| 覃皓,周云霞,农孟松,黄晴.一次桂北暴雨过程中低涡的发展维持机制[J].沙漠与绿洲气象,2024,18(2):68~75 |
| 一次桂北暴雨过程中低涡的发展维持机制 |
| Development and Maintenance Mechanisms of the Vortex during a Rainstorm Process in North Guangxi |
| 投稿时间：2023-03-07 修订日期：2023-04-06 |
| DOI： |
| 中文关键词: 低涡 涡度方程 非地转 潜热加热 |
| 英文关键词:vortex vorticity equation ageostrophic latent heating |
| 基金项目:广西气象科研计划项目（桂气科2021Z03），广西自然科学基金项目（2022GXNSFBA035565），广西壮族自治区气象局短时临近天气预报技术创新团队项目 |
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| 中文摘要: |
| 利用常规观测、卫星数据及ERA5再分析数据，从动力和热力角度对引发2020年5月24-25日广西北部暴雨过程的低涡发展维持机制进行了诊断分析。结果表明：低涡在滇黔桂交界一带生成，随后逐渐发展东移，对流云团及降水落区主要分布在低涡东侧及南侧。涡度方程诊断表明，低涡的发展维持主要受涡度平流项和水平散度项影响。水平风场对涡度的输送使得局地涡度减小，而水平风场的辐合效应使得局地涡度增大。将原始风场分解为地转风和非地转风分量后发现，非地转风分量主导了局地涡度的变化，非地转风水平散度项正贡献最大，扭转项次之，两者是造成低涡发展维持的主要原因。在热力作用方面，低涡发展移动过程中对流层中层附近的潜热加热正反馈也有利于低层低涡的发展维持。 |
| 英文摘要: |
| Based on the conventional observation, satellite data and ERA5 reanalysis data, the development and maintenance mechanism of the vortex that causing regional rainstorm in northern Guangxi during 24-25 May 2020 is analyzed from the dynamic and thermal perspectives. The results show that the vortex forms at the boundary of Yunnan, Guizhou and Guangxi, and then gradually develops and moves eastward. The convective clouds and precipitation areas are mainly distributed on the east and south sides of the vortex.The diagnosis of vorticity equation shows that the development and maintenance of vorticity are mainly affected by vorticity advection term and horizontal divergence term. The vorticity transported by horizontal wind field reduces local vorticity, while the convergence effect increases local vorticity. When the original wind field is decomposed into geostrophic and ageostrophic wind components, it is found that the ageostrophic wind components dominate the variation of local vorticity, and the horizontal divergence term of ageostrophic wind makes the largest positive contribution, followed by the torsional term, which are the main reasons for the development and maintenance of vorticity. In terms of thermal effect, the positive feedback of latent heating near the mid level troposphere during the development and movement of vortex is also conducive to the development and maintenance of vortex. |
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