Enhancement of phytoplankton primary productivity in the southern East China Sea following episodic typhoon passage

Abstract

The enhancement of primary productivity (PP enh ) in the southern East China Sea (ECS) following 16 typhoon passages was investigated using ocean color data and a primary productivity model. PP enh tended to be higher when typhoons traversed slowly with trajectories that allowed strong southerly winds to prevail over Yonaguni Island. Such long‐lasting southerly winds were believed to push the Kuroshio current axis shelfward, enhancing the upwelling of nutrients, hence promoting new productivity (NP). The importance of long‐lasting southerly winds as a proxy for physical perturbations underlying PP enh was expressed by an empirical equation by which 88% of PP enh variation could be explained. Applying this equation, we assessed that typhoon passages accounted for a minimum of 0.6–11.8% of the ECS summer–fall NP, suggesting that typhoon passage over the southern ECS is an important phenomenon supporting NP in the ECS.