Journal of Arid Meteorology ›› 2022, Vol. 40 ›› Issue (6): 909-921.DOI: 10.11755/j.issn.1006-7639(2022)-06-0909

• Study on rainstorm in arid region • Previous Articles     Next Articles

Local enhanced convective environment characteristics of an extreme rainstorm event in arid region of Northwest China

FU Zhao(), LIU Weicheng(), SONG Xingyu, XU Lili, SHA Honge, MA Li, CUI Yu   

  1. Lanzhou Central Meteorological Observatory, Lanzhou 730020, China
  • Received:2022-11-13 Revised:2022-12-20 Online:2022-12-31 Published:2023-01-10
  • Contact: LIU Weicheng


傅朝(), 刘维成(), 宋兴宇, 徐丽丽, 沙宏娥, 马莉, 崔宇   

  1. 兰州中心气象台,甘肃 兰州 730020
  • 通讯作者: 刘维成
  • 作者简介:傅朝(1967—),男,正研级高级工程师,主要从事强对流天气的分析研究.
  • 基金资助:


Extreme precipitation events in arid areas often lead to huge casualties and economic losses, the study on its evolution characteristics and formation mechanism can provide an important support for improving the accuracy of weather forecast. A rainstorm process occurred on 13 August 2022 in Jinta County of Gansu Province, which was located in arid region of Northwest China. Both daily precipitation and hourly precipitation broke through the historical extreme value at national meteorological station Hexi Corridor, and their extreme and local characteristics were significant. European Centre for Medium-Range Weather Forecasts (ECMWF) fifth-generation global atmospheric reanalysis (ERA5) and observation data were used in this paper to analyze the causes of the rainstorm. The results show that the rainstorm occurred in the north side of the stable South Asia high, and the dynamic forcing in the upper and middle level of troposphere was weak. The baroclinic system, the lower level shear line and surface cold front in front of the 500 hPa short-wave trough, was mainly located in the lower level. The continuous transport of low-level water vapor around the thermal over the Qinghai-Tibet Plateau provided the extreme water vapor condition and the moderate intensity stratification instability for the rainstorm area. In front of the formation of surface cold front, the regional difference of low-level water vapor transport in central and eastern parts of Jiuquan City formed an obvious wet frontal and dryline. The meso-γ-scale convective system which caused extreme short-term heavy precipitation was triggered by the dryline, and developed into deep moist convection leading to extreme heavy rain at the intersection point of the cold front and the dryline. The local characteristics were significant during the development of the dryline convective cells to deep moist convection.

Key words: arid region of Northwest China, local extreme rainstorm, dryline, frontogenesis secondary circulation, convective environment


干旱地区极端降水事件往往会造成巨大的人员伤亡和经济损失,研究其演变特征及成因有利于提升该类天气的预报准确率。2022年8月13日西北干旱区甘肃省金塔县出现暴雨天气,日降水量和小时降水量均突破河西走廊国家级气象站历史极值,极端性、局地性特征显著。利用欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)第5代全球大气再分析产品ERA5和实况观测资料对其成因进行分析。结果表明:暴雨出现在稳定的南亚高压北侧,对流层中、高层动力强迫较弱,斜压系统主要位于低层,为500 hPa短波槽前的低层切变线和地面冷锋;青藏高原热低压外围的低层水汽持续输送,形成了暴雨区局地性的极端水汽条件和中等强度的层结不稳定;地面冷锋前部,酒泉中东部低层水汽输送的区域差异形成了明显的湿度锋区和干线;造成极端短时强降水的中-γ尺度对流系统由干线触发,在冷锋和干线的交叉点处发展为导致极端暴雨的深厚湿对流,干线对流单体发展到深厚湿对流过程具有显著局地性特征。

关键词: 西北干旱区, 局地极端暴雨, 干线, 锋生次级环流, 对流环境

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