一种新的正定平流方案及其在水汽预报方程中的应用

本文在Smolarkiewicz(1983)[1]方案的基础上,提出了一种新的正定平流方案。它是无条件计算稳定的,形式简单、物理意义清楚且阻尼小,能够很容易地应用到多维模式中。文中通过一简单的平流试验,与其它几种有名的正定平流方案进行了比较;最后将这种方案应用到国家气象中心细网格有限区域业务预报模式水汽预报方程中,避免了原水汽计算方案产生严重负水汽的问题,并对24h降水预报场进行分析。

A NEW POSITIVE DEFINITE ADVECTION SCHEME AND THE APPLICATION OF IT TO THE MOISTURE EQUATION

Based on the Smolarkiewicz's scheme (1983),this paper proposes a new positively definite advection scheme which has a unconditional stibility, simple form, small implicit diffusion and clear physical sense. It can be easily applied to the multidimensional model. In this paper author compares the present scheme and some other known positive definite scheme by using a analytic test. Finally, the scheme is applied to the moisture equation in the FLM (the fine-mesh limited regional model of National Meteorological Center) and the result of the experiment indicates that the new scheme can avoid the problem of spurious generation of negative moisture and improve the 24-hour forecasting precipatation field.