Abstract
AbstractThis study presents recent observations to quantify oceanic heat fluxes along the continental slope of the Eurasian part of the Arctic Ocean, in order to understand the dominant processes leading to the observed along‐track heat loss of the Arctic Boundary Current (ABC). We investigate the fate of warm Atlantic Water (AW) along the Arctic Ocean continental margin of the Siberian Seas based on 11 cross‐slope conductivity, temperature, depth transects and direct heat flux estimates from microstructure profiles obtained in summer 2018. The ABC loses on average (108) J m−2 per 100 km during its propagation along the Siberian shelves, corresponding to an average heat flux of 47 W m−2 out of the AW layer. The measured vertical heat flux on the upper AW interface of on average 10 W m−2 in the deep basin, and 3.7 W m−2 above the continental slope is larger than previously reported values. Still, these heat fluxes explain less than 20% of the observed heat loss within the boundary current. Heat fluxes are significantly increased in the turbulent near‐bottom layer, where AW intersects the continental slope, and at the lee side of a topographic irregularity. This indicates that mixing with ambient colder water along the continental margins is an important contribution to AW heat loss. Furthermore, the cold halocline layer receives approximately the same amount of heat due to upward mixing from the AW, compared to heat input from the summer‐warmed surface layer above. This underlines the importance of both surface warming and increased vertical mixing in a future ice‐free Arctic Ocean in summer.
Highlights
Warm water from the Atlantic provides the main source of oceanic heat for the Arctic Ocean and could melt the entire ice cover if released to the surface (Aagaard et al, 1987; Nansen, 1902; Rippeth et al, 2015; Rudels et al, 2012; Turner, 2010)
This study presents recent observations to quantify oceanic heat fluxes along the continental slope of the Eurasian part of the Arctic Ocean, in order to understand the dominant processes leading to the observed along-track heat loss of the Arctic Boundary Current (ABC)
We investigate the fate of warm Atlantic Water (AW) along the Arctic Ocean continental margin of the Siberian Seas based on 11 cross-slope conductivity, temperature, depth transects and direct heat flux estimates from microstructure profiles obtained in summer 2018
Summary
Warm water from the Atlantic provides the main source of oceanic heat for the Arctic Ocean and could melt the entire ice cover if released to the surface (Aagaard et al, 1987; Nansen, 1902; Rippeth et al, 2015; Rudels et al, 2012; Turner, 2010). In the Barents Sea and north of Svalbard, the AW is warmer than the near-freezing polar waters and occupies the near-surface layer of the water column, delaying sea ice formation and melting ice that is advected into the region (Meyer et al, 2017; Smedsrud et al, 2013). This sea ice melt leads to a gradual cooling and freshening of surface waters, and subsequently to subduction of the eastward propagating AW.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
