长江口深水航道工程对北槽盐度分布的影响

基于改进的三维数值模式FVCOM，聚焦于北槽盐度在工程一、二、三期建设过程中的变化情况.考虑径流、潮汐和风场的共同作用，数值模拟和定量分析在各工程阶段特征时刻和半月潮周期平均盐度分布特征.分析计算结果表明:一期工程后，等盐线显著下移.二期工程后，等盐线继续下移；1‰~5‰低盐水控制范围增大；中下段垂向混合变弱，部分时刻盐淡水混合类型从部分混合类型变成高度分层型.三期工程后，1‰~5‰低盐水控制范围继续增大；下段高盐水上溯，相比工程前有少许增加.

Effect of the deep waterway project on the salinities in the north passage of the Changjiang Estuary

Unstructured-grid Finite Volume Coastal and Ocean Model (FVCOM) has been applied on the north passage, Changjiang Estuary, to study the salinity distribution and its variations under the impacts of different phases of the deep waterway project (DWP). Driven by the same forcings of freshwater discharge, tide and wind, the spring-neap-averaged and typical tidal moment’s salinity distributions under different phases of DWP are simulated and analyzed The modeling results show that the isohaline has been significantly pushed downstream after Phase I, and continued moving eastward after Phase II. At the same time, the controlling region of isohaline 1‰~5‰ has smoothly increased and the vertical mixing effects seem be weakened from the middle to eastern parts of shipping channel. Strong stratification is revealed along the deep channel. After the Phase III, the controlling region of isohaline 1‰~5‰ still increases with the upstream direction. The onshore saltwater intrusion has significantly intensified as the increased baroclinic gradient force due to deepened eastern channel.