As part of an experiment to study wind-driven coastal circulation, 17 hydrographic
surveys of the middle to inner shelf region off the coast of Newport, OR (44.65°N, from
roughly the 90 m isobath to the 10 m isobath) were performed during Summer 1999
with a small, towed, undulating vehicle. The cross-shelf survey data were combined with
data from several other surveys at the same latitude to study the relationship between
upwelling intensity and wind stress field. A measure of upwelling intensity based on the
position of the permanent pycnocline is developed. This measure is designed so as to be
insensitive to density-modifying surface processes such as heating, cooling, buoyancy
plumes, and wind mixing. It is highly correlated with an upwelling index formed by
taking an exponentially weighted running mean of the alongshore wind stress. This
analysis suggests that the front relaxes to a dynamic (geostrophic) equilibrium on a
timescale of roughly 8 days, consistent with a similar analysis of moored hydrographic
observations. This relationship allows the amount of time the pycnocline is outcropped
to be estimated and could be used with historical wind records to better quantify
interannual cycles in upwelling
