Name

Johannes Sandang Dugstad, PhD student, University of Bergen, Norway

Title

Mass exchange of Atlantic Water with the Lofoten Basin derived from high-resolution Lagrangian simulations and Eulerian models

Abstract

The Atlantic Water in the Nordic Seas undergoes a substantial cooling and densification as it flows northwards towards the Arctic. The largest water mass transformation is observed to take place in the topographical depression west of the continental slope of Norway, the Lofoten Basin, due to a retention of relatively warm Atlantic Water which results in large surface heat losses. The Atlantic Water inflow to the basin has been previously attributed to mesoscale eddies that drift into the basin from the eastern continental slope. However, the spatial distribution, vertical structure and seasonal variations of the inflow has not been yet quantified. To address this issue, we first analyze historical surface drifter trajectories as well as volume and heat transport from an eddy-permitting ocean model (ROMS). We find that warm water is mainly entering the Lofoten Basin from the south at surface, while at deeper levels heat is transported into the basin by the help of eddy fluxes from the east. Next, we analyze a largest-to date deployment of  2D and 3D Lagrangian particles in the region integrated using output from a dedicated high-resolution ROMS model simulation. We estimate key regions of the inflow, identify the typical characteristics of these water masses and study how these characteristics changes geographically around the basin. In addition, we compare how the vertical and seasonal signal is represented in the 2D and 3D simulations.

Authors

Johannes S. Dugstad(1), Inga Monika Koszalka(2), Knut-Frode Dagestad(3), Ilker Fer(1), Pål Erik Isachsen(4), Joseph Henry LaCasce (4)

(1) Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research, Bergen, Norway, (2)  Department of Meteorology, Stockholm University, Stockholm, Sweden , (3) Norwegian Meteorological Institute, Bergen, Norway, (4) Department of Geosciences, University of Oslo, Oslo, Norway

Time

Thursday June 13th, 14:15

Place

Rossbysalen C609, Arrhenius laboratory, Svante Arrhenius väg 16C, 6th floor

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