东海混浊海域悬沙浓度的三维数值模拟及与观测的比较

A THREE-DIMENSIONAL SEDIMENT TRANSPORT MODEL IN THE OFFSHORE AREA NEAR THE CHANGJIANG ESTUARY——A CASE STUDY

借助ECOMSED模式进行了东海混浊水海域三维悬浮泥沙输运的数值模拟,其中水动力模拟中考虑了潮汐,海流(包括黑潮,长江径流等)及风场的作用,输运模型中考虑了粘性泥沙的絮凝、粘性和非粘性泥沙的再悬浮等过程。另外,在沉积输运模式中,增加了波浪的作用,使沉积输运模拟更完善,并与2006年8月份在长江口外海域获得的走航断面及定点悬浮泥沙垂向剖面的观测资料进行了比较。模拟的年均悬沙浓度结果显示,悬沙浓度在水平分布上由近岸向外海浓度降低,123?E以东浓度低于10mg/L。泥沙高值区分布在长江口及杭州湾海域。模拟获得的垂向浓度剖面与观测结果吻合良好,基本实现对长江口外海域悬沙浓度三维分布的数值模拟。

Base on the ECOMSED model, a 3-D hydrodynamic and sediment transport model for the offshore area near the Changjiang Estuary in the East China Sea was developed in this study. The hydrodynamic module was driven by tide and wind as well as inflow and outflow （such as Kuroshio, Changjiang River runoff）. Aggregation and resuspension of cohesive sediments were considered by the sediment transport module, while resuspension of noncohesive sediments was included. Simulated suspended sediment concentrations （SSC）, which were accompanied with the wave module, were compared with observational data during the August 2006 in the East China Sea. The annual mean distribution of SSC illustrated that the sediment concentration declined from the coastal to the offshore area. SSC at east of 123°E was less than 10mg/L. The higher SSC mainly appeared at the Changjiang Estuary and the Hangzhou Bay. The calculation profiles of concentration were consistent with the observational data.