振荡流场在海洋物质长期输运过程中的作用

The function of the oscillating tidal in the long-term transport

关于潮流对物质长期输运过程的作用,早期侧重于考虑潮流振荡部分的影响,潮致余流被揭示之后倾向于强调非振荡部分的影响。本文采用一个新的海洋物质长期输运模型,通过数值实验发现潮流的振荡部分,或者更一般性地说振荡流场对物质长期输运过程的影响,不仅可以与潮流的非振荡部分和涡团的扩散作用相比拟,而且在浅海通常大大强于后面二者。振荡流场的平流输运作用可以等效地参数化为扩散作用,这种参数化具有相当高的准确性,并且全场仅仅依赖于唯一的具有长度量纲的经验常数。研究还发现振荡流场长期输运作用数值模拟适用迎风差分格式,而不适用中心差分格式。

The oscillating tidal components were considered dominant in the long-term transport before the tide-caused residual current was discovered. People shifted to emphasize the non-oscillatory components later. With the application of a new long-term transport ocean model, the oscillating tidal components, or generally the oscillatory current, can exert on the long-term transport an effort comparative to that of the non-oscillatory components and the eddies, even far more in the shelf seas. The long-term transport effort of the advection of the oscillating current rnay be parameterized as a diffusion term. This parameterization is highly efficient with only one coefficient with length scale. In addition, this study has discovered that the up-wind differencing but not the central differencing is fit to simulate the long-term transport of the oscillatory current.