AN ESTIMATE OF THE CLIMATOLOGICAL MEAN CIRCULATION IN THE WESTERN NORTH-ATLANTIC

In order to produce a long-term mean circulation pattern for the weste rn North Atlantic, geostrophic velocities have been calculated using a recently-assembled hydrographic database comprised of NODC station da ta from 1904-1990. The property fields generated from this database ar e smoothed on isopycnal surfaces and have a nominal resolution of one degree for the spatial domain of this study (34-42N, 48-66W). To refer ence the geostrophic velocities, SOFAR float data over the period 1972 -1990 are used. The flow fields from this calculation are compared to fields produced using an assumed level of no motion. The calculations employing float data yield a flow field with two strong northern cyclo nic gyres separated at similar to 56W, the approximate location of the New England Seamounts. The southern anticyclonic recirculation gyre i s larger and weaker with two weak cells embedded within it. Significan t downstream changes in transport result from the presence of the reci rculations, particularly the northern gyres.