中尺度数值模式的自适应网格设计

THE MESH DESIGNMENT OF MESOSCALE MODEL WITH CONTINUOUS DYNAMIC GRID ADAPTION TECHNIQUE

引进了自适应网格设计的方法。自适应网格生成技术基于变分原理，所生成的网格具有光滑性、一定程度的正交性和可调节网格疏密程度的优点。这种新技术可任意加密局地网格，从而达到以较小的计算量获得较高计算精度的目的。将自适应网格技术应用于ＭＭ４中，并用来模拟１９９２年６月１４日这次大范围暴雨过程。结果表明，采用自适应网格后计算稳定，２４ｈ降水预报得到明显改善。

A new technique named continuous dynamic grid adaption (CDGA) technique is introduced in this paper.In order to improve the accuracy of numerical solutions by making arbitrarily local grid close together and to avoid great increase of computational expense. Considering variable principle, the resulting mesh from CDGA technique has advantages of smoothness, orthogonality and the adjustmentability in cell volumes. Using the MM4 with CDGA technique, the simulation results of the heavy torrential rain event on June 14,1992, show that the modified model runs steadily, and the 24 hours rainfall forecast is evidently improved.