王易,郑媛媛,庄潇然,张静,慕瑞琪,孙康远. 2022. 江苏典型下击暴流风暴结构特征统计分析[J]. 气象学报, (0):-, doi:10.11676/qxxb2022.023
江苏典型下击暴流风暴结构特征统计分析
Statistical Analysis of the Structural Characteristics of Typical Downbursts in Jiangsu Province
投稿时间:2021-08-21  修订日期:2022-01-28
DOI:10.11676/qxxb2022.023
中文关键词:  下击暴流,假相当位温,风切变,中层径向辐合,下沉气流
英文关键词:Downburst, Pseudo equivalent temperature, Wind shear,Mid-altitude radial convergence, Downdraft
基金项目:国家重点研发计划项目(2018YFC1507503),北极阁基金项目(BJG201907),江苏省气象局科研重点项目(KZ202001),江苏省“333工程”科研项目(BRA2020427),南京气象科技创新研究院北极阁开放研究基金(BJG202103),国家自然科学基金(U2142203),中国气象科学研究院基本科研业务费专项资金项目(2021Z003)
作者单位邮编
王易 江苏省气象台 210019
郑媛媛 南京气象科技创新研究院 210019
庄潇然 江苏省气象台 210018
张静 江苏省气象台 210019
慕瑞琪 江苏省气象台 210019
孙康远 南京气象科技创新研究院 210019
摘要点击次数: 137
全文下载次数: 97
中文摘要:
      [目的]为了研究江苏地区下击暴流的结构特征,[资料方法] 利用常规天气资料、雷达资料、自动站资料和ERA5再分析资料等,[结果]选取2007-2018年江苏地区19个典型下击暴流进行统计分析,[结论]结果表明:江苏下击暴流的分布呈现北多南少的趋势,以湿下击暴流为主,7月份是下击暴流的高发月份,孤立风暴型下击暴流具有弱的天气尺度强迫和上干下湿的结构,风暴移速较慢,飑线镶嵌型下击暴流具有很强的天气尺度强迫特征,风暴移速较快。下击暴流的初生阶段,强反射率因子核心和中层径向辐合出现在下击暴流发生前20-30分钟,而成熟阶段,强反射率因子核心高度有明显的降低,低层呈现明显的辐散结构。下击暴流影响期间地面温度有剧烈的变化,温度的降低伴随有明显的风速增大的过程。通过统计,产生下击暴流风暴的环境温度平均垂直递减率在6.8℃/km,能够保证负浮力的维持,干冷空气被中层辐合气流夹卷进入风暴内进一步加强了下沉气流,使得下击暴流得以维持和加强。
英文摘要:
      In this study, by using the conventional observation data, the radar data , the automatic meteorological station (AMS) data and ERA5 reanalysis product,19 typical downburst events in Jiangsu Province from 2007 to 2018 are statistically analyzed to reveal their structural characteristics. The results show high frequencies of downburst in the north of Jiangsu and low frequencies in the south, with wet downbursts dominating and high incidence in July. The downburst caused by an isolated storm is featured by weak synoptic-scale forcing, the structure of low-level wet and mid-high-level dry, and slow storm movement. However, the downburst in the squall line is featured by strong synoptic-scale forcing and fast storm movement. In the initial stage, strong reflectivity factors and mid-altitude radial convergences appear 20–30 minutes before the downburst. In the mature stage, the height of the strong reflectivity core is significantly descended, and the lower layer presents a divergence structure. The ground temperature changed drastically during the downburst, and the temperature drop is accompanied by a significant increase in wind speed. By statistics,the average vertical lapse rates of the temperature is 6.8℃/km, which can ensure the maintenance of negative buoyancy. The dry and cold air is entrained by the mid-level convergent airflow into the storm to further strengthen the downdraft, so the downburst can be maintained and strengthened.
查看全文   查看/发表评论  下载PDF阅读器
分享按钮