The relationship between sea level change of China’s coast and ENSO

Based on the tide level data of tide gauge stations and satellite altimeter,sea surface temperature,air pressure ,wind etc hydrological and meteorological data in the region of eastern equatorial Pacific,the relationship between the sea level change of China coastal area and ENSO are investigated. The research results show that the sea level of China coastal area is affected by ENSO obviously. Annual and semiannual amplitude of tide level decreased significantly in El Niño events. The minimum value of annual amplitude all appeared in El Niño years,but different regions happened in different years. In addition,the Sa tidal amplitude of China coastal in response to El Niño events related its strength. Response area and magnitude is bigger in strong events,response area and magnitude is smaller in weak events. In El Niño events,the sea level was lower than adjacent years,the MSL also shows prominent inter-annual and inter-decade variation besides the seasonal variation,the prominent terms are 2~3 a,4~7 a,9 a,11 a and 19 a,the oscillation of 4~7 a is the most prominent. There is a significant negative correlation between the MSL in China coastal area and SST in the central and eastern equatorial Pacific,it also shows negative correlation with Niño4 and Niño3.4 indices prominently. In typical El Niño event,the winter monsoon is strong in the winter half year before the occurrence of El Niño event,the pressure gradient is strengthened and the sea level is low in China coastal area. on the contrary,in the winter half year before the occurrence of La Niña event,the winter monsoon is weak,the pressure gradient is weaken and the sea level is high in the coast of China.