气象2026，Vol.52Issue(6)：657-672,16.DOI:10.7519/j.issn.1000-0526.2026.031101
华北"25·7"暖区极端暴雨对流演变特征差异及环境条件分析
Differences in Convective Evolution Characteristics and Environmental Conditions of the July 2025 Extreme Warm-Sector Torrential Rain in North China
摘要
Abstract
With multi-source observations and ERA5 reanalysis data,this paper systematically analyzes an extreme torrential rain event that occurred in North China in late July 2025,and reveals the diversity in the initiation,organization and propagation mechanisms of mesoscale convective systems during three days with extreme rainfall(24,25 and 27 July)under a similar large-scale warm-sector background.Besides,the synoptic causes for the extreme torrential rain are investigated.The results show that this extreme rainfall event was characterized by significant extremity with heavy rainfall intensity and large accumulated precipitation amount.The multiple extreme precipitation centers within the southern warm-sector rainband posed big challenges to the forecasting operation.On 24 July,the convection initiated at the foothills,and the extreme rainfall was dominated by a"train effect"from backward-propagating and band-shaped convec-tion,which resulted in the most widespread rainfall area spanning mountains,foothills and plains.On 25 July,the convection originated in mountains,and the extreme rainfall was associated with a quasi-stationary system,leading to the localized precipitation.On July 27,the convection mostly initiated in plains and in-tensified after moving to the foothills.The extreme rainfall was related to the"train effect"from line-shaped convections,and the heavy precipitation occurred mainly in mountainous areas.On 24 July,the synoptic scale forcing was most significant.The strong and deep low-level jet(LLJ),coupled with oro-graphic lifting and sustained moisture transport,played a key role in the initiation and back-propagation of the convection.The convergent frontal zone formed by the outflow of the cold pool had a very important role in organizing the rainfall system and its expansion into plains.On 25 July,under the control of the subtropical high,a weaker and shallower LLJ restricted the downstream propagation of the convective sys-tem,making orographic lifting the dominant mechanism for the triggering and enhancement of heavy pre-cipitation.This was accompanied by a mesocyclone-like structure that produced the heaviest local hourly rainfall.On 27 July,under the weakest synoptic scale forcing,the convection was triggered by boundary layer easterly airflow and low-level weak convergence line.The mesoscale front area formed by the cold pool in mountainous areas and the warm ridge in plains provided favorable conditions for backward propa-gation.Moreover,the convergence and lifting of the southwest airflow in front of the terrain built powerful dy-namic conditions for the significant intensification of the convection moving from plains into foothills.关键词
极端暴雨/中尺度对流/低空急流/地形/冷池/中尺度锋区Key words
extreme torrential rain/mesoscale convection/low-level jet(LLJ)/terrain/cold pool/mesoscale frontal zone分类
天文与地球科学引用本文复制引用
陈双,符娇兰,陈涛,谌芸,刘倍峣..华北"25·7"暖区极端暴雨对流演变特征差异及环境条件分析[J].气象,2026,52(6):657-672,16.基金项目
灾害天气科学与技术全国重点实验室开放课题(2025KFA01)、国家自然科学基金联合基金项目(U2442204)、国家重点研发计划(2024YFC3012404、2024YFC3013005)、中国气象局能力提升专项(23NLTSZ007)和重大科技专项(2024-SF-A1)共同资助 （2025KFA01）
