On the relationship between the interannual and decadal SST variability in the North Pacific and tropical Pacific Ocean

Abstract

To address the relationship between the North Pacific and tropical SST anomalies on decadal and interannual timescales, we analyzed observed SST during the period 1950-2000. The SST variability in the North Pacific has two fairly well separated timescales: (1) decadal and (2) interannual, and each has a markedly different relationship with tropical variability. Both the decadal and interannual variability in the North Pacific is connected to the evolution of tropical SST variability with different lead-lag relationships. The decadal SST variability in the North Pacific is found to lead tropical decadal variability by approximately 5 ∼ 7 years; however, the interannual SST variability is in the North Pacific in equilibrium with the tropical interannual variability. It is also shown that the spatial structure of the decadal variability in the North Pacific is significantly different from the interannual variability.