Shelf and slope dynamics offshore the west Svalbard continental margin

• Main Authors: Bensi, Manuel, Langone, Leonardo, Kovacevic, Vedrana, Ursella, Laura, Goszczko, Ilona, Aliani, Stefano, Rebesco, Michele, De Vittor, Cinzia, Relitti, F., Bazzaro, M., Deponte, Davide, Laterza, R., Mansutti, P., Lucchi, Renata, Wahlin, Anna, Soltwedel, Thomas, Skogseth, Ragnheid, Nilsen, F., Forwick, Matthias, Beszczynska-Moeller, A., Ivaldi, R., Demarte, M., Miserocchi, Stefano, Viola, A.
• Format: Conference Object
• Language: unknown
• Published: 2018
• Subjects: Arctic; Svalbard; Norwegian Sea; Svalbard Archipelago; Spitsbergen
• Online Access: https://epic.awi.de/id/eprint/45779/; https://hdl.handle.net/10013/epic.ad969458-e81e-49e9-a79b-fb10bdc6b88c

The large-scale circulation and dense water formation (DWF) in the Svalbard archipelago influence the thermohaline circulation in the whole Arctic. In particular, DWF depends on the rate of cooling and homogenisation of the Atlantic water along its northward pathway, brine rejection, boundary convection on shelves and slopes, and open-ocean convection. This study focuses on brine rejection, shelf convection and entrainment processes, which occur in the SW Spitsbergen area. Two short (~140m) moorings (named S1 and ID2), deployed at a depth of ~1040 m over the slope, collected multiannual (2014-2017) time-series in an area of interaction between the West Spitsbergen Current and the descending dense shelf plumes. Time-series revealed a large thermohaline and current variability between October and April. Data highlight the presence of Norwegian Sea Deep Water (θ = -0.90°C, S = 34.90, σθ = 28.07 kg m-3) influenced by occasional intrusions of warmer (up to +2°C), saltier (up to ~35), and less dense (down to 27.98 kg m-3) water during fall-winter periods. Interestingly, such intrusions occur simultaneously at both sites, despite their distance (~170 km), suggesting that winter meteorological perturbations play an important role in triggering dense shelf plumes, which collect particulate matter during their descent. Here we discuss the origin, timing, and role of such turbidity plumes in a period characterized by a general warming and ice reduction of the Arctic.