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2025年4月11—13日我国大范围极端大风天气过程特征和成因

Characteristics and formation mechanisms of the widespread extreme gale weather process in China during April 11-13, 2025

  • 摘要: 2025年4月11—13日,我国北方和中东部发生一次大范围大风天气过程。利用常规观测、风廓线雷达观测、再分析等资料分析了此次过程极端大风的观测特征、天气尺度和中小尺度成因以及极端性成因。结果表明:此次过程具有分布范围广、持续时间长、强度大、极端性强、极大风速不断加强、伴有多种灾害性天气等特征;64个国家级气象观测站阵风风速突破历史极值,其中最大的极大风速达46.8 m·s−1。产生此次过程的主要天气系统是南下的大范围地面反气旋、高空冷涡和斜压扰动形成的地面气旋,此次过程是一次典型的大范围强冷空气爆发和斜压扰动发展过程。此次过程的关键形成机制是对流层中层的涡度平流和中低层的强温度平流。此次过程的极端性成因是极端强的大范围冷暖空气异常及其相互对峙形成了极端强的斜压性大气,从而产生了大范围强的位势高度梯度和高低空急流。黄土高原等大范围的高海拔地形产生的热力作用阻滞冷空气前沿大风区的推进,但背风波等产生中尺度下沉运动通过动量下传产生局地强阵风。显著的垂直风切变形成了活跃的湍流活动,导致强垂直混合作用;中尺度波动会产生较强的下沉运动。这些因素共同作用使得高空大风动量下传到地面,形成局地极端强阵风。

     

    Abstract: A widespread gale process occurred across northern and central-eastern China from April 11 to 13, 2025. Based on conventional observations, wind profiler data, and reanalysis data, this study presents the observational characteristics, synoptic-scale and mesoscale mechanisms, and contributing factors to the extremity of wind gales. The results are as follows. This process was characterized by extensive coverage, prolonged duration, exceptional intensity, record-breaking extremity, progressively intensifying wind gusts, and concurrent multiple types of hazardous weather phenomena. Sixty-four national-level meteorological stations recorded historic maximum gust speeds, with the maximum reaching 46.8 m·s−1. The primary synoptic systems responsible for this process were a large-scale southward-moving surface anticyclone, an upper-level cold vortex, and surface cyclones generated by baroclinic disturbances, constituting a typical case of extensive cold-air outbreak coupled with baroclinic disturbance development. The synoptic-scale formation mechanism involved mid-tropospheric vorticity advection and lower-to-middle tropospheric strong thermal advection. The extremity of this process was attributed to exceptionally intense large-scale anomalies of cold and warm air masses and their frontal confrontation, which generated extreme baroclinicity that subsequently established extensive, steep geopotential height gradients and vertically coupled jets. The thermodynamic effects induced by extensive high-altitude regions, particularly the Loess Plateau, acted to impede the advancement of the gale zone along the cold air front. However, the mesoscale downdraft of lee waves generated localized high wind gusts through downward momentum transport. Strong vertical wind shear triggered vigorous turbulent motions, inducing strong vertical mixing. Simultaneously, mesoscale waves produced intense downward motion. These combined dynamical processes facilitated the downward transport of upper-level momentum to the surface, generating localized extreme wind gusts.

     

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