1569—1980年长江口盐淡水混合区时空演变特征  

Spatio-temporal change characteristics of saline-fresh water mixing zone in the Yangtze River Estuary from 1569 to 1980

作　　者：鲍俊林[1] 高抒[2] BAO Junlin;GAO Shu(Center for Historical Geographical Studies,Fudan University,Shanghai 200433,China;School of Geographic and Oceanographic Sciences,Nanjing University,Nanjing 210093,China)

机构地区：[1]复旦大学历史地理研究中心,上海200433 [2]南京大学地理与海洋科学学院,南京210093

出　　处：《地理学报》2025年第3期742-757,共16页Acta Geographica Sinica

基　　金：国家自然科学基金项目(42371232);上海市教育委员会科研创新计划重大项目(2021-01-07-00-07-E00123)。

摘　　要：盐淡水混合是长江口重要水文现象,与生态安全息息相关。基于方志、盐志、舆图及海图资料的考证,采取定量与定性相结合分析方法,探讨长江口沿岸制盐、围垦活动与盐淡水空间分布演变的关系,旨在揭示16—20世纪长江河口段盐淡水混合区百年尺度的变化过程和机制。结果表明:①16世纪以来长江河口向海扩张、河道分汊、口门束窄,推动盐淡水混合区持续外移,并在南北支沿岸表现出差异性;②南支盐淡水混合区上界在明隆庆三年到万历二年间(1569—1574年)位于施翘河口—吴淞口一线,清道光二十二年(1842年)移至铜沙浅滩,年均下移285.7 m;③16世纪以来长江口近岸段等盐度线呈现北支内切、南支下移的平面分布特征,主轴方向从S-N到SE-NW逆时针旋转,1569—1980年间旋转幅度总计54°;④长江口河势百年尺度的自然变化驱动了盐淡水混合区演变,而20世纪中叶以来人工围滩显著加速了河势演变及等盐度线的走向变化。面对长江口泥沙减少、海面上升趋势,工程驱动的河口几何形态变化将是影响盐淡水混合演变的主要因素。The mixing of saline-fresh water masses is an important hydrological phenomenon in the Yangtze River Estuary(hereafter Yangtze Estuary),which influences the regional ecological security.Here we use historical local gazetteer,historical records of salt industry,traditional maps and historical charts to establish the relationship between anthropogenic salt-making,reclamation activities and the saline water distribution patterns.Meanwhile,on the basis of a combination of quantitative and qualitative analysis,we attempt to reveal the spatio-temporal water mixing pattern and identify the evolution mechanism of the mixing zone of saline-fresh waters in the Yangtze Estuary from the 16th to the 20th century.Furthermore,the causes and effects of the above evolution process were discussed based on the principles of estuarine hydrology and geomorphology.The results show that:(1)Since the 16th century,in response to the seaward expansion of the Yangtze Estuary,the bifurcation and the narrowing of the Estuary have promoted the continuous downward movement of the salt and fresh water mixing zone,with differences between the northern and southern branches.(2)The upper boundary of saline-fresh water mixing zone in the southern branch was located at the line dividing Shiqiao Estuary and Wusongkou during the Longqing and Wanli periods(1569-1574)of the Ming Dynasty,and this line moved down to Tongsha Shoal during the Daoguang period(1842)of the Qing Dynasty,with an annual downward rate of 285.7 m/a.(3)Since the 16th century,the isohaline in the nearshore section of the Yangtze Estuary moved inwards within the northern branch and downward within the southern branch,with its main axis rotating counterclockwise from S-N to SE-NW,and a total reversal of 54°from 1569 to 1980.(4)The continuous migration of saline-fresh water of the Yangtze Estuary since the 16th century is a naturally driven evolution process.Since the late 20th century,with the driving of the engineering,the geomorphology change of the estuary has accelerated the natur

关 键 词：盐淡水混合 等盐度线 历史水文 多源资料 长江口 

分 类 号：P731.2[天文地球—海洋科学]