Potential for decadal predictability in the North Pacific region

A Predictable Component Analysis (PrCA) has been applied to near-term forecasts of ocean-atmosphere natural variability within a global warming scenario. The most predictable pattern in the North Pacific region on decadal time scales for the period 1965-1999 is a clockwise movement of heat content anomalies, which is composed of the eastward propagation along the Kuroshio-Oyashio extension (hereafter KOE) region and the subsequent southwestward propagation along the subduction pathway through the subtropical region. Our results also suggest the important role played by the westward traveling Rossby wave north of the KOE region in determining the phase change of the Pacific Decadal Oscillation (PDO) during this period. A comparative study with different initial conditions demonstrates the importance of proper thermal constraints on the ocean subsurface, in conjunction with the Rossby wave dynamics, for the initiation of predictable patterns in the heat content anomaly. Citation: Sugiura, N., T. Awaji, S. Masuda, T. Toyoda, H. Igarashi, Y. Ishikawa, M. Ishii, and M. Kimoto (2009), Potential for decadal predictability in the North Pacific region, Geophys. Res. Lett., 36, L20701, doi:10.1029/2009GL039787.