TRANSPORT EVENTS WITHIN THE FAIR ISLE CURRENT DURING THE AUTUMN CIRCULATION EXPERIMENT (ACE)

Five distinct circulation regimes are proposed for the Fair Isle current west of Orkney and within the northern North Sea. Three wind-driven regimes occur during the summer months when much of the northern North Sea is stratified (SI, SII and SIII) while two occur during the winter (WI and WII). All five are imposed upon the non-wind-driven circulations observed during the summer (SO) and winter (WO) months. Five specific transport events during September and November 1987 are selected in order to demonstrate the varying response of the current to meteorological forcing and seasonal stratification. The observed variability of the volume transport observed during these events is related to the meteorological forcing and to the resulting storm surges seen in the residual sea levels from four tide gauges sited around the Scottish coast. A simple model of particle advection illustrates the effect transport variability may have on the fate of fish larvae and pollutants introduced into the Fair Isle current. It is found that such variability can result in patches of high concentration entering the North Sea from a constant source placed along the current path. © 1990.