Study on Height Changes of Chinese Tide Gauges by GPS

The height changes of tide gauges directly influence ocean level observation.For research on ocean level variation in large region or globe,the land vertical displacement must be considered.In this paper,two sessions of GPS and absolute gravity observations in 2001 and 2003 are used to determine the horizontal and vertical motion of China coast in ITRF2000 and Eurasia frame.The difference between results of continuous observation and periodic observation is discussed.