Mm. Hall et al., CIRCULATION IN THE EASTERN NORTH PACIFIC - RESULTS FROM A CURRENT-METER ARRAY ALONG 152-DEGREES-W, Deep-sea research. Part 1. Oceanographic research papers, 44(7), 1997, pp. 1127-1146
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.