青藏高原东部地形对四川盆地东北部一次暴雨过程的影响
Effect of topography of eastern Qinghai-Xizang Plateau on a rainstorm occurred in northeastern Sichuan Basin
艾真珍 1董寅硕 2徐昕 3季玉枝 3衡志炜4
作者信息
- 1. 中尺度灾害性天气教育部重点实验室,南京大学大气科学学院,南京,210023;南京信息工程大学,南京,210044
- 2. 南京信息工程大学,南京,210044
- 3. 中尺度灾害性天气教育部重点实验室,南京大学大气科学学院,南京,210023
- 4. 中国气象局成都高原气象研究所,高原与盆地暴雨旱涝灾害四川省重点实验室,成都,610072
- 折叠
摘要
针对2021年8月8日发生在四川盆地东北部的一次暴雨,利用地面观测和再分析资料,结合WRF(Weather Research and Forecasting)敏感性数值试验,研究了青藏高原东部地形对本次暴雨过程的影响和机理.结果表明,暴雨发生期间四川盆地主要受500 hPa高压脊影响,青藏高原东南侧绕流形成的西南气流向暴雨区输送暖湿空气,并在盆地形成低涡.高低空系统的耦合使得气流辐合抬升,为暴雨发生提供了良好条件.当青藏高原东部地形高度降低以后,地形对气流的阻挡作用减弱,原先高原东南侧绕流产生的西南气流减弱变为偏西气流.同时,高原东北侧的西北气流加强并南下,进一步减弱四川盆地的南风分量和水汽输送,最终导致水汽在四川盆地东南侧聚集和暴雨落区的南移.
Abstract
In view of a rainstorm that occurred in the northeast of Sichuan Basin on 8 August 2021,this paper uses ground observation and reanalysis data,combined with WRF(Weather Research and Forecasting)sensitivity numerical experiments,to study the influence and mechanism of the eastern Qinghai-Xizang Plateau topography on this rainstorm process.The results show that during the rainstorm,the Sichuan Basin was mainly affected by the 500 hPa high ridge.The southwest airflow formed by the flow around the southeast side of the Qinghai-Xizang Plateau transported warm and humid air to the rainstorm area,and formed a vortex in the basin.The coupling of high and low altitude systems makes the air flow converge and rise,providing good conditions for rainstorm.When the terrain height in the eastern Qinghai-Xizang Plateau decreases,the blocking effect of the terrain on the airflow weakens,and the southwest airflow generated by the flow around the southeast side of the plateau weakens and becomes a westerly airflow.At the same time,the northwest air flow on the northeast side of the plateau strengthened and moved southward,further weakening the southerly wind component and water vapor transport in the Sichuan Basin,which eventually led to the accumulation of water vapor on the southeast side of the Sichuan Basin and the southward movement of the rainstorm area.
关键词
四川盆地/地形作用/强对流/数值模拟Key words
Sichuan Basin/topographic action/strong convection/numerical simulation引用本文复制引用
基金项目
国家重点研发计划(2023YFC3007502)
青藏高原综合科学考察研究项目(第二次)(2019QZKK0105)
出版年
2024
国家科技期刊平台
NSTL
万方数据