| 摘要: |
| 【目的】为了探索黔东北受长江横切变线影响的暴雨特征和强降水形成原因，【方法】利用实况观测资料，NCEP1°×1°再分析资料，对近10年黔东北受长江横切变线影响的暴雨过程进行分类分析。【结论】结果发现（1）副热带高压西侧北上的西南暖湿气流与我国东北低涡槽南下的变性干冷空气在长江中下游-贵州北部交汇，使得中低层南北气流之间的横切变线维持。但地面上影线系统不同，造成暴雨落区、强度存在差异。（2）第一类暴雨地面受低压影响，在充足的水汽和强的热力不稳定层结条件下，中低层强动力抬升及边界层锋生作用，强降水在地面辐合线与低层切变线叠加区域发生发展，雨强≥50 mm/h，50 mm≤24h降雨量＜100 mm ；第二类暴雨地面受海上高压后部偏东气流影响，在充足的水汽、强的动力抬升和弱的热力不稳定层结条件下，强降水在低层切变线附近及地面偏东气流里发展，暴雨范围较广，20 mm≤雨强＜50 mm/h，24h降雨量局地≥100 mm。 |
| 关键词: 切变线;暴雨;特征;黔东北 |
| DOI： |
| 投稿时间：2023-11-14修订日期：2024-03-14 |
| 基金项目:贵州省气象局研究型业务关键技术攻关团队（QHLSSLJ[2022]-05）：铜仁市短历时暴雨监测预警技术研究，贵州省气象局省市联合基金（黔气科合SS[2023]31号）：暴雨相似个例智能识别雨预报系统研究，铜仁市科技计划项目（铜市科研[2022]）44号）：偏东气流与地形相互作用对梵净山暴雨强度及落区的影响分析，贵州省铜仁市气象局暴雨预报研究团队 |
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| Analysis on the characteristics of two types of rainstorm affected by the cross-shear line of the Yangtze River in Northeast Guizhou |
| Yang Qun,Ran Guangjing,Li Xijing,Xiang Nan,Lyu Chunyan |
| (Tongren Meteorological Bureau of Guizhou Province) |
| Abstract: |
| [Objective] In order to explore the characteristics of heavy rainfall and causes of heavy precipitation formation in northeast Guizhou affected by the transverse transform line of the Yangtze River. [Method] Using the real observation data and NCEP 1°×1° reanalysis data, the rainstorm processes affected by the transverse transform line of the Yangtze River in northeast Qianjiang in the past 10 years were categorized and analyzed. [Conclusion] The results show that：(1) The warm and humid southwestern air flowing northward from the western side of the subtropical high pressure and the degenerate dry and cold air flowing southward from the northeastern low vortex trough converge in the middle and lower reaches of the Yangtze River and in northern Guizhou, making the cross-shear line between the north and south flows in the lower and middle layers maintained. However, different systems of shadow lines on the ground caused differences in the area and intensity of rainstorms.(2)The first type of heavy rainfall is influenced by low pressure. Under sufficient water vapour and strong thermally unstable stratification conditions, strong power lifting in the middle and lower layers and boundary layer fronts, heavy precipitation occurs and develops in the area of superposition of the surface convergence line and the low-level syncline, with rainfall intensity ≥ 50 mm/h and 50 mm ≤ 24h rainfall < 100 mm; The second type of storm surface is influenced by the easterly flow behind the offshore high pressure. Under the conditions of sufficient water vapour, strong dynamic lifting and weak thermally unstable stratification, heavy precipitation develops in the vicinity of the low-level shear line and in the easterly airflow at the surface, with a wide range of heavy rainfall, 20 mm ≤ rainfall intensity ＜50 mm/h, and ≥100 mm in localities for 24h rainfall. |
| Key words: Shear line; Heavy rain; Characteristics; The Northeast of Guizhou Province |
