摘要
近70年来年平均海面趋势(已消去人为地面沉降)是上升的。其速率为10cm/世纪,与近百年来全球性海面上升速率相一致,而同期高潮位的上升速率为25cm/世纪,明显大于年平均海面的上升率。区域性的沉积基底构造下降在海面上升中所占的比重不超过1/3。1952年以来长江口海面变化亦是上升的,它是本世纪以来海面上升的延续。
Because the future global sealevel rise, if real, will exert a great impact on the coastal environment, 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 achievements 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 mouth in the past 70 years with the rate about lOcm/century which is comparable with that of global 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 sinking 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 proposed 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 changes and the long-range decision-making in the regional environment and engineering.
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
1990年第4期387-398,共12页
Acta Geographica Sinica
基金
国家教委博士后科学基金资助课题
关键词
长江口
海面
变化
研究
潮位
the Changjiang River mouth
sealevel change
coastal environment
