| Interannual and interdecadal variability of the equatorial Pacific are examined using a new 60-year monthly historical pseudo-stress data set. The monthly mean pseudo-stress fields (1930-1989) are assembled from Comprehensive Ocean-Atmosphere Data Set pseudo-stresses using a variation of Cressman's (1959) objective analysis scheme, climate basis functions obtained from the FSU pseudo-stress product (1966-1990) and a technique called Vector Group Renormalization. The new wind fields are used to force an ocean model (Kubota and O'Brien, 1984). Model estimates of tropical Pacific current and model upper layer thickness (ULT) variability are then obtained for the period of interest. Observed sea level and spatially averaged sea surface temperature (SST) anomalies are used to validate the hindcasts.; Interannual fluctuations in modeled and observed sea level fluctuations are compared at Galapagos and Truk, yielding Correlation (r) values of 0.73 and 0.71, respectively. The comparison of the interannual fluctuations in modeled ULT and observed SST anomalies, which were both spatially averaged over a subdomain in the eastern Pacific basin, yielded a correlation (r) value of 0.64.; Interdecadal fluctuations in eastern Pacific model ULT are found to be qualitatively consistent with those in the spatially averaged observed SST anomalies. Interdecadal variations are shown to play a significant role in modulating the amplitude of El Nino events. Comparison of interdecadal fluctuations in global mean land air temperature and eastern Pacific ULT suggests a connection between eastern Pacific and global mean land air temperature warming for interdecadal time scales. |
