Secular Changes in the Tidal Amplitude and Influence of Sea-Level Rise in the East China Sea

The characteristics of secular changes in M-2 tidal amplitude in the East China Sea and the effect of projected sea level rise on tide amplitude were studied. Based on measurement data analysis, it was clarified that rapid sea level rise and M-2 tidal amplitude decrease had been observed at observatories that face the East China Sea around 1998. The change in M-2 tidal amplitude of the East China Sea by sea level rise was then studied in numerical experiments. And results showed that tidal amplitude increased on the west coast of the Korean Peninsula and the Taiwan Strait. A similar study was conducted for the Yatsushiro Sea and the Ariake Sea, which showed the highest M-2 tidal amplitude in Japan. As a result, it was found that M-2 tidal amplitude increased in the whole bays, which was against resonance tide theory. It was shown that mean sea level rise and M-2 tidal amplitude increase and decrease affected by sea level rise must be considered when predicting the risk of seashore disaster by global warming.