Abstract
Wind driven circulation in the North Sea is revisited with a specific
focus on locally modified winds and their impacts. We show for the first
time that local extrema of the wind stress curl (WSC), generated by
orography and ocean-atmosphere interactions, help regulate circulation
in the northern North Sea. While calculated transports are strongly
coupled with wind stress, which itself is driven by large-scale forcing,
transports through the Norwegian Trench are more strongly correlated
with the WSC field due to local extrema. Such WSC extrema regulates the
sub-mesoscale eddy activity around the Norwegian Trench. We conclude
that local modification of the WSC is a result of both orography and
ocean-atmosphere interaction along the frontal Norwegian coastline.
Ocean-atmosphere interaction is considered a potential mechanism
developing the WSC extrema. Our results show that local winds are more
important than previously documented, with important implications for
regional circulation likely to result from future changes to local
surface gradients, such as may arise from changing meteorological or
hydro-climatic forcing. These additional impacts on North Sea
circulation that may not be accountable from changes in wind stress
alone.