Relative Sea-Level Changes in China Over the Last 80 Years

Abstract

Study of tide-gauge records from 32 stations shows that, in the last 20-80 years, relative sea level at 20 stations is rising and at 12 stations it is falling. This results not only from eustatic sea level rise but mainly from recent local crustal deformations or ground water withdrawal. Stations in subsiding deltas and coastal plains have rising sea level whereas those in uplifting blocks show falling sea level. Thus, the relative sea level changes in China differ considerably from place to place and a mean value for the whole country has little significance for the assessment of future coastal hazards. Records at two key tide gauge stations, Tanggu and Wusong, have been corrected for land subsidence and therefore do not reveal relative sea level changes in these localities. An unusually high fate of relative sea level rise (> 10 mm/yr at Tanggu, Wusong and Taixi) is chiefly triggered by over-pumping of ground water. In order to mitigate disaster brought on by future sea level rise, strict measures should be taken to limit ground water withdrawal in coastal areas.