South China Sea Annual Meeting 2023 (SCSAM)

59 / 2023-07-24 15:08:13

Kuroshio Cut-off Events East of Taiwan Island Enhancing the Vorticity in the Northern SCS during the 1998-2013 Global Warming Hiatus

Kuroshio cut-off, South China Sea, vorticity, global warming hiatus

Although the issue of the global warming hiatus from 1998 to 2013 is still under debate, the surface velocity of the Kuroshio is shown to decrease east of Taiwan Island but increase east of Luzon Island. In this study, we found a significant increase in the negative vorticity in the northern South China Sea (NSCS) induced by the cut-off events on the Kuroshio main path east of Taiwan during the global warming hiatus period. This is probably related to the weakening of the Kuroshio velocity east of Taiwan and the enhancement of the Kuroshio velocity east of Luzon Island. The Kuroshio to the east of Taiwan Island is affected by westward mesoscale eddies from the North Pacific Ocean. The main path of the Kuroshio is sometimes cut off by these eddies, causing the northward Kuroshio to be accumulated in the sea off the southeast of Taiwan Island. The upstream of the Kuroshio is forced to go westward through the Luzon Strait and enter the NSCS, increasing the local negative vorticity. Applying a composite analysis method, when the Kuroshio cut-off event occurred east of Taiwan Island, the negative vorticity in the west of the Luzon Strait increased by 45% during the global warming hiatus period compared with the other period.