Seasonal dependence of surface wind stress variability on SST and precipitation over the tropical Pacific

The dependence of interannual variability of surface zonal and meridional wind stresses (tau (x) and tau (y)) on sea-surface temperature (SST) and precipitation over the tropical Pacific is examined using observed data. A strong seasonality in the dependence is found. In January, the largest SST and precipitation anomalies are located in the central to eastern and central tropical Pacific respectively. tau (x), anomalies in the southern central tropical Pacific and tau (y) anomalies in the northern tropical Pacific are highly correlated to both the SST and precipitation anomalies. In contrast, during July the largest SST and precipitation anomalies are located at the eastern and western tropical Pacific respectively. East of the dateline, tau (x) anomalies present little dependence on the SST anomalies. West of the dateline, tau (x) anomalies depend strongly on the precipitation anomalies that are not linked to the leading modes of SST.