2013年5月7—10日永州连续性暴雨过程诊断分析

Diagnostic Analysis of a Persistent Rainstorm on May 7 to 10,2013 in Yongzhou

利用常规观测资料、NCEP/NCAR再分析资料(1°×1°)和区域站资料,对2013年5月7—10日永州连续性暴雨过程进行天气动力学、热力学诊断分析。结果表明:该次持续性暴雨过程是在高空槽、高低空急流以及地面前期暖倒槽后期弱冷空气共同影响下产生的;降水期间湿层深厚,中低层相互配合的比湿骤降陡升可能预示着一次暴雨过程中较强降水的发生,以及变化的幅度与降水的多寡有联系;水汽通量散度负值的发展高度对强降水有影响;垂直速度的发展高度、强度范围与降水量有一定关联;K指数,SI指数、CAPE等热力学指数与强降水有着较好的对应关系。

Using the data of conventional observation, NCEP/NCAR 1 ° × 1 °reanalysis and regional observation stations, we diagnostically analyzed the synoptics, dynamics and thermodynamics of a persistent rainstorm on May 7 to 10, 2013 in the Yongzhou area. The result is presented as follows. The rain resulted from a joint effect of an upper-level trough, jet streams at both upper and low levels and a warm, inverted trough that was followed by weak cold air. A wet layer was deep during the rain, sharp rise and fall of spe- cific humidity may indicate the occurrence of relatively intense episodes during a rainstorm. The height to which vertical velocity develops and the area it covers are somewhat related with the amount of rain. The thermodynamics indexes of K, SI and CAPE are well corresponding to intense rainfall.