Research For Applicability Evaluation Of A Tide-induced Mixing Parameterization Scheme

Tidal wave's dynamic process has significant influence on the marine dynamic environment of China offshore areas.As a concomitant effect of tidal wave's dynamic process,tide-induced mixing's influence on the generation and maintenance of coastal circulation(especially the Yellow Sea circulation in summer),fronts and upwelling in China cannot be neglected.Currently,ocean numerical models lack the direct parameterization to characterize the temporal and spatial variations of tide-induced mixing.In this paper,a parameterization scheme which can reproduce the spatial and temporal characteristics of tide-induced mixing is adopted and applied to numerical model.The applicability of this parameterization scheme is evaluated by numerical experiments.This parameterization scheme is based on harmonic analysis method.It is universal for it does not need to add tidal forcing on the open boundary when considering the effect of tideinduced mixing.In addition,compared with traditional methods of adding tides,the integration step of the model can be further optimized by using this parameterization scheme,which is especially meaningful for the simulation and prediction of large regional and global ocean models.Based on POM(Princeton Ocean Model),a coupled wave-tide-current numerical model for China offshore seas is constructed in this paper and numerical experiments for tide-induced mixing are carried out.Based on the analysis of the temporal and spatial distribution of tide-induced mixing in different seasons in China offshore seas,the applicability of this parameterization scheme is analyzed and evaluated.The results show that tide-induced mixing has apparent controlling effect in near-bottom layer of shallow shelf seas,especially in season with strong stratification.But the effect of tide-induced mixing is slightly weaker in winter when vertical water column is uniform.The tide-induced mixing parameterization scheme adopted in this paper can make the numerical model describe the tide-induced mixing effect better and reproduce the circulation,temperature front and upwelling in China offshore seas reasonably.It is proved that this parameterization scheme is universal and can be widely used in other ocean models.