摘要
【目的】探究2024年6月28日—7月1日滇西北罕见强降水天气过程的特征及成因。【方法】利用ERA5再分析资料、怒江州109个气象观测站点逐日降水数据,对强降水天气过程进行天气学诊断分析。【结果】1)冷空气与西南暖湿气流交汇区逐步南压,700 hPa强风速辐合,使得强降水自北向南发展。2)强降水期间对流层中低层水汽含量大,受地形阻挡作用低层水汽输送到中上层,怒江西侧水汽辐合强,提供充沛的水汽。3)强降水区为高层辐散—低层辐合,且在高能高湿环境下。怒江北部为强暖平流控制,利于上升运动,怒江南部中高层冷平流的侵入使未饱和空气趋于饱和,层结稳定度降低,为能量和潜热的释放提供有利条件,叠加地形强迫抬升作用,垂直上升运动加强。4)干冷空气与暖湿气流交汇使得扰动迅速增强,促进降水发展,强降水期间怒江IPV值超过0.5 PVU,局部可达0.8 PVU,强降水的发生与IPV扰动的发展有重要联系。【结论】滇西北地区地形复杂,为满足当下精准预报需求,预报时应充分考虑地形的影响。
To investigate the characteristics and causes of the extremely severe precipitation process in Northwest Yunnan from June 28 to July 1,2024,we conducted a synoptic diagnostic analysis of the severe precipitation process by using ERA5 reanalysis data and daily precipitation data from 109 meteorological stations in Nujiang Prefecture of Yunnan Province.The results indicate that:1)The convergence zone of cold air and warm,moist southwestern airflow gradually shifted southward with the convergence of strong winds at 700 hPa,leading the severe precipitation to develop from north to south.2)During the period of severe precipitation,the middle and lower troposphere were characterized by high moisture content.The orographic blocking effect facilitated the transport of low-level water vapor to the middle and upper levels,resulting in strong moisture convergence on the west side of the Nujiang River,thus providing abundant water vapor.3)The severe precipitation area had divergence in the upper troposphere and convergence in the lower troposphere,situated within an environment of high energy and high humidity.The northern part of Nujiang was dominated by strong warm advection,which was conducive to upward motion.The intrusion of cold advection in the middle to upper levels over the southern part of Nujiang caused unsaturated air to get to saturated,reducing the stability of the atmospheric stratification and providing favorable conditions for the release of energy and latent heat.Combined with the orographic forced uplift,the vertical upward motion was further strengthened.4)The convergence of dry cold air and warm moist airflow led to a rapid intensification of disturbances,promoting the development of precipitation.During the severe precipitation event,the isentropic potential vorticity(IPV)value in Nujiang exceeded 0.5 PVU,and even up to 0.8 PVU in some isolated areas,which indicates that there existed a significant correlation between the occurrence of severe precipitation and the development of IPV disturbances.Therefore,in the complex topography of the Northwest Yunnan,it is essential to fully consider the influence of terrain in the forecasting operation to make the forecast more accurate.
作者
蔡华成
肖金宜
李希燕
袁利平
CAI Huacheng;XIAO Jinyi;LI Xiyan;YUAN Liping(Nujiang Lisu Autonomous Prefecture Meteorological Office of Yunan Province,Lushui 673200,China;Gongshan Dulong and Nu Autonomous County Meteorological Station of Yunan Province,Gongshan 673500,China)
出处
《山地气象学报》
2025年第4期45-53,共9页
Journal of Mountain Meteorology
基金
中国气象局2025年复盘总结专项(FPZJ2025-124)
云南省气象局自筹科研项目(YZ202532、YZ202409)
云南省气象局基层台站气象科技创新与能力提升计划项目(STIAP202441)。
关键词
强降水
暖湿急流
不稳定条件
等熵位涡
severe precipitation
warm and moist jet,unstable condition,isentropic potential vorticity
