Structure and Seasonal Variability of the Arctic Boundary Current North of Severnaya Zemlya

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Ruiz‐Castillo, Eugenio, Janout, Markus, Hölemann, Jens, Kanzow, Torsten, Schulz, Kirstin, Ivanov, Vladimir, 1 Alfred‐Wegener‐Institut Helmholtz‐Zentrum für Polar‐ und Meeresforschung Bremerhaven Germany, 3 University of Texas Oden Institute for Computational Engineering and Sciences Austin TX USA, 4 Lomonosov Moscow State University Geography Faculty Oceanology Department Moscow Russia
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: ddc:551.48; Arctic Boundary Current; seasonal transport variability; water mass transport; along‐slope current; Arctic; Arctic Ocean; Barents Sea; Laptev Sea; Severnaya Zemlya; Svalbard; Fram Strait; laptev
• Online Access: https://doi.org/10.1029/2022JC018677; http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11134

We assessed the spatial and temporal variability of the Arctic Boundary Current (ABC) using seven oceanographic moorings, deployed across the continental slope north of Severnaya Zemlya in 2015–2018. Transports and individual water masses were quantified based on temperature and salinity recorders and current profilers. Our results were compared with observations from the northeast Svalbard and the central Laptev Sea continental slopes to evaluate the hydrographic transformation along the ABC pathway. The highest velocities (>0.30 m s −1 ) of the ABC occurred at the upper continental slope and decreased offshore to below 0.03 m s −1 in the deep basin. The ABC showed seasonal variability with velocities two times higher in winter than in summer. Compared to upstream conditions in Svalbard, water mass distribution changed significantly within 20 km of the shelf edge due to mixing with‐ and intrusion of shelf waters. The ABC transported 4.15 ± 0.3 Sv in the depth range 50–1,000 m, where 0.88 ± 0.1, 1.5 ± 0.2, 0.61 ± 0.1 and 1.0 ± 0.15 Sv corresponded to Atlantic Water (AW), Dense Atlantic Water (DAW), Barents Sea Branch Water (BSBW) and Transformed Atlantic Water (TAW). 62–70% of transport was constrained to within 30–40 km of the shelf edge, and beyond 84 km, transport increases were estimated to be 0.54 Sv. Seasonality of TAW derived from local shelf‐processes and advection of seasonal‐variable Fram Strait waters, while BSBW transport variability was dominated by temperature changes with maximum transport coinciding with minimum temperatures. Further Barents Sea warming will likely reduce TAW and BSBW transport leading to warmer conditions along the ABC pathway. Plain Language Summary: We assessed the structure and seasonal variability of the flow and water masses of the Arctic Boundary Current (ABC) in the region north of Severnaya Zemlya. This current is important in the Arctic Ocean as it transports relatively warm and saline waters along the Eurasian Arctic continental slope. We quantified the flow, ...