Pm. Poulain, ESTIMATES OF HORIZONTAL DIVERGENCE AND VERTICAL VELOCITY IN THE EQUATORIAL PACIFIC, Journal of physical oceanography, 23(4), 1993, pp. 601-607
Horizontal divergence and vertical velocity in the surface mixed layer
of the equatorial Pacific between 90-degrees and 150-degrees-W are es
timated from current measurements obtained from trajectories of freely
drifting buoys during 1979-1990. The 12-year averaged horizontal dive
rgence is predominantly meridional and has a maximum magnitude of 3-4
(X 10(-6) s-1) in a 20-km-wide latitude band centered on the equator.
Using the equation of continuity, this divergence corresponds to an up
welling velocity of 1.5-2 (x 10(-4) m s-1) at 50-m depth. The seasonal
variations of equatorial divergence are in good agreement with the lo
cal zonal wind stress.