多重网格法在MM5自适应模式中的应用

Application of Multigrid Method in the Adaptive Mesh Model

将多重网格法应用于MM5中来加速自适应网格的生成,并用这种方法来模拟2002年6月17—18日发生在江南和华南的暴雨过程。试验表明:在收敛精度要求高的情况下自适应模式模拟结果的精度高于均匀网格模式,且多重网格法有助于提高运算效率。

The multigrid method, one of the most efficient iterative algorithm nowadays, possesses of the advantages of fast convergent speed and high accuratcy. Adaptive mesh technique aims at improving the accuracy of prediction by arbitrarily densifying the grids in areas where the gradient of quantities is large. By use of the muti-nested mesh method to speedup the simulation process, adaptive mesh technique is developed with MM5 model to simulate a rainstorm in south of Yangtse River from 17th to 18th June 2002. The result indicate that if the accurucy requirement of convergence is high, the amount of precipitation simulated by adaptive mesh model approaches the observation better than that simulated by uniform mesh model, and the multigrid method can raise the computing efficiency successfully, but if the accurucy requirement of convergence is very low, the multigrid method may be invalidated.