Recirculation in the Fram Strait and transports of water in and north of the Fram Strait derived from CTD data

Abstract

Abstract. The volume, heat and freshwater transports in the Fram Strait are estimated from geostrophic computations based on summer hydrographic data from 1984, 1997, 2002 and 2004. In these years, in addition to the usually sampled section along 79 • N, a section between Greenland and Svalbard was sampled further north. Quasi-closed boxes bounded by the two sections and Greenland and Svalbard can then be formed. Applying conservation constraints on these boxes provides barotropic reference velocities. The net volume flux is southward and varies between 2 and 4 Sv. The recirculation of Atlantic water is about 2 Sv. Heat is lost to the atmosphere and the heat loss from the area between the sections averaged over the four years is about 10 TW. The net heat (temperature) transport is 20 TW northward into the Arctic Ocean, with large interannual differences. The mean net freshwater added between the sections is 40 mSv and the mean freshwater transport southward across 79 • N is less than 60 mSv, indicating that most of the liquid freshwater leaving the Arctic Ocean through Fram Strait in summer is derived from sea ice melt in the northern vicinity of the strait.In 1997

Does the East Greenland Current exist in northern Fram Strait?

“…• N in Marnela et al (2013), in Langehaug and Falck (2012) and in the present study as well as in the moored measurements of von Appen et al (2016) that the synoptic view of 79…”

“…Some observational studies locate the northern (Rudels et al, 2005). There is evidence from drifter data (Gascard et al, 1995), hydrographic surveys (Marnela et al, 2013), an inverse modelling study (Schlichtholz and Houssais, 1999) and a numerical ocean model (Kawasaki and Hasumi, 2016) evidence from model studies in Fram Strait is at present inconclusive as the northern limit of the recirculation, the strength of individual recirculation pathways and of the boundary currents varies between models (Maslowski et al, 2004;Aksenov 5 et al, 2010;Hattermann et al, 2016;Ilicak et al, 2016;Wekerle et al, 2017). This appears to be related to the resolution of the models and the bathymetry (Fieg et al, 2010).…”

“…• N recirculates from the eastern boundary currents in Fram Strait to the EGC in the west (Rudels, 1987;Manley, 1995;Marnela et al, 2013). North of 79…”

Recent advances in understanding the Arctic climate system state and change from a sea ice perspective: a review

“…As a long known general feature of Fram Strait flow, the East Greenland Current flows southward while the West Spitsbergen Current (WSC) penetrates into the Arctic Ocean. This Atlantic water returns in parts (2 Sv), due to a local recirculation (Aagaard and Greisman, 1975;Marnela et al, 2013). The remaining part, ca 2-4 Sv (Schauer et al, 2008, andBeszcynska-Möller et al, 2012) of the WSC proceeds eastwards along the continental slope in two different branches (Schauer et al, 2004).…”

A 4.5 km resolution Arctic Ocean simulation with the global multi-resolution model FESOM1.4

“…BSO AW has the effect to reduce the temperature of the AW layer, so the higher temperature and heat content in the Canadian Basin in LOW should be attributed to the larger amount of warm Fram Strait AW. Because the temperature of the BSO branch is similar after the atmospheric cooling over the continental shelves, the slightly lower volume transport through BSO in LOW (Table 1) due to surface cooling and starts to subduct under cold Polar Water, and a fraction of AW recirculates to the west and then southwards in different paths (Quadfasel et al, 1987;Gascard et al, 1988;Saloranta and Haugan, 2001;Marnela et al, 2013;5 de Steur et al, 2014). Strong variability associated with mesoscale eddies was observed in the Fram Strait (von Appen et al, 2016), which may play an important role in setting the AW recirculation (Hattermann et al, 2016).…”