结果说明，1991年欧亚地区的基流不稳定性较强，且初始扰动结构有利扰动发展，因而通过能量频散在乌拉尔地区激发扰动并强烈发展，建立起阻塞形势。

• ?The result shows that, the instability of the 1991 basic flow in Eurasia region is stronger, and the initial perturbation possesses the structure of preferred growing perturbation. Therefore the disturbances are excited near Ural area through energy dispersion, then grow very rapidly and develop the blocking circulation.