An SST anomaly dipole in the northern subtropical Pacific and its relationships with ENSO

This study examines the links between tropical and subtropical sea surface temperature (SST) anomalies in the Pacific Ocean during ENSO (El Nino-South ern Oscillation) events. A long-term simulation by the UCLA coupled atmosph ere-ocean general circulation model is used. It is found that a zonally-ori ented SST anomaly dipole in the subtropical Pacific develops almost simulta neously with and is closely related to tropical ENSO events. The dipole is located east of the dateline between 20 degrees N and 40 degrees N and cons ists of an anomaly center off the coast of the North America and another an omaly center with opposite sign further to the west. It is demonstrated tha t this dipole feature is primarily driven by anomalous surface heat fluxes associated with the altered atmospheric circulation during ENSO events.