甘肃庆阳突发性暴雨与系统性暴雨的对比分析

Comparative Analysis of an Abrupt Rainstorm and a Systemic Rainstorm in Qingyang of Gansu

为研究甘肃庆阳地区突发性暴雨和系统性暴雨成因及特征,给该地区的灾害性暴雨天气预报预警提供参考依据,本研究利用常规气象资料和诊断分析技术对比分析了庆阳地区2016年7月10日突发性暴雨和7月18日系统性暴雨过程。结果表明:(1)2次暴雨500 h Pa上都有低槽,均存在高空急流,且都上冷下暖,水汽均来源于孟加拉湾,中尺度云团都较为活跃,组织化程度较高;(2)主要影响系统"7.10"突发性暴雨是两高之间切变线、辐合线和低涡,范围较小,"7.18"系统性暴雨是东北低涡下滑冷空气、高原槽和低空急流,范围较大,持续时间较长。(3)"7.10"暴雨局地温湿条件更好,"7.18"暴雨水汽输送通道更畅通,辐合更明显,上升运动更强。(4)"7.10"暴雨较"7.18"暴雨具有更大的不稳定能量、更高的CAPE值和更强的垂直风切变,但垂直运动和辐合辐散均较弱。(5)"7.10"暴雨主要以孤立的对流性云团为主,云顶亮温很低,"7.18"暴雨主要以混合性云系为主,云顶亮温较低。

Based on the study of the causes and characteristics of an abrupt rainstorm and a systematic rainstorm in Qingyang, Gansu, the authors aim to provide references for the severe rainstorm weather forecast and earlier warning. The conventional meteorological data and diagnostic analysis technology were used to make comparative analysis of the ＂7.10＂ abrupt rainstorm and ＂7.18＂ systemic rainstorm in Qingyang. The results showed that： （1） the two rainstorms both had low slot at 500 hPa and upper level jet, as well as being upper-cold lower-warm, and the water vapor were from the bay of Bengal, the mesoscale cloud was more active with higher organization degree; （2） the main influencing system of the ＂7.10＂ abrupt rainstorm was the shear line, convergence line and the vortex between the two uppers, with a smaller range; ＂7.18＂ systemic rainstorm was northeast vortex deeline cold air, plateau trough and low-level jet, with a large range and long duration time; （3） the temperature and humidity conditions of ＂7.10＂ rainstorm was better, and ＂7.18＂ storm water vapor transport channel was more smooth, convergence was more obvious, and ascending motion was more stronger; （4） compared with the ＂7.18＂rainstorm, ＂7.10＂ rainstorm had greater instability energy, higher CAPE value and stronger vertical wind shear, but the vertical movement and the convergence divergence were weaker; （5） the ＂7.10＂ rainstorm was mainly dominated by isolated convective clouds with very low TBB; ＂7.18＂ rainstorm were mainly dominated by mixed cloud with lower TBB.