On the sensitivity of Sverdrup transport estimates to the specification of wind stress forcing in the tropical Pacific


  • Mary C. Landsteiner,

  • Michael J. Mcphaden,

  • Joël Picaut


We use Sverdrup dynamics to estimate geostrophic transports between 20°N and 20°S in the tropical Pacific Ocean averaged over the period 1979–1981. Three wind stress products are used to force the model. Results are compared to geostrophic transports computed along expendable bathythermograph transects in the western, central, and eastern Pacific for the same period. Depending on the choice of wind stress, modeled transports may differ from the observations by a factor of 2 and, in some cases, flow is opposite to that observed. Possible limitations of the Sverdrup theory are discussed; however, we conclude that detailed and accurate simulation of the general circulation in the tropical Pacific is limited more by the uncertainties in presently available estimates of the surface wind stresses than by deviations from Sverdrup balance.