黄河调水调沙期间黄河入海水沙的扩散与通量

CHARACTERISTICS OF DISPERSAL OF THE YELLOW RIVER WATER AND SEDIMENT TO THE SEA DURING WATER-SEDIMENT REGULATION PERIOD OF THE YELLOW RIVER AND ITS DYNAMIC MECHANISM

  • 摘要: 以2007年夏季黄河调水调沙期间黄河三角洲海域3断面连续站及渤海南部24个大面站观测的流场、温度、盐度及含沙量资料为依据,分析了调查区水沙扩散特征,计算了各连续站的拉格朗日余流及泥沙输送单宽通量。结果表明,黄河入海泥沙扩散范围非常有限,主要分布在南至莱州湾西南部、北至北纬38°附近离岸约20 km以内的带状沿岸区域;但黄河冲淡水出现大面积扩散,覆盖了整个莱州湾的北部和中部,最远可至龙口附近,黄河入海水沙扩散不同步。在现行河口和钓口流路废弃河口存在两个高浓度泥沙中心,分别对应于黄河入海泥沙和废弃钓口流路海域底质再悬浮产生的两个泥沙来源。河口及三角洲近岸切变锋的阻隔及辐聚作用,是大部分黄河入海泥沙沉积在河口及沿岸13 m水深以内的主要动力因素。受余流方向及水体垂向湍动较弱的影响,两个高浓度泥沙中心很少有泥沙交换。冲淡水的大面积扩散主要受表层余环流的影响。余流及悬浮泥沙通量计算显示,夏季黄河入海水沙在近岸主要向东北方向扩散。

     

    Abstract: Data of current velocity, water temperature, salinity and concentration of suspended sediment were collected from 3 time-series survey transects of 3 boats off the Yellow River delta and 24 grid survey stations in the adjacent Bohai Sea during water-sediment regulation period of the River. Based on the collected data,the dispersal characteristics of the river water and sediment to the sea were analyzed, and the residual current and sediment flux of the time-series stations were calculated. The results show that the dispersal area of the Yellow River sediment to the sea was basically limited within the coastal zone to 20 km from the coast, extending to the southwest of the Laizhou Bay in the south and to 38°N in the north. The diluted river water dispersed widely. Covering the north and middle parts of the whole Laizhou Bay, the diluted water could extend to the Longkou City at its farthest southeast end,indicating that the dispersal pattern of the river sediment was quite different from the water dispersal pattern. There were two centers with high sediment concentrations. One of them was located in the river mouth area, and the other was around the abandoned Diaokou River mouth area, corresponding to sediment from the river mouth and sediment from resuspension of the surface sediment in the abandoned river mouth, respectively. The barred and convergent effects of the tidal shear fronts near the river mouth and off the delta coast were responsible for the limited dispersal of the Yellow River sediment within 13 m of the water depth. The wide dispersal of the river diluted water was controlled by the surface residual currents. There was little sediment exchange between the two high sediment concentration centers due to the directions of the residual currents and weak vertical mixing. The residual currents and the sediment flux showed that the direction of the sediment dispersal was basically northeastward.

     

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