Ageostrophic transport in the upper layers of the tropical Atlantic Ocean

A test of the theoretical Ekman relation in the tropical Atlantic Ocean is performed by comparing estimated Ekman transport with observations collected along two transects symmetric about equator (6 degreesN and 6 degreesS). Ekman transport is calculated theoretically using ship winds and climatological data. Total ageostrophic transport is obtained by subtracting the observed geostrophic transports from the measured total transports using the data collected along the two transects. Along 6 degreesS, both the zonal mean ageostrophic transport and it's variability with longitude can be accounted for by the theoretical Ekman transport. Along 6 degreesN, the total ageostrophic and Ekman transports agree, but significant differences are found in the cumulative transport curves between the African coast and about 40 degreesW. These departures from theory may be related to the effect of advective terms in the Ekman relation and/or other ageostrophic motion at the reference depth for the comparisons. Begin typing abstract here.