Model simulations of the Gulf of Maine response to storm forcing

The storm response of the Gulf of Maine/Georges Bank region was investigated using the barotropic version (i.e. uniform density) of the Dartmouth 3-D nonlinear, finite element coastal ocean circulation model with quadratic bottom stress called QUODDY. A suite of model hindcast experiments for the period 4-18 February 1987 was conducted, in which the model was forced at the open ocean boundaries by the M2 semidiurnal tidal sea level and in the interior by realistic surface wind stresses featuring a strong 9-11 February nor’easter. Results for a reference model run with a time-space constant drag coefficient Cd of 0.005 captured more than 60 % of the observed sea level variance, but left large unexplained model/observed sea level differences, particularly during the storm. Model sensitivity testing to a realistic range of constant Cd values did not improve model results significantly. However, when atmospheric pressure was added to the surface forcing, significant reductions in the model/observed sea level differences were realized. 1. Background The Gulf of Maine is an inland sea that is separated from the Atlantic Ocean by several shallow offshore banks including Georges Bank (Figure 1). Thus the Gulf responds t