Observed Sea Level Changes in the China Seas Since the 1990s

The current state of global sea level rise is a matter of great concern. This paper aims to analyze the variations in sea level within the China Seas using observational and reanalysis data. The climatological annual mean sea level reveals a distinct spatial pattern, characterized by higher levels in the south and lower levels in the north. Notably, the path of Kuroshio exhibits the highest sea level. The variability of sea level in the China Seas is predominantly influenced by seasonal changes, closely tied to the cycle of sea surface winds. Moreover, low-frequency sea level variations in the South China Sea exhibit substantial correlations with El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), while sea level variations in the East China Seas (including the Bohai Sea, Yellow Sea, and East Sea) exhibit some correlation with the North Pacific Oscillation (NPO) on interannual timescale. Observations from altimeters indicate a significant sea level rise across the China Seas since 1993, with an average rate of 3.8 mm/yr. The western coast of the Yellow Sea and East Sea, and the entire South China Sea has experienced particularly rapid sea level rise, with the highest rate exceeding 5 mm/yr. It is important to note that changes in mass dominate sea level variations on the continental shelves, while steric changes play a crucial role in the deep basin of the South China Sea.