###
气象:2021,47(9):1073-1085
本文二维码信息
码上扫一扫!
重庆一次弱天气系统强迫下的极端短时强降水事件分析
李琴,邓承之
(重庆市气象台,重庆 401147)
Analysis of a Short-Time Extreme Precipitation Event in Chongqing Under Weak Synoptic Forcing
LI Qin,DENG Chengzhi
(Chongqing Meteorological Observatory, Chongqing 401147)
摘要
图/表
参考文献
相似文献
本文已被:浏览 17次   下载 877
投稿时间:2020-04-15    修订日期:2021-06-21
中文摘要: 利用常规观测、多普勒雷达、FY-2F卫星、加密自动站等数据和ERA-Interim 0.125°× 0.125°再分析资料,对2019年4月19日重庆极端短时强降水事件的环境条件和发展机制进行了分析。结果表明:在天气尺度垂直运动较弱的背景下,此事件由准静止的β中尺度对流系统(MβCS)形成。对流发展前本地水汽充足,“上干下湿”的层结不稳定特征显著。对流发生发展于云贵高原向四川盆地过渡的綦江河谷附近,河谷三面环山,地势由西南向东北倾斜。γ中尺度对流从河谷南侧下山增强,导致河谷内的局地强降水和冷池。冷池与河谷东坡上暖湿气团间的强中尺度水平温度梯度,有利于近地面西南风加速向东侧山体辐合,促使已移至河谷内的γ中尺度对流向东坡移动并加强为一个孤立的MβCS。受冷池的持续增强、东侧地形的阻挡、两个γ中尺度对流的并入和弱环境气流引导的共同影响,MβCS得以较长时间维持并影响同一局地区域,导致綦江、万盛局地发生极端短时强降水。
Abstract:Based on conventional weather data, FY-2F satellite data, Doppler radar products, densely-observed data from automatic surface weather observation system and ERA-Interim 0.125°×0.125° reanalysis data, the ambient condition and evolution of the short-time extreme precipitation event in Chongqing on 19 April 2019 is analyzed. The results show that under weak synoptic-scale vertical motion, this severe rain process was formed by a quasi-stationary meso-β scale convective system (MβCS) over Qijiang River Valley and its vicinity. Before the development of the severe convection, the local water vapor was sufficient, and stratification instability which was established and maintained by the wetter low-level and the drier mid-high-level was prominent. With the terrain inclining from southwest to northeast, Qijiang River Valley, located in the transition zone from Yungui Plateau to Sichuan Basin, was surrounded by mountains on three sides. Flowing from the south side of the valley, the increasing meso-γ scale convective cell brought about heavy rainfall and cold pool in the river valley. The strong mesoscale temperature gradient between the cold pool and the eastern slope of the valley promoted the intense convergence of the near-surface southwest wind to the eastern hillside, which was advantageous to the eastward convergence of the convective cell and strengthening, then the convection was organized into an isolated MβCS. With the coaction of continuous enhancement of the cold pool, topography blocking effect, merging of two MγCSs and weak ambient flow, the MβCS moved slowly, finally resulting in the localized extreme short-time rainfall over Qijiang and Wansheng.
文章编号:     中图分类号:    文献标志码:
基金项目:中国气象局预报员专项(CMAYBY2019-095)资助
引用文本:
李琴,邓承之,2021.重庆一次弱天气系统强迫下的极端短时强降水事件分析[J].气象,47(9):1073-1085.
LI Qin,DENG Chengzhi,2021.Analysis of a Short-Time Extreme Precipitation Event in Chongqing Under Weak Synoptic Forcing[J].Meteor Mon,47(9):1073-1085.