We would like to thank Drs. Peter Gent and Mark Cane for providing the foundation of the upper-ocean circulation model, and to Drs. William Kessler, Julian McCreary, Zhengyu Liu, and Rui-Xin Huang for invaluable discussions. We wish to thank reviewers for their numerous comments and suggestions that helped to improve the original manuscript significantly. This research was supported by the National Oceanic and Atmospheric Administration through Grant NA 16RC022802, the TOGA Program on Seasonal to Interannual Prediction, and by the National Aeronautics and Space Administration through Grant RTOP 578-21-03.
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