【摘要】 利用常规气象观测资料、地面逐时降雨量、物理量场和雷达、卫星云图资料,对2011年9月5-6日陕西中部一次区域性暴雨的成因进行了综合分析,结果表明:这次区域性暴雨出现在连阴雨当中,覆盖了陕西中部和南部地区,具有降水强度弱、持续时间长、局地性不强的特点,属于稳定性降水。强降水是在大气层结对流稳定的条件下产生的,低层对流有效位能和高架的CAPE都是0 J·kg-1;分析条件性对称不稳定条件发现降水前期的垂直运动来自于锋面强迫以及锋面上的条件性对称不稳定,后期的垂直运动主要来自于锋面强迫。低层东路冷空气不仅起到冷垫的抬升作用,还增强了大气低层锋区和大气的斜压性,有利于暴雨的产生;卫星云图、雷达回波证实强降水主要是弱对流云带或层状云造成的;低层充沛的水汽条件、较强的锋区和水汽辐合是此类暴雨产生的主要原因。更多还原

【Abstract】 The course of a regional rainstorm from 5 to 6 September 2011 in the middle of Shannxi province is integrated analyzed by using the routine meteorological observation data,surface hourly precipitation,physical quantity field,radar and satellite cloud imagery data. The result shows that the regional rainstorm appears in continuous rain which covers central and southern Shaanxi,with characteristics of weak precipitation intensity,long duration and not much local. It is a steady precipitation. This strong precipitation occurred under the condition of stable atmospheric stratification convection;Lower and elevated CAPE are both 0 J·kg-1. By analyzing conditional symmetric instability conditions,it finds that vertical movement of the early precipitation comes from the forced fronts and conditional symmetric instability condition.,while the vertical movement lately mainly comes from forced fronts. The cold air form the east area in low level not only plays the role of rising cold wedge,but also enhanced the atmospheric baroclinicity and frontal zone at lower level. Above all,they are conducive to the generation of heavy rain. It is confirmed by satellite cloud imagery and radar echo that strong precipitation is formed by the weak convective cloud belt or stratiform cloud;Low level flush water vapor condition,strong frontal zone and vapor convergence are the main course of the rainstorm.更多还原