2001年春季东中国海三维环流的数值模拟

本文基于2001年4月东中国海区域实测水文资料,应用三维有限元模式FEOM(Finite Element Ocean Model)对东中国海三维环流系统进行了数值计算分析。模式水平网格系统采用单节点线性三角形网格,垂向使用z坐标,观测温、盐度场通过客观分析法插值得到初始条件,分别进行了诊断计算和强诊断计算,计算结果表明:(1)改进逆方法可以很好地反演研究区域流函数和流量分布,为数值模拟提供优质可靠的开边界条件。(2)有限元模式在网格自由度方面和对研究区域的完整覆盖方面优势明显,高分辨率的垂向z坐标也可以较好地拟合海底地形,从而得到较高分辨率的三维数值模拟结果。(3)通过诊断计算,模拟再现了东中国海春季环流的多涡结构,分辨出了台湾暖流、黄海沿岸流、黄海暖流等流系。(4)比较诊断与强诊断两个计算结果,它们在定性上较为一致,在定量上有些差别,总体分布强诊断计算结果更为合理。

Three-dimensional circulation numerical simulation of the East China Sea during spring 2001

On the basis of observed hydrological data in the East China Sea during April 2001, a three-dimensional model—FEOM (Finite Element Ocean Model) was applied to perform numerical analysis on the circulation in this region. The model uses single node linear triangular mesh for the horizontal grid and z-coordinate in vertical direction. Objective analysis method was introduced to interpolate this data to all the nodes to obtain the initial temperature and salinity condition, preparing for numerical experiments running respectively by diagnostic and robust diagnostic calculation. The computed results show that: (1) Stream function and flux calculated from the modified inverse method can reveal the velocity distribution of the study area well, and it can provide reliable open boundary condition to this simulation. (2) The finite element model has obvious advantages in respects to grid degree of freedom and full coverage of the study area. The high resolution vertical z-coordinate can also fit well with sea bottom topography, resulting in higher resolution results of three-dimensional numerical simulation. (3) Through the diagnostic calculation, the multi-eddy structure of the spring circulation in the East China Sea is reproduced, and the flow system of the Taiwan Warm Current, the Yellow Sea Coastal Current and the Yellow Sea Warm Current are distinguished. (4) Diagnostic and robust diagnostic calculation results agree qualitatively, but there are still some differences. In terms of overall distribution, the structure of the robust diagnostic calculation is more reasonable.