The response of East China Sea internal tides to ocean warming: intensified while maintaining seasonal contrasts

Abstract

The internal tide (IT) in the East China Sea (ECS) originates predominantly at the ECS shelf break and along ridges near the Ryukyu Island chain. Stratification in the ECS varies seasonally, contributing to corresponding changes in ITs. In recent decades, continual ocean warming has intensified stratification and may modulate IT. However, the effects of warming on the ITs in the ECS, including the seasonality, remain unclear. In this study, the evolution of IT energy and tidal mixing in response to ocean warming is explored using numerical simulations. The results indicate that ocean warming generally amplifies IT conversion and dissipation. However, the seasonal contrast in IT energetics is preserved because the stratification maintains its seasonal variability in a warming climate. Moreover, the contrast in tidal mixing across seasons also remains relatively stable. These findings may advance the understanding of hydrodynamic changes in response to warming.