Sensitivity of Sverdrup transport to surface wind products over the tropical North Pacific Ocean

Abstract

This study investigates the sensitivity of the Sverdrup transport to the NCEP/NCAR, ERA-Interim, CCMP, and QSCAT wind products over the tropical North Pacific Ocean during the period of 2000–2008. Our analyses show that all of the S-E transports in the reanalysis/analysis winds are northward in the band of 7–9° N except the QSCAT wind, which produces more realistic southward transport as shown in the meridional geostrophic transports (MGTs) calculated from WOA13 and Argo data. At 24° N, high-resolution wind products can better estimate the meridional transport in this region. At 8° N, although the CCMP has the same high resolution as the QSCAT, it fails to produce more realistic ocean circulation just as the coarse resolution wind products do there. The unrealistically large wind stress curl and small zonal wind stress in winter in reanalysis/analysis wind products account for this discrepancy with the QSCAT. This discrepancy also suggests that the model physics used in these reanalysis wind products is deficient in depicting the ocean circulation in this region, where the ocean fronts and eddy activity are both active.