Cross-slope flow in the Atlantic Inflow Current driven by the on-shelf deflection of a slope current. (October 2018)

• Record Type: Journal Article
• Authors: Porter, M.; Dale, A.C.; Jones, S.; Siemering, B.; Inall, M.E.
• Is Part Of: Deep sea research. Volume 140(2018)
• Page Start: 173
• Page End: 185
• Publication Date: 2018-10
• Subjects: Cross-slope flow -- Gliders, exchange -- Drifters -- Nutrients -- Nitrate flux; Oceanography -- Periodicals; Océanographie -- Périodiques; 551.4605
• DOI: 10.1016/j.dsr.2018.09.002
• Languages: English
• ISSNs: 0967-0637

Abstract

Abstract: We identify a newly described current, the Atlantic Inflow Current (AIC), a persistent pathway of Atlantic Water from the European Slope onto the Malin Shelf. Using drifters and gliders we examine the vertical and horizontal structure of the AIC and use Lagrangian statistics to quantify lateral mixing along its path. We estimate this current to have a transport of approximately 0.2 Sv, advecting 2.8 TW of heat onto the shelf (referenced to 7 °C) and 2.4 kT/day of the limiting nutrient, nitrate. This nutrient-rich AIC joins the Irish Coastal Current, continuing into the Minch and the outer Hebridean Shelf before ultimately entering the North Sea. The biological consequences of the influx of water masses and nutrients onto the shelf can range from altering primary production, and subsequent food web dynamics, to recruitment of fish larvae from oceanic water. A better understanding of the current dynamics described here is crucial for the assessment of shelf sea primary production and its impacts on carbon draw-down as well as recruitment for commercially important fisheries. Highlights: Slope water has been tracked on the European Shelf using drifters and gliders. The deflection onto the shelf is not captured in models. The slope water has a higher nitrate concentration that the shelf water, and supplies nutrients to the shelf.