Across the Arctic front west of Spitsbergen: high-resolution CTD sections from 1998-2000

Abstract

The structure of the oceanic Arctic front west of Spitsbergen is investigated using data from high‐resolution CTD sections from September 1998‐2000. Below the fresher surface layer, the front appears as a temperature‐salinity front situated near the shelf break. No clear corresponding front in density is found. Our analysis suggests that barotropic front instability is a main factor in provoking subsurface cross‐front exchange. The subsurface heat loss in the West Spitsbergen Current due to this exchange is estimated to be of the same order of magnitude as the heat loss to the atmosphere in the surface layer.

Atlantic Water advection vs. glacier dynamics in northern Spitsbergen since early deglaciation

“…This current follows the western shelf break of the Barents Sea (the core of the WSC mainly appears between the 300 and 1000 m isobaths; e.g. Saloranta and Svendsen, 2001), continuing northward into the eastern Fram Strait (Rudels, 2009) Locarnini et al, 2013;Schlitzer, 2015). White rectangle: Svalbard area as shown in (b).…”

“…Thus, AW is only able to enter Svalbard's shelf and fjords when surmounting this front. Barotropic instabilities seem to be the major mechanisms allowing AW to cross this temperaturesalinity front (Cottier et al, 2005;Saloranta and Svendsen, 2001;Teigen et al, 2010). Especially during winter, windinduced upwelling also significantly promotes AW advection across the Arctic (Coastal) Front (Cottier et al, 2005(Cottier et al, , 2007.…”

Plankton patchiness in the Polar Front region of the West Spitsbergen Shelf

“…The convergence, mixing and exchange of the Atlantic-and Arctic-origin water masses on the WSS (Saloranta & Svendsen 2001) results in a complex hydrography. On its offshore side, the West Spitsbergen Current (WSC) carries warm and saline Atlantic water into the Arctic Ocean (Saloranta & Haugan 2001, Walczowski et al 2005.…”

“…Therefore, the Arctic-type water occupying the WSS is warmer and fresher than typical Arctic water (colder than 0°C and saltier than 34.8). The Arctic-type water carried over the shelf and the Atlantic water transported above the upper slope are typically separated by a frontal zone, which is a part of the larger-scale Polar Front system (Loeng 1991, Saloranta & Svendsen 2001, Walczowski 2013. The Polar Front west of Spits bergen is characterized by a density gradient only in the fresher surface water layer of approximately 50 m, while beneath this layer, the front is density compensated and manifested through strong temperature and salinity gradients (Saloranta & Svendsen 2001, Walczowski 2013.…”

Fluxes and fate of dissolved methane released at the seafloor at the landward limit of the gas hydrate stability zone offshore western Svalbard

“…Because the water depth is shallow, larger methane bubbles can rise all the way through the water column and methane concentrations are high even in surface waters, establishing a large concentration gradient between shelf and upper slope waters (Figure 7). Cold Arctic ESC water on the shelf is separated from warm Atlantic WSC water on the upper slope by a strong density-compensated halocline (the Arctic Front) [e.g., Cottier and Venables, 2007;Saloranta and Svendsen, 2001], which allows offshore isopycnal mixing of methane from the shelf with the upper water column at the GHSZ limit. Mechanisms for enhanced isopycnal turbulent diffusion across the Arctic Front include barotropic instability due to the difference in current speed between WSC and ESC waters [Saloranta and Svendsen, 2001;Teigen et al, 2010] and interleaving and cabbeling: isopycnal mixing of water with different salinity and temperature to produce parcels of denser water which then sink, generating vertical mixing [Cottier and Venables, 2007].…”