四川盆地一次暴雨过程与重力波的关联特征  

Relationship Between a Heavy Rainfall and Gravity Wave in Sichuan Basin

作　　者：许一洲 李国平[1] 张晓玉 谢新 董元昌[3] Xu Yizhou;Li Guoping;Zhang Xiaoyu;Xie Xin;Dong Yuanchang(School of Atmospheric Science,Chengdu University of Information Technology,Chengdu 610225;Qingtian Meteorological Bureau of Lishui,Zhejiang,Lishui 323900;Institute of Plateau Meteorology,CMA,Chengdu 610218)

机构地区：[1]成都信息工程大学大气科学学院,成都610225 [2]浙江省丽水市青田县气象局,丽水323900 [3]中国气象局成都高原气象研究所,成都610218

出　　处：《应用气象学报》2025年第1期65-76,共12页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(42175002,42075013);四川省中央引导地方科技发展项目(2024ZYD0175)。

摘　　要：利用ERA5再分析资料、GPM卫星降水产品和WRF模式,对2023年7月2—3日四川盆地一次暴雨过程的重力波特征进行天气动力学分析和数值试验,以期加深对重力波影响暴雨机理方面的认识。结果表明:该过程降水呈波动特征,受急流、切变线和高空槽等系统影响。高层重力波在四川盆地南侧边坡由切变不稳定、非平衡流机制激发,并向东北传播;低层重力波由边坡地形强迫产生后向北传播,两列波动在夜间呈同位相耦合,期间降水区内不稳定能量释放明显增强。削去四川盆地南部不同范围山地的数值试验表明,降水最早出现于山地北部山脚向平原的过渡带。四川盆地南部地形通过对气流的下坡加速和辐射冷却差异产生的扰动位势高度梯度共同促使垂直风切变增强,从而影响重力波激发位置。四川盆地南侧山地阻碍西南通道的水汽输送,水汽辐合主要位于平原地区,导致降水大值出现在四川盆地中部,而非作为重力波激发地的南侧边坡和毗邻山地。Based on ERA5 reanalysis data,GPM precipitation data and WRF model,a synoptic dynamic analysis and numerical experiment are conducted to analyze gravity wave characteristics of a heavy rainfall in Sichuan Basin on 2 July and 3 July in 2023,in order to deepen the understanding of the mechanism of gravity wave affecting the basin rainstorm,and to discuss the cause of topography affecting the excitation of gravity wave and water vapor condition.Results indicate that precipitation exhibits fluctuating characteristics,influenced by several favorable factors,including water vapor flux convergence,strong vertical wind shear,and is affected by jet stream,shear line and upper trough.The upper gravity wave is initiated by shear instability and non-equilibrium flow mechanisms at the downslope of the southern Basin,propagating northeast.At night,the disturbance in geopotential height over the plateau extends into the upper troposphere,resulting in a stronger gradient of geopotential height between the plateau and the Basin.With the decrease in solar radiation heating,the influence will extend to 250 hPa,which will also impact the excitation of gravity waves.The low-level gravity wave is generated by the sloping topography and propagate northward,with two waves coupling in phase during the night.During this period,the release of unstable energy in the precipitation area is significantly enhanced.This phenomenon also suggests that in-phase wave coupling may be a contributing factor to the increase in precipitation at the energy level.Numerical experiments conducted on flattening various mountain ranges in the southern part of the Basin indicate that precipitation initially occurs in the transition zone between the northern foothills and the plain.The southern topography of the Basin enhances the vertical wind shear through the downhill acceleration and the disturbance geopotential height gradient caused by the radiative cooling difference,which affects the gravity wave excitation region and the precipitation region.Due to the

关 键 词：夜雨 四川盆地 重力波 地形作用 

分 类 号：P458.121.1[天文地球—大气科学及气象学]