Sea level rise at east asia coasts based on tide gauge analysis

Sea level rise will bring very high impacts to coastal area, including increased coastal erosion, increased flooding risk, more extensive coastal inundation, changes in surface water quality and groundwater characteristics and potential loss of life. IPCC (2007) announced the global average rate is 1.7±0.5 mm/yr for the 20^th century. However, this rate is highly non-uniform in the world ocean. The purpose of this study is to know the regional value in the East Asia area. Long-term and qualified records from fifty-eight tide stations collected by PSMSL are used in this study. The linear trend of the sea level changes by least square approach is applied. We confirm the high variation on the sea level rising rates in the study area. At China Bohai Sea, the sea level change is steady within the past few decades. However at the Yangtze River mouth, the rate is large. It is 6.2 mm/yr which is several times of the global average value. A turning trend of the sea level fluctuation is found at the tide stations in Taiwan Island. The average rate of sea level rise of all the fifty-eight tide stations is 2.77 mm/yr for the East Asia area. This is 1.6 times higher than global average. In addition, we find the high rising rates happen at the band of Festoon Islands. This verifies the vertical land movement may contribute to some percentage to the sea level rise. To know the quantitative value of the sea level rise for coastal zone management, all causes should be take into account to have the equivalent value of sea level rise. However, to understand the component of sea level rise induced from global warming of the earth, the vertical land movement should be considered.