南边界强迫的非线性临界层与副高的形成、维持和振荡

NONLINEAR CRITICAL LAYER FORCED BY SOUTHERN BOUNDARY AND GENERATION, MAINTAINING AND OSCILLATION OF SUBTROPICAL HIGH

用非线性准地转正压涡度方程模式，在南边界取定常强迫波，采用４种方案模拟了非线性临界层及其上激发的Ｋｅｌｖｉｎ猫眼，以确定热带的定常强迫对副高的形成、维持和振荡的影响。结果表明，南边界定常强迫仍在非线性临界层内激发行星尺度的准定常反气旋的Ｋｅｌｖｉｎ猫眼流场，猫眼的移动、强度和形状变化与夏季副高比较相似．而北边界定常强迫所得结果与夏季副高差异较大。因此，南边界所激发的非线性临界层上的Ｋｅｌｖｉｎ猫眼可能是夏季副高形成、维持和振荡的一种更为重要的新物理机制。文中还提出准定常行星波穿越副热带的非线性临界层的物理机制。

Using a quasi-geostrophic nonlinear barotropic vorticity equation, setting a stationary forcing wave along the southern boundary, and by means of four schemes, the nonlinear critical layer and exciting Kelvin cat's eyes on the layer are simulated. hence the affection of the stationary forcing for tropical belt on generation. maintaining and oscillation of substropical high is determined. It follows from the simulated results that in the nonlinear critical layer southern boundary forcing also excites a stream field of Kelvin cat's eyes, having the anticyclonic circulation with the planetary scale. Moving. strength and shape changing of the cat's eyes are similar to those of subtropical high in the summer, but the results obtained through a stationary forcing of the northern boundary differ greatly from the subtropical high in the summer. Thus. It is possible that Kelvin cat's eyes in the nonlinear critical layer excited by the southern boundary forcing is very important new physical mechanism for generation,maintaining and oscillation of substropical high. A physical mechanism to cross the nonlinear critical layer on the substropical belt for the quasi-stationary planetary waves is supposed.