Pacific Multidecadal Climate Variability in CCSM3

The Pacific multidecadal climate variability (PMV) is an important phenomenon that has significant economic and societal impact. It is not only of considerable scientific interest but also a central component for potential long-term climate prediction. In this study, the PMV in the Community Climate System Model version 3 (CCSM3) is investigated with a combined statistical and dynamical approach. Specifically designed sensitivity experiments are performed to explicitly identify the origin of the PMV. The results support a North Pacific origin for the PMV, with the tropical Pacific responding passively. The North Pacific originated PMV is able to significantly impact the tropical Pacific and other sectors of the globe through atmospheric teleconnections. A first mechanism of the PMV is advanced based on a more thothough analysis, characterized by a crucial role of the subpolar North Pacific. The analysis should help shed some light on the origin and mechanism of PMV in nature, and should be especially useful to researchers in climate change and variability.