Local blocking flow pattern in a forced and dissipative nonlinear system
强迫耗散非线性系统的局域阻塞流型

The barotropic vorticity equation is reduced to a KDV one containing the terms of forcing and dissipation, of which a stationary solution is obtained. It describes a local blocking flow pattern developed under the joint action of nonadiabatic heating, dissipation, nonlinear advection and the linear dispersion. By using the KDV equation, three numerical integrations whose integrative time is longer than 60 model days are performed. The results show that a transient motional form can appear, in which exist low-frequency oscillations of strength of blocking high center, whose periods are about two weeks or one month, but the location of high center remains quasi- stationary.