黄土高原地带连续性暴雨特征分析

通过研究甘肃庆阳地区连续性暴雨的成因及特征,为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分析了庆阳地区2017年8月17—22日连续性暴雨过程。结果表明：(1)连续暴雨前期降水历时短,强度大,分布不均匀,突发性明显；中期持续时间较长,范围广,局地降水强度强,累计降水量较大；后期持续时间长,范围广,分布均匀,累计降水量大。(2)低空急流低层抬升和高空急流抽吸造成了连续性暴雨的发生发展。(3)中尺度云团较为活跃,组织化程度高,持续时间长。(4)前期大气处于极度高能不稳定状态,中期不稳定能量有所下降,后期不稳定能量急剧下降。(5)前期比湿突增明显,跃变值达4g/kg,且比中后期大。

Characteristics of Continuous Rainstorm in Loess Plateau Areas

This paper aims to study the causes and characteristics of the continuous rainstorm in Qingyang area of Gansu, and provide references for the severe rainstorm forecast and early warning in this area. The continuous rainstorm process in Qingyang from 17 to 22 August 2017 is analyzed by conventional meteorological data and diagnostic analysis technology. The results showed that: (1) the precipitation duration of the continuous rainstorm in earlier stage is short, intensity is large, distribution is uneven, and outburst is obvious. The medium duration is long, scope is wide, local precipitation intensity is strong, accumulative precipitation is large; In the later period, it has a long duration, wide range, uniform distribution and large accumulative precipitation. (2) low layer uplifting of low level jet and high-jet suction caused the development and maintenance of the rainstorm. (3) the mesoscale cloud cluster is active, with high degree of organization and long duration. (4) in the early stage, atmosphere is in a state of extreme high energy instability, and in the middle period, the energy of unstable energy decreases, and in the later stage, unstable energy decreases sharply. (5) specific humidity increase obviously in the early stage, jump value reached 4g/kg,and larger than the later period, the strong southerly airflow in the low layer of the atmosphere formed a strong upward draft of the synoptic scale..