地形演变对黄河口切变锋位置及盐度分布的影响

Influence of topography evolution on position of tidal shear front and distribution of salinity around Yellow River estuary

基于FVCOM三维海洋数值模式建立了黄河口水动力模型,通过实测资料对数值模型进行了验证。验证结果表明建立的模型能很好的反映研究区域的水动力特性。利用该模型的数值模拟较好地再现了黄河口切变锋现象,并对两种不同类型的切变锋的形成、传播和持续时间的规律进行了分析研究。利用历年来黄河口地形演变的大致规律对黄河口附近的水下地形进行了演变,发现地形对切变锋形成位置有一定的影响,例如随着地形向外海淤进,切变锋的位置也随之向外海移动。还研究了地形的变化对黄河口海域盐度分布的影响,发现随着地形的演变,低盐度海水分布的范围会随之变大。

A three dimensional numerical model based on the hydrodynamic module of FVCOM was established for Yellow River estuary. The model has been calibrated by observed data and proved to be suitable to reflect the hydrodynamic condition in the research area. This paper employed the model to simulate the shear front of Yellow River estuary and analyzed the formation,spread and duration of two different types of shear front. Subaqueous topography of Yellow River estuary was changed according to the variation of topography over past years. Tidal shear front has been modeled on the changed topography. The results show that the position of shear front moved from a shallow to a deep area due to the deposition of topography. The influence of topography evolution on the distribution of salinity was studied and the outcome illustrates that the distributed areas of low salinity became larger when topography was changed.