Interannual variability in the stratospheric-tropospheric circulation in a coupled ocean-atmosphere GCM

Relationships between the northern winter stratospheric and tropospheric circulations and the sea surface temperature (SST) simulated by a global coupled ocean-atmosphere general circulation model are investigated. Two modes are extracted for interannual variability of the zonal-mean zonal wind by an empirical orthogonal function analysis. The first mode is related with interannual variations of the stratospheric polar vortex. This mode has a significant correlation with the North Pacific SST through tropospheric circulation changes. The second mode is the variation of the tropospheric subtropical jet and is related with the simulated El Nino. Model results imply no strong relationship between El Nino and the polar vortex.