摘要
利用多源气象资料,对2022年6月17—22日广西极端暴雨过程低空急流与暴雨的关系进行精细化时空分析。结果表明:(1)该次极端暴雨是发生在中高低纬天气系统有利对峙的暖区降雨系统中,极端低空急流的脉动和高空槽的东移触发极端暴雨天气。(2)强降雨区主要位于925 hPa急流顶端以北、850 hPa急流核以北偏左侧的急流梯度最大区域附近,急流位置和强度与强降雨落区和强度相关。(3)低空急流建立强劲的水汽通道,强降雨对应水汽辐合中心。强降雨区位于△θse负中心南侧和东侧的等值线密集区域内,并沿着等值线密集区分布。低空急流为暴雨区上空的正涡度柱和低层辐合、高层辐散动力机制提供有利条件。(4)极端低空急流下,前倾槽过境,低层强烈辐合高层强烈辐散、深厚正涡度柱及水汽异常充沛是极端暴雨形成的重要原因。
Based on multi-source meteorological data,the effect of low-level jet on the extreme rainstorm in Guangxi during June 17-22,2022 was analyzed in a refined spatio-temporal perspective.The results show that:(1)The extreme heavy rainfall occurred in a warm-region rainfall system with favorable confrontation of high-to low-latitude weather systems.The pulsation of the extreme low-level jet stream and the eastward movement of upper-level trough triggered the occurrence of the extreme heavy rainfall weather.(2)The heavy rainfall area was mainly located near the largest jet gradient area north of the top of the 925hPa jet and left of the north of the 850hPa jet core.The position and intensity of the jet were related to the location and intensity of heavy rainfall.(3)The low-level jet has established a strong water vapor channel,and the heavy rainfall corresponded to the water vapor convergence center.The heavy rainfall area was located within and distributed along the dense area of contours on the south and east sides of the negative center of△θse.The low-level jet provided favorable conditions for the positive vorticity column and the dynamic cooperation mechanism of low-level convergence and high-level divergence over the rainstorm area.(4)Under the extreme low-level jet,the transit of the upper-level forward trough,the strong low-level convergence and strong upper-level divergence,the deep positive vorticity column,and the anomalous abundance of water vapor are important factors for the formation of this extreme rainstorm.
作者
黄芳
刘国忠
黄增俊
梁生
张丁丁
HUANG Fang;LIU Guozhong;HUANG Zengjun;LIANG Sheng;ZHANG Dingding(Guangxi Meteorological Observatory,Nanning 530022,China;Nanning Meteorological Bureau,Nanning 530029,China)
出处
《气象研究与应用》
2023年第3期1-8,共8页
Journal of Meteorological Research and Application
基金
中国气象局复盘总结专项项目(FPZJ2023-095)
广西分钟级对流尺度数值预报模式系统建设项目(桂气科2022ZL005)
广西极端暴雨形成机理及预报技术研究创新团队项目。
关键词
极端暴雨
低空急流
降雨特征
中小尺度分析
extreme heavy rainfall
low-level jet
rainfall characteristics
meso-micro scale analysis
