Preferred Time Scales of Pacific Decadal Variability During the Last Millennium Related to Volcanic Activity

Abstract Pacific Decadal Variability (PDV) plays a significant role in modulating the global climate change on decadal time scale. Although various reconstructions of the PDV have been developed for the last millennium, preferred time scales of the PDV and mechanisms behind them remain unresolved. Here, we combine a δ 18 O‐based PDV index derived through paleoclimate data assimilation (PDA) framework, with existing PDV reconstructions and climate models to identify the preferred time scales of the PDV. We show that the PDV in the last millennium is dominated by two modes of preferred time scales: multi‐decadal mode (50–70‐yr) and bi‐decadal mode (20–40‐yr). The former is prevalent during quiescent volcanic period; however, the latter is more common during periods with intensive volcanic activities. Our finding likely establishes an important role of volcanic activity in shaping the temporal structure of PDV during the last millennium, and highlights its potential contribution on decadal time scale.