黄河调水调沙入海切变锋分析  

Preliminary Study on Shear Front off the Yellow River Mouth during the Water and Sediment Regulation

作　　者：徐丛亮 李金萍[2] 谷硕[2] 童林龙[3] 范骏[3] 

机构地区：[1]黄河河口海岸科学研究所,山东东营257091 [2]黄河水利委员会水文局,河南郑州450004 [3]河海大学港口海岸与近海工程学院,江苏南京210098

出　　处：《人民黄河》2014年第1期18-21,共4页Yellow River

基　　金：国家海洋公益科研专项(201105005)

摘　　要：黄河调水调沙期间在河口及邻近海域布设29个大面站施测垂线流速、温度、盐度、含沙量等,发现各因子垂线剧烈梯度变化后出现一个切变拐点,29个切变点连起来就形成一个曲面——切变锋面。锋面以下全部是底部海水层,锋面以上为上部淡水层;淡水不能向锋面以下渗透,故锋面以下温度、盐度垂线竖直,呈现海水性质;海水可以从锋面处向上入侵,故温度、盐度垂线梯度变化;锋面处含沙量最小,流速流向展现出上下两层径流与海流的切变;锋面位置起于近岸拦门沙坎底,沿主流与两侧逐渐升高与海平面平齐。3 000 m3/s流量时盐度锋面以上表层小于2.2%的低盐入海淡水大都分布在浅表层区域;入海泥沙由近到远、由粗到细快速絮凝落淤,超出2.2%线范围表层含沙量已小于10 mg/L,至距离口门前方7.9 km表层已是著名的黄蓝分界线,入海泥沙中低层最多运移到口门前方13 km、两侧6.35 km处。Based on vertical distribution data of current velocity, sediment concentration, salinity and temperature from 29 stations around the Yellow River mouth and the sea area nearby during a regulated discharge regime of the Yellow River, a shear inflection point appeared with the in- tense changing with vertical gradient of each parameter. There was a curved shear front surface formed by joining 29 shear points together. The salty water was distributed beneath the shear front interface and .fresh water upwards. The fresh water could not penetrate the shear front downwards so that the vertical distribution of salinity and temperature beneath the front interface was uniform. In opposite, the salty water could penetrate the shear front upwards so that the vertical distribution of salinity and temperature above the front interface was changing with gradient. The sediment distribution on the shear front interface was with the minimum sediment concentration and the current velocities along with directions appeared shear changing between two layers of runoff and tidal current. The location of the shear front began with the bottom of the near-shore mouth bar of the Yellow River and rose along the mainstream and both sides gradually until reaching to the sea level. Fresh water off the Yellow River mouth with 2.2% salinity mostly distributed in the shallow layer when the discharge was 3,000 m^3/s. The sediment flocculated and deposited quickly from far area to nearby region and also from coarse grains to fine sediment so that the sediment concentration in the surface area which exceeded the 2.2% salinity range was less than 10 mg/L. With the distance of 7.9 km to the river outlet, there was the famous boundary of blue sea water and yellow muddy runoff. The sediment from medium and lower layer could be transported to the area which was about 13 km beyond the river outlet and 6.35 km from both sides.

关 键 词：调水调沙 入海切变锋 黄河河口 

分 类 号：P332[天文地球—水文科学] TV882.1[水利工程—水文学及水资源]