Observations of a Seasonal Jet-like Circulation at the Central North Sea Cold Pool Margin

Abstract

In June/July 1996, a survey of the offshore region between the north-east coast of England and the Dogger Bank was undertaken using towed and conventional profiling CTD's and satellite tracked drifters. Strong bottom fronts bounded a pool of cold, dense bottom water isolated below the seasonal thermocline. These features extend continuously for ∼500km along the 40m contour, from the Firth of Forth to the eastern end of the Dogger Bank. Geostrophic current estimates and drifter trajectories demonstrate the existence of persistent and narrow (10–15km) cores of cyclonic near-surface flow (cold bottom water to the left) with velocities in excess of 0·1ms−1. The results are consistent with a seasonal baroclinic flow skirting the north east coast of England which provides a direct pathway for material and fish larvae from coastal regions to the northern Dogger Bank and central North Sea.