极浅海域潮流数值模型

通过对以往的浅水环流数值模型进行改进，建立适用于极浅水域的且能达到较高分辨率的潮汐环流数值模型。模型的主要特点是：（１）通过改进海底摩擦项的表达式来克服传统的二次方律在极浅的潮滩区所产生的不稳定问题；（２）采用逆风格式处理动量方程中的平流项，有效地抑制由于岸边界移动引起的数值短波的扩散。结合老虎滩湾海上工程的需要，利用本模型进行一系列的数值模拟试验。经过实测资料验证表明，改进后的模型具有良好的稳定

A NUMERICAL MODEL OF TIDAL CURRENT IN EXTRA-SHALLOW WATERS

A high resolution tidal current numerical model suitable for extrashallow wate-rs was developed by improving the previous numerical model of shallow water ci-rculation. The main points of the improved model are: (1) The expression of the bottom friction terms in the momentum equations are modified in order to overco-me the instability resulting from the application of the traditional square law in the extra-shallow tidal flat area. (2) The up-wind scheme is used to deal with the ad-vection terms in the momentum equations, so that the dispersion of the numerical short waves due to the moving of the land-water boundaries is restrained effective-ly. A finite difference method is used to solve the model equation. The computatio-nal grid is staggered. The timestepping procedure is based on the implicit alternate direction approach. The thomas algorithm is used to solve the tridiagonal system.Agreement between the model results and the observed data in numerical modelling experiments carried out in Laohutan Bight indicated that the improved model has good stability and reproducibility.