摘要
利用常规天气观测资料、自动气象站气象观测资料、卫星云图以及天气雷达观测资料,对2005年5月30日发生在陕西省境内的飑线过程进行了探讨和分析,结果表明:地面到500 hPa各层影响系统的前倾结构,使前倾结构控制区内地区的不稳定度迅速加强,加之蒙古冷涡旋转分裂冷空气触发形成中β尺度对流系统(MβCSs),为飑线形成提供了前期动力和热力条件;地面流场和能量场的分析明显反映出了飑线在地面切变线后部,风向、风速辐合区前部。雷达产品分析表明飑线回波具有线状分布和发展快的特点,而且最大反射率与径向速度的最大值在飑线发生的时段内长时间相伴。当飑线回波上的单体进入“逆风区”时,发展更旺盛,不仅造成了灾害性的大风和冰雹,还造成了影响范围内的短时强降水。
By using the routine observational data, automatic meteorological station data, satellite cloud images and Doppler radar data, the squall line weather process occurred on May 30, 2005 in Shaanxi province was analyzed. Results show that the influence systems from surface to 500 hPa level presented slanting forward structure, which made the atmospheric instability under the control area suddenly enhance, and with the Mongolia cold cyclone rotation and cold air thrown from its tail, the meso -β scale convective system （MβCSs） was formed, and all those supplied the prophase dynamic and thermodynamic conditions for the squall line weather. Analysis of surface stream and energy fields obviously showed that the squall line occurred behind the surface shear line, and before the convergence area of wind. The Doppler radar data analysis showed that the squall line echo presented linear distribution and developing rapidly, moreover the maximums of composite reflectivity and radial velocity went with the squall line for a long time. When the squall line cell echo entered＂dead wind area＂, it developed more rapidly, which resulted in not only gale and hail but also shortly rainstorm.
出处
《干旱气象》
2006年第4期45-50,共6页
Journal of Arid Meteorology
关键词
飑线
不稳定度
最大反射率
逆风区
squall line
atmospheric instability
maximum composite reflectivity
dead wind area
