Structure and variability of the boundary current in the Eurasian Basin of the Arctic Ocean

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

“…Maximum eddy rotation speeds are comparable with the long-term mean current speed of 4-5 cm/s at the Laptev Sea 25 continental slope (Pnyushkov et al, 2015). Higher values of the rotational speed were reported for eddies found in the Canadian Basin (Krishfield et al, 2002;Pickart et al, 2005;Timmermans et al, 2008;Kawaguchi et al, 2012).…”

“…Various mechanisms may affect the frequency of eddy registration at the moorings. The weakened eddy activity between April and December 2009 at the M1f mooring was concurrent with large-scale changes in the thermohaline state of the EB, including reversal of direction of the ACBC (see Pnyushkov et al, 2015 for details). We argue that the changes in the thermohaline state of the eastern Eurasian Basin unlikely modify the intensity of eddy generation (e.g., baroclinic instability of the ACBC), but alternate the pathway of eddy advection along the EB slope from Fram Strait or Severnaya 5…”

“…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). This strong variability likely indicates current instability similar to baroclinic instability of the West Spitsbergen Current in Fram Strait (Teigen et al, 2011).…”

“…Previous analyses of this dataset include studies of long-term changes of the 5 thermohaline state of the EB and evaluation of interannual changes of the ACBC in the EB (Polyakov et al, 2008Pnyushkov et al, 2015). Those papers provide a detailed description of this dataset, which includes multiple ship-based CTD surveys complemented by ITP (www.whoi.edu/itp) observations, providing extensive year-round measurements of temperature and salinity in the upper ~800-m ocean layer.…”

Hydrography, transport and mixing of the West Spitsbergen Current: the Svalbard Branch in summer 2015

“…A large fraction of the northward flow is the West Spitsbergen Current (WSC), located on the eastern side of Fram Strait, which is a northward flowing extension of the Norwegian Atlantic Current. The mean net volume transport in the WSC, measured along an array at 78 , and changes structure from a mainly barotropic flow to a baroclinic flow (Pnyushkov et al, 2015). AW transported by the WSC is the major heat and salinity source for the Arctic Ocean (Boyd and D'Asaro, 1994;Aagaard et al, 1985;Rudels et al, 2015), and Arctic conditions are highly influenced by changes in the AW inflow properties (Polyakov et al, 2017).…”