水汽方程积分计算格式的数值试验

NUMERICAL EXPERIMENTS ON CALCULATING SCHEME OF WATER EQUATION

该文把Ｅａｓｔｅｒ（１９９３）的水汽方程积分方案应用到球坐标的有限区模式（ＬＡＦＳ）中，并作了两组比较性试验．Ｅａｓｔｅｒ的方案是把水汽的通量方程和连续方程联立求解，在计算中不会出现水汽负值，而且稳定性好．本文所做的两组试验表明，Ｅａｓｔｅｒ的方案比ＬＡＦＳ的原方案所产生的计算性扩散小，因而降水预报更接近实况，但ＣＰＵ时间增加了１６％

Easter′s scheme, which is the modified version of Bott′s forward in time and positive definite numerical advection scheme, is described in this paper. Two groups of comparable experiments show that Easter′s scheme exhibits less numerical diffusion than the original scheme of LAFS, and therefore it won′t give excessive precipitation, which is consistent with observations, but needs 16% more CPU time.