The analysis of China Sea Level change
中国近海海平面变化特征分析

Merged altimetry sea level anomaly data over China seas for more than 14 years is analyzed using the Empirical Orthogonal Function method. The spatial and temporal characteristics of sea level variability over Yellow Sea (YCS), East China Sea (ECS) and South China Sea (SCS) are presented, respectively. Using normal Morlet wavelet transform, we analyzed the time-frequency characteristics of the main principal components. The results indicate that the spatial models of the principal components correspond to the circulations or oceanic currents in China seas. The prominent periodic signals in Yellow and East China Seas are the annual and two month cycles. The annual and semi-annual period signals are prominent in the East China Sea and South China Sea. But the semi-annual signal in East China Sea is instable. More importantly, a prominent quasi 540d signal is first identified in the East China Sea and South China Sea. The result of the tide gauge data of Xi Sha also proved that this signal existed.