Revisited relationship between tropical and North Pacific sea surface temperature variations

The relationship between the tropical and North Pacific sea surface temperature (SST) variations is reexamined following the results of Deser and Blackmon (1995, DB95) based on a much longer period of data (1949-2010). As in DB95, the two leading SST modes, the El Nio-Southern Oscillation (ENSO) mode and the North Pacific mode, represent the SST variations in the Pacific domain before 1992. Considering the period after 1992, however, one needs to consider a new mode of SST variation along with the two modes mentioned to understand the relationship between the tropical and North Pacific SST variations. A new SST mode, known as the Warm Pool mode, exhibits a strong variance in the warm pool region and undergoes a phase shift after the mid-1990s, reflecting a warming in the warm pool region and a cooling in the central and eastern equatorial Pacific. It is found that the Warm Pool mode accompanies the North Pacific Oscillation-like atmospheric variability over the North Pacific. Through this teleconnection, the Warm Pool mode mostly shows a relationship between the warm pool SST and the associated North Pacific SST component and which has some similarities with the North Pacific Gyre Oscillation.