非线性临界层与副热带高压的形成

本文用无辐散正压涡度方程模拟非线性临界层。结果表明,在非线性临界层内,流函数场出现“Kelvin猫眼”现象。“猫眼”的流场呈准定常反气旋环流形势,“猫眼”的时空尺度、东移和形状变化与副热带高压有相似之处。因此,非线性临界层产生的“Kelvin猫眼”有可能是位于纬向东西风交界面附近的副热带高压形成的一种新的物理机制。

Nonlinear Critical Layer and Generation of Subtropical High

By a nondivergent barotropic vorticity equation,the nonlinear critical layer is simulated. The results show that in the nonlinear critical layer,a phenomenon of "Kelvin cat's eyes" occurs in the field of stream function,having a stream field of anticyclonic circulation.The temporal and spatial scale,eastward moving and shape changing of the "cat's eye" are similar to those of the subtropical high.It is then possible that "Kelvin cat's eyes" produced by the nonlinear critical layer is a new physical mechanism generating the subtropical high in the vicinity of the interface betWeen zonal easterlies and westerlies.