摘要
2022年6月3-4日广西东北部遭遇一次暖区暴雨过程,过程雨势强、累计雨量大,造成洪涝并引发滑坡等次生灾害。为丰富对广西暖区暴雨机理的认识,为预报服务提供参考,利用多源资料结合动能方程和层结稳定度倾向方程,对此次过程的动、热力过程进行了诊断分析,得出以下结论:高层南亚高压东侧辐散、中层低槽及低层低涡的维持,为强降水提供了有利的环流背景。西南季风强盛暖湿输送,为暴雨发生发展提供充足水汽。准静止α中尺度对流系统及列车效应造成强降水在局地累积,落区主要位于TBB梯度大值区。925 hPa急流出口区与850 hPa急流左侧正涡度区相重合,以及地形作用,为强降水发展提供动力条件。低涡东南侧位势高度自南向北减小配合偏南风,导致局地动能增长,是夜间低空急流发展的主要原因。急流发展一方面增强低层辐合,促进上升运动发展;另一方面低空急流偏南风流场与等θ_(se)线配置形成局地锋生强迫,有利于暴雨的触发及加强维持。整个过程都伴随显著的低层对流不稳定:强降水发生前期,不稳定层结主要由水平平流项和位势散度项共同维持;最强降水阶段,强暖湿输送及上升运动使900700 hPa上对流不稳定持续发展,位势散度项促进925 hPa边界层附近不稳定维持。
Northeast Guangxi suffered a warm-sector rainstorm process during 34 June 2022,featured with intensive rainfall and large accumulated rainfall amount,causing flooding and landslide and other secondary disasters.To enrich the understanding of the mechanism of warm-sector rainstorm of Guangxi and provide reference for forecasting services,the dynamic and thermal processes of the warm-sector rainstorm are diagnosed and analyzed based on multi-source data as well as the kinetic energy equation and stratified stability tendency equation.The results show that the divergence in the east side of the South Asia high,the maintenance of mid-level trough and low-level vortex provided a favorable background for the torrential rainfall.The strong warm-humid southwest monsoon provided sufficient water vapor for the occurrence and development of the torrential rainfall.The quasi-stationary meso-α-scale convective system and train effect caused the local accumulation of heavy precipitation,which was mainly located in the large TBB gradient region.The positive vorticity zone on the left of 850 hPa jet coincided with the exit zone of 925 hPa jet and the mountain terrain barrier provided dynamic conditions for the development of the severe precipitation.The increase of local kinetic energy caused by the decrease of geopotential height from south to north along with southerly wind was the main cause for the development of low-level jet at night.On the one hand,the development of low-level jet enhanced the low-level convergence and promoted the development of ascending motion.On the other hand,the pattern of low-level jet with southerly flow and theθse isoline formed local frontogenesis forcing,conducive to triggering and strengthening the maintenance of torrential rain.The whole process was accompanied by significant low-level convective instability,and the unstable stratification in the early stage of precipitation was jointly maintained by horizontal advection term and potential divergence term.In the heaviest rainfall stage,the strong warm-humid air transport and the upward motion made the convective instability over 900700 hPa develop continuously,and the potential divergence term promoted the instability near the 925 hPa boundary layer.
作者
覃皓
邱滋
黄明华
朱丽云
Qin Hao;Qiu Zi;Huang Minghua;Zhu Liyun(Guangxi Meteorological Observatory,Nanning 530022,China;Open Laboratory of Guangxi Beibu Gulf National Climate Observatory,Nanning 530022,China;Guangxi Meteorological Disaster Prevention Technology Center,Nanning 530022,China)
出处
《气象与环境科学》
2025年第6期1-10,共10页
Meteorological and Environmental Sciences
基金
广西重点研发计划项目(桂科AB25069126,桂科AB25069132)
广西气象科研计划项目(桂气科2024Z02)。
关键词
暖区暴雨
低空急流
动能
锋生强迫
层结稳定度倾向
warm-sector rainstorm
low-level jet
kinetic energy
frontogenesis forcing
stratification stability tendency
