Predictability of Multiyear Trends of the Pacific Decadal Oscillation in an MPI-ESM Hindcast Ensemble

While hindcast skill for the Pacific Decadal Oscillation (PDO) has so far been limited to a few years, we present hindcast skill for PDO trends up to 10 years ahead. Our analysis is based on an initialized hindcast ensemble with the global Max Planck Institute Earth System Model (MPI-ESM). As in previous studies, we find hindcast skill limited to a few years, when we first construct a lead-year time series, from which we second calculate the PDO. We find similar hindcast skill when we first calculate the PDO for each start year and second construct a lead-year time series. However, we find hindcast skill considerably increased, when we first calculate the PDO for each start year, second estimate multiyear trends, and third construct a lead-year time series. Our results suggest hindcast skill for the low-frequency variability of the PDO, which holds important implications for predictability analyses of other modes of long-term climate variability. ©2018. American Geophysical Union. All Rights Reserved