Circulation of the eastern North Atlantic and north‐west European continental shelf – a hydrodynamic modelling study

Abstract

As part of the interdisciplinary investigation of Calanus finmarchicus migrations between oceanic and shelf areas off north‐west Europe (the ICOS project), a three‐dimensional, prognostic baroclinic circulation model system, consisting of a coarse and a nested fine scale model, was constructed. The aim was to simulate the flow fields around Iceland, the Faroe Islands and the north‐west European continental shelf and slope, including the northern North Sea. The coarse scale model covered the northern North Atlantic and provided the far field flow to the finer scale model. The latter was initialized and forced with climatological seasonal (winter and spring) means of temperature, salinity, river run‐off, and other parameters necessary for the calculation of heat fluxes. Seasonal average simulations of flow and hydrographic conditions were performed, together with simulations of specific scenarios of uniform wind forcing from different directions. A feature common to all the results was a topographically guided northwards flow along the continental shelf edge, with a southwards counter‐flow in the vicinity of the Faroe–Shetland Channel. The extent and strength of the shelf edge current, of its counter flow, and of the re‐circulation cell in the northern North Sea, were dependent on the prevailing wind direction. The modelling results were consistent with the accepted circulation patterns in the area, and a comparison with field measurements in the Faroe–Shetland Channel showed that the main characteristics of the flow were well replicated, although the estimated strength of the slope current was somewhat less than in the field observations.