Satellite-driven Observational and Numerical Modeling Evidence of Negative Surge by Typhoon Talim 2017 over the Shelf of the East China Sea

Typhoon Talim was generated in the Northwest Pacific (NWP), entering into the East China Sea (ECS) off the Northeastern Taiwan after propagating northwestward, and then slowly turning northeastward before finally crossing the Kyushu, Japan, from Sep. 9 to 17, 2017. Satellite altimeter data extraordinarily revealed the presence of negative surge in the ECS, while it was greatly masked by warm and cold eddies dominant in the open ocean of the NWP, south of the Ryukyu Islands. This fact was confirmed by a numerical modeling which shows that the negative surge appears in the ECS off the northeast Taiwan as the typhoon Talim approaches the shelf. It seems that the negative surge is driven by typhoon Talim associated with the Ekman divergence forced by strong positive wind stress curl formed around the typhoon center.