夏季长江冲淡水表层盐度分布的数值模拟

长江是亚洲第一大河,巨大的迳流流入东海后,与外海水发生湍流混合,使本海区温盐结构随其发生变化.众所周知,某海区的盐度场结构及其变化是取决于该海区盐量收支的平衡规律.然而,考虑到长江冲淡水区是口股水系交汇的海区,所以影响盐度场的因子众多而复杂.运用统计相关分析,虽然能给出各因子和海水盐度分布的某种程度的相关关系,但对长江冲淡水的动力结构及其混合过程并未揭示.为此,本文想通过对夏季长江冲淡水远岸段的表层平均盐度分布,给出一个可能的数字模式.为进一步探讨长江冲淡水的动力结构及其混合过程提供一些启示,以期对该区的认识乃至预报有所裨益.

THE NUMERICAL MODEL OF THE SUMMER SURFACE SALINITY DISTRIBUTION OF THE CHANG JIANG DILUTED WATER

The steady state advective-turbulent diffusion equation is solved for two dimensonal "jet-like flow" of the Chang Jing(Yang River) diluted area.If a transverse velocity is not zero,there is bimodal distribution and there appears to be some tendencies to attract the open sea water which has been found from the solved process.On the right side of the "jet-like flow" there is an anticyclonic gyre,and on the left side there is a cyclonic gyre.For the summer surface salinity distribution of the Chang Jing diluted water,a possible mathematical model was given.Compared with the observed value,the central part of the "jet-like flow" is consistent with the observed one,but at the boundary part the computed value is not consistent with the observed one.