Abstract: Three experiments whose integ ration times are longer than seven model months are performed. Results show that in the certain parametric region, the local thermal forcing cancreat the global transformation from the initial flow pattern characterized by two low troughs and two high ridges to the another flow pattern characterized by one low broad trough and one ridge, which has the stable property. The intensity, the extent, and the latitudial position of the local thermal for cing are the three factor saffecting the long-range evolution of large-scale flow pattern.