CIRCULATION IN THE EASTERN NORTH PACIFIC - RESULTS FROM A CURRENT-METER ARRAY ALONG 152-DEGREES-W

Data from four, 2-3 year long current meter records, at 28 degrees N, 35 degrees N, 39 degrees N and 42 degrees N, along 152 degrees W in th e eastern North Pacific, are used to describe the variability found in mesoscale period (< 200 days) and long period (> 200 days) motions. E nergy in the mesoscale energy band of 40-200 day periodicity is found in the upper ocean at each location, generally decreasing to the north and with depth. The long period flow is not coherent among these loca tions. Record length mean velocities at 3-4 separate depths were used to provide estimates of reference level velocities for vertical profil es of geostrophic currents derived from historical hydrographic data. The vertical profile of measured east-west vertical shear agrees well with the geostrophically computed value; the north-south measured vert ical shear is not in as good agreement. Assuming a vorticity balance o f fw(z) = beta v, and with w(z=0) as the Ekman pumping, the vertical v elocity profiles were also calculated at 28 degrees N and 42 degrees N . Using these three-dimensional referenced vertical profiles of mean c urrents, an examination of the mean advection of density in the thermo cline revealed significant residuals in the net three-dimensional adve ction of density (or heat and salt) above 850 m at 28 degrees N and ab ove 240 m at 42 degrees N. These results are relatively independent of the reference level velocities. (C) 1997 Elsevier Science Ltd.