首页|一次天山南脉暴雨过程的位势稳定度变化特征及地形敏感性研究

一次天山南脉暴雨过程的位势稳定度变化特征及地形敏感性研究

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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.
Potential Stability Features and Topographic Sensitivity Simulation for a Rainstorm Process over the Southern Slope of the Tianshan Mountains,China
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 ERA5 0.25°×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 flow-over 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.

RainstormPotential instabilityTopographic sensitivity testTendency equation of potential stability

谢越、冉令坤、沈新勇、黄伟、周括

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南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心,南京 210044

中国科学院大气物理研究所云降水物理与强风暴实验室,北京 100029

岱山县气象局,岱山 316200

暴雨 位势不稳定 地形敏感性试验 位势稳定度倾向方程

中国科学院战略性先导科技专项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Flexible Talents Introducing Project of Xinjiang(2019)National Natural Science Foundation of China

XDA17010105XDA1701010541930967

2024

10.3878/j.issn.1006-9895.2211.22220

大气科学
中国科学院大气物理研究所

大气科学

CSTPCD北大核心
影响因子：2.11
ISSN：1006-9895
年,卷(期)：2024.48(5)