海洋学报（中文版）
海洋學報（中文版）
해양학보（중문판）
ACTA OCEANOLOGICA SINICA
2015年
3期
114-125
,共12页
林益帆%戴志军%李为华%谢华亮%李九发
林益帆%戴誌軍%李為華%謝華亮%李九髮
림익범%대지군%리위화%사화량%리구발
水动力%悬沙%机制分解%南北槽分流口%长江口
水動力%懸沙%機製分解%南北槽分流口%長江口
수동력%현사%궤제분해%남북조분류구%장강구
hydrodynamics%suspended sediment%mechanism decomposed analysis%bifurcation of North and South Passage%Changjiang (Yangtze) Estuary
河口分流口的水沙变化过程是影响河口三角洲发育的核心环节，对下游河势的稳定起着关键性的作用。本文通过对北槽二、三期工程前后的南北槽分流口河段洪季大潮期间的同步水沙观测数据进行分析，以探讨长江口深水航道工程整治对分流口水沙过程的影响。结果表明：（1）北槽二期工程到三期工程后，分流口洪季以落潮优势流、优势沙为主的格局基本没有发生改变，但南槽优势流、优势沙出现略有变大，而北槽略有变小现象；（2）分流口洪季的水体输移主要受控于欧拉余流的变化，除北槽入口段水体净输移量一直较小外，其他河段在二、三期工程实施期间均有大幅提升，其中斯托克斯余流变化不大，拉格朗日余流与欧拉余流变化相一致，南槽呈波动状上升，北槽先增后减；（3）在二期到三期工程期间，北槽分流比明显减小，入口段落潮流速减小，含沙量较高，水体输移量降低，输沙强度减弱，由此导致二期工程以来北槽入口河段淤积强度加重。
河口分流口的水沙變化過程是影響河口三角洲髮育的覈心環節，對下遊河勢的穩定起著關鍵性的作用。本文通過對北槽二、三期工程前後的南北槽分流口河段洪季大潮期間的同步水沙觀測數據進行分析，以探討長江口深水航道工程整治對分流口水沙過程的影響。結果錶明：（1）北槽二期工程到三期工程後，分流口洪季以落潮優勢流、優勢沙為主的格跼基本沒有髮生改變，但南槽優勢流、優勢沙齣現略有變大，而北槽略有變小現象；（2）分流口洪季的水體輸移主要受控于歐拉餘流的變化，除北槽入口段水體淨輸移量一直較小外，其他河段在二、三期工程實施期間均有大幅提升，其中斯託剋斯餘流變化不大，拉格朗日餘流與歐拉餘流變化相一緻，南槽呈波動狀上升，北槽先增後減；（3）在二期到三期工程期間，北槽分流比明顯減小，入口段落潮流速減小，含沙量較高，水體輸移量降低，輸沙彊度減弱，由此導緻二期工程以來北槽入口河段淤積彊度加重。
하구분류구적수사변화과정시영향하구삼각주발육적핵심배절，대하유하세적은정기착관건성적작용。본문통과대북조이、삼기공정전후적남북조분류구하단홍계대조기간적동보수사관측수거진행분석，이탐토장강구심수항도공정정치대분류구수사과정적영향。결과표명：（1）북조이기공정도삼기공정후，분류구홍계이락조우세류、우세사위주적격국기본몰유발생개변，단남조우세류、우세사출현략유변대，이북조략유변소현상；（2）분류구홍계적수체수이주요수공우구랍여류적변화，제북조입구단수체정수이량일직교소외，기타하단재이、삼기공정실시기간균유대폭제승，기중사탁극사여류변화불대，랍격랑일여류여구랍여류변화상일치，남조정파동상상승，북조선증후감；（3）재이기도삼기공정기간，북조분류비명현감소，입구단락조류속감소，함사량교고，수체수이량강저，수사강도감약，유차도치이기공정이래북조입구하단어적강도가중。
The water and sediment change of the bifurcation mouth is one of the key parts to influence the estuarine delta formation ,w hich is a determinative controlled factor on the stability of the dow nstream river situations . Here ,based on the flood season water and sediment data observed synchronously in the bifurcation mouth between North and South Passage (BMNSP) during the operations of the second and third phases of the Deep Water Chan‐nel Project (DWCP) in the Yangtze Estuary ,impacts of DWCP on hydrodynamics and sediment dynamics of the BMNSP were discussed .The results can be summarized as follows:(1) There had been almost no changes for the situation of both the ebb flow and ebb sediment dominance located at the BMNSP ,even though the operations of DWCP had experienced time span from the second to the post‐third phase .However ,the coefficients of both the ebb flow and ebb sediment dominance of the upstream mouth in the South Passage showed an obvious change from low values in the second DWCP to high values in the third DWCP during the flood season .The corresponding co‐efficients of both the ebb flow and ebb sediment dominance in the North Passage showed inverse changes comparing with those in the South Passage .(2) The Euler residual flow in the flood season could directly determine the flow transport of the BMNSP .During the second and third phase of the DWCP ,average transport discharge of the BMNSP was enhanced except the upstream of the North Passage where the average transport discharge still re‐mained low .The change of the Lagrange residual flow of the BMNSP was similar to that of the Euler residual flow .However ,the Stokes residual flow of the BMNSP has remained minor changes .(3) Due to the decreased ebb current velocities ,increased suspended sediment concentrations ,decreased flow transportation and weaken sediment transport rate of the upstream mouth of the North Passage from the second to the post‐third DWCP ,it could be the main reasons to induce the aggravation of accretions in the upstream mouth of the North Passage .
