摘要
基于ERA5再分析资料和CMORPH卫星降水数据,对2019年9月9~10日发生在天山南脉的暴雨过程进行高分辨率数值模拟,分析位势不稳定变化特征;进一步开展地形敏感性试验,利用地形追随坐标系位势稳定度倾向方程研究不同尺度地形扰动对位势不稳定变化的影响。分析结果表明:(1)暴雨发生前低层大气位势不稳定显著,而随着暴雨发生发展,不稳定能量被释放,低层大气趋于位势稳定。(2)位势散度项是位势稳定度倾向方程的重要强迫项,主要由爬流引起。经向爬流垂直切变与广义位温经向梯度的耦合项是爬流位势散度的主导项。本次暴雨发生过程中,地形扰动通过改变经向爬流的垂直切变和广义位温的经向梯度,造成位势不稳定的发展。这些结果有助于提高新疆地区的暴雨预报水平。
The rainstorm that occurred during September 9–10 along the southern slope of the Tianshan Mountains was numerically simulated using the weather research forecast model.The European Meteorological Center ERA50.25°×0.25°reanalysis data and precipitation data from the CMORPH satellite were used for this simulation.The potential instability features were analyzed,and the influence of different scales of topography perturbations on the variation of potential instability was examined using a topographic sensitivity test and terrain-following tendency equation of potential stability.The study yielded the following results:(1)Before rainfall,the lower atmosphere exhibited potential instability.However,following the release of unstable energy,the lower atmosphere tended toward stability.(2)The potential divergence term,which was primarily caused by flow-over wind,was the main forcing term in the tendency equation of potential stability.The dominant factor in the flow-over potential divergence was the vertical shear of meridional flow-over wind combined with the meridional gradient of the generalized potential temperature.During the rainstorms,the development of potential instability was influenced by changes in the vertical shear of the meridional flowover wind and the meridional gradient of the generalized potential temperature due to topography perturbations.These changes contributed to the onset of the rainstorm.The insights gained from this study can help enhance the rainstorm forecast accuracy in Xinjiang.
作者
谢越
冉令坤
沈新勇
黄伟
周括
XIE Yue;RAN Lingkun;SHEN Xinyong;HUANG Wei;ZHOU Kuo(Key Laboratory of Meteorological Disaster,Ministry Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044;Laboratory of Cloud–Precipitation Physics and Severe Storms,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;Daishan Meteorological Bureau,Daishan 316200)
出处
《大气科学》
CSCD
北大核心
2024年第5期1817-1836,共20页
Chinese Journal of Atmospheric Sciences
基金
中国科学院战略性先导科技专项XDA17010105
新疆维吾尔自治区引进高层次人才天池计划项目(2019)
国家自然科学基金项目41930967。
关键词
暴雨
位势不稳定
地形敏感性试验
位势稳定度倾向方程
Rainstorm
Potential instability
Topographic sensitivity test
Tendency equation of potential stability
