The seasonal variation of the low-frequency circulation in the Georges
Bank region is studied numerically by computing six bimonthly circula
tion fields subject to forcing from the barotropic M2 tide, mean baroc
linic pressure gradients, and mean wind stresses. The model is three d
imensional, diagnostic, and nonlinear, with quadratic vertical eddy vi
scosity that is stratification-dependent. Tidal forcing is imposed at
the boundary of the domain, and an extensive set of density and wind d
ata is used to determine climatological mean forcings. The magnitude o
f the M2 tidally rectified around-bank velocities and transports is se
nsitive to stratification influences on the eddy viscosity, with up to
a 50% intensification relative to computations which assume no influe
nces. The dependence occurs through both the local advective tidal str
ess terms and the large-scale barotropic pressure field. The six bimon
thly solutions (January-February, March-April, May-June, July-August,
September-October, November-December) indicate important contributions
from tidal rectification, baroclinic pressure gradients, and mean win
d stress to the seasonal intensification of the Georges Bank gyre. Tid
al rectification and baroclinicity are the dominant forcings, while wi
nd stress generates opposing around-bank flow and cross-bank surface d
rift in winter. Overall, the solutions are in approximate agreement wi
th observed Eulerian around-bank currents and transports, although the
re are both local and bank-wide discrepancies. The seasonal intensific
ation of recirculation around Georges Bank is well produced by the mod
el, with estimates of the recirculating transport increasing from unde
r 0.02 Sv (January-February) to over 0.13 Sv (September-October).