 1992;Vaage et al, 2016;Crews et al, 2017), and further along the continental slope between Spitsbergen and 20 Franz Josef Land. Available mooring observations in this region show strong variability of currents expressed in terms of standard deviations of the velocity components (e.g., Pnyushkov et al, 2015).…”

Section: Two Potential Sources Of Eddy Formation In the Ebmentioning

confidence: 99%

Structure and dynamics of mesoscale eddies over the Laptev Sea continental slope in the Arctic Ocean

Pnyushkov¹,

Polyakov²,

Padman³

et al. 2018

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Mesoscale Eddy Activity and Transport in the Atlantic Water Inflow Region North of Svalbard

Cited by 42 publications

References 46 publications

Cooling and Freshening of the West Spitsbergen Current by Shelf‐Origin Cold Core Lenses

Cooling and Freshening of the West Spitsbergen Current by Shelf‐Origin Cold Core Lenses

How the Yermak Pass Branch Regulates Atlantic Water Inflow to the Arctic Ocean

Structure and dynamics of mesoscale eddies over the Laptev Sea continental slope in the Arctic Ocean

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