中文摘要：

采用WRF模式及其三维变分同化系统,对一次发生于南海高空越洋航线上的晴空颠簸（CAT）事件开展同化AMDAR资料的高分辨率数值模拟研究,探讨副热带高空急流与本次CAT的发生关系。通过对飞机航线上CAT发生时刻附近水平和垂直风场、气压场、温度场的模拟与分析,得出以下结论：（1）此次南海高空越洋航线上的CAT位置及周边区域存在明显的大气重力波活动;（2）影响此次CAT的大气重力波主要来源于副热带高空急流及非地转平衡;（3）急流区以及非地转平衡激发的大气重力波经过水平传播或垂直传播,通过扰动局地大气环境达到Kelvin-Helmholtz不稳定和急流南侧反气旋气流的惯性不稳定的两种机制使波形破碎,从而形成CAT。

英文摘要：

Based on the WRF model and its three-dimensional variational assimilation system, this paper did a high-resolution numerical simulation study with assimilated AMDAR data on a clear-air turbulence （CAT） on an overseas route above the South China Sea in order to explore the relationship between subtropical jet streams and the CAT. Through the simulation and analysis on the horizontal and vertical fields of wind, pressure and temper- ature, our work comes to the following conclusions ： （ 1 ） There were obvious atmospheric gravity wave activities on the spot of incidence and the surrounding area of the South China Sea CAT; （2） The atmospheric gravity waves affecting this CAT mainly came from a subtropical jet stream and ageostrophic flow; （3） The atmospheric gravity waves produced from the jet area and ageostrophic flow are transmitting horizontally or vertically to form the CAT through disturbing local atmospheric environment to the level of Kelvin Helmhohz instability and iner- tial instability in anticyclonic flow at the south side of jet streams, thus breaking waveform.