Winter to summer oceanographic observations in the Arctic Ocean north of Svalbard

Abstract

Oceanographic observations from the Eurasian Basin north of Svalbard collected between January and June 2015 from the N‐ICE2015 drifting expedition are presented. The unique winter observations are a key contribution to existing climatologies of the Arctic Ocean, and show a ∼100 m deep winter mixed layer likely due to high sea ice growth rates in local leads. Current observations for the upper ∼200 m show mostly a barotropic flow, enhanced over the shallow Yermak Plateau. The two branches of inflowing Atlantic Water are partly captured, confirming that the outer Yermak Branch follows the perimeter of the plateau, and the inner Svalbard Branch the coast. Atlantic Water observed to be warmer and shallower than in the climatology, is found directly below the mixed layer down to 800 m depth, and is warmest along the slope, while its properties inside the basin are quite homogeneous. From late May onwards, the drift was continually close to the ice edge and a thinner surface mixed layer and shallower Atlantic Water coincided with significant sea ice melt being observed.

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

“…A subsurface salinity maximum between 100 m and 400 m depth was found in all three sections, similar to previous studies in this region (Cokelet et al, 2008;Våge et al, 2016;Meyer et al, 2016). Compared to the climatology, the salinities were higher in all sections.…”

“…Similarly, observations made from drifting pack ice north of Svalbard in spring 2015 showed warmer and shallower AW compared to the climatology (Meyer et al, 2016).…”

“…• E (Perkin and Lewis, 1984;Cokelet et al, 2008;Våge et al, 2016;Meyer et al, 2016). Acoustically-tracked subsurface floats revealed a shortcut across the YP (Gascard et al, 1995), through a topographic passage at 80 (Padman and Dillon, 1991;Perkin and Lewis, 1984).…”

“…Fer et al (2010) conclude 10 that internal-wave activity and mixing show variability related to topography and hydrography; thus, the path of the WSC will affect the cooling and freshening rates the AW experiences. Over the steep slopes and prominent topography of the YP, and over the core of the AW branches, vertical mixing can play an important role in modifying the AW properties (Padman and Dillon, 1991;Meyer et al, 2016;Sirevaag and Fer, 2009). In the surface mixed layer in proximity to the WSC, turbulent heat fluxes of 200-300 W m were measured (Sirevaag and Fer, 2009).…”

Observations of brine plumes below Arctic sea ice

“…The observations are collected in June 2015, in the MIZ north of Svalbard (Figure 1). The data is a subset of a previously reported under-ice turbulence data set (Peterson et al, 2017(Peterson et al, , 2016, and is part of the Norwegian Young Sea Ice Cruise (N-ICE2015, Granskog et al, 2016). …”