The Relationship between Sea Level Change of China's Coast and ENSO

Based on the data of coastal tide level in China and of satellite altimeter and sea surface temperature in offshore areas of the Chinese coast and equatorial Pacific, the relationship between the sea level variation in China and ENSO are investigated. The research results show that, sea level change shows a fluctuent ascending trend along the coastal region of China, and the average rise rate is 2.9mm/yr in recent 30 years which is higher than the global average. The coastal sea level of China presents prominent inter-annual variation and inter-decadal variation besides the seasonal variation. The significant periods are 2-3a, 4-7a, 9a, 11a and 19a, and the oscillation of 4-7a is the most prominent in spring, which amplitude is close to 2cm. In El Niño events, the coastal sea level of China was lower than those in normal years, and it was obviously affected by ENSO. Annual and semiannual amplitudes of sea level significantly decreased in El Niñoevents. The minimum values of annual amplitudes all appeared in El Niño years, but in different regions they happened in different years. In addition, the solar annual constituent Sa amplitude of Chinese coast is related with the strength of El Niño events. Response area and magnitude are bigger in strong events, and are smaller in weak events. There is a significant negative correlation between monthly mean sea level in offshore areas of the Chinese coast and SST in the central and eastern equatorial Pacific, and the correlation coefficient is -0.42. It also shows that sea level in offshore areas of the Chinese coast is negatively correlated with Nino4 and Nino3.4 indices.