Skillful Multiyear Prediction of the Kuroshio and Gulf Stream Jets and Eddy Activity
Shoichiro Kido, Masami Nonaka, Yasumasa Miyazawa
Abstract
Abstract The Kuroshio and Gulf Stream (GS), Northern Hemisphere warm ocean currents, have narrow bands of intense jets and vigorous eddies. While the importance of them in regulating physical and biological ocean systems and climate has been increasingly recognized, the operational predictability of year‐to‐year variations in these jets and eddies has not been quantitatively assessed yet. Through a series of experiments using an eddy‐resolving dynamical ocean forecasting system, here we show that observed year‐to‐year variations in the intensities of the jets and eddies in the Kuroshio Extension and GS regions can be skillfully predicted up to a lead time of about 2 years. Sources of predictability mostly come from initial ocean memories, and variations in local atmospheric conditions play a secondary role. Our results demonstrate that the observed multiyear variations in ocean jets and eddies in these regions are operationally predictable when ocean models are properly initialized with sufficient spatial resolution.