Acta Geographica Sinica ›› 1990, Vol. 45 ›› Issue (4): 387-398.doi: 10.11821/xb199004001

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Chen Xiqing   

  1. Institute of Coastal & Estuarine Research, East China Normal University, Shanghai
  • Online:1990-10-15 Published:1990-10-15

Abstract: Because the future global sealevel rise, if real, will exert a great impact on the coastal en-vironment, the Chinese scientists have shown great interests in the sealevel changes along the Shanghai coastal area where the natural environment and society are highly vulnerable to the sealevel changes. The long and early records from the tidal gauges, the geodetic levelling, the annual mean discharge data of the Changjiang River as well as data from other geologic achieve-ments allow the author to make an in-depth study on the issue of sealevel changes in the area. In recent years some Chinese scientists propose that the sealevel has been declining since 1950's along the coast of Shanghai, while other foreign scientists attribute the sealevel rise to the crustal and iso-static sinking. After a comprehensive analysis on the factors affecting the sealevel changes in the area, the author has reached the conclusion of sealevel rise in the Changjiang River mou-th in the past 7U years with the rate about lOcm/century which is comparable with that of g1o-bal sealevel rise. However, the increase of annual mean high tidal level in the same period is remarkably greater, reflecting the estuarine morphological and hydro-dynamical effect on the high-tidal level as the sealevel rises. The evidences suggest that the component of tectonic sink-ing accounts for only 1/3 or less of the regional relative RSL rise. In contrast to the viewpoint of some Chinese scientists that the sealevel has been declining since 1950's, the author finds that the sealevel has shown a rising trend since 1951 with a rate about 2.5 mm/year. It is pro-posed that the sealevel rise after 1951 is a continuation of sea level rise since the beginning of this century. These results will provide a valuable basis for the study of future sealevel chang-es and the long-range decision-making in the regional environment and engineering.

Key words: the Changjianq River mouth, sealevel change, coastal environment