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东北冷涡引发的强雷暴个例分析

Investigation of severe thunderstorms caused by northeast cold vortex

  • 摘要: 2013 年6 月3 日辽宁省境内出现剧烈的雷电活动,在17 h 内观测到落雷14 103 次。使用静止卫星和多普勒雷达探测数据显示雷暴系统的发展特征,计算了该过程中辽宁省境内单位面积落雷密度,并对雷暴的生成环境和WRF-3.5.1模拟的雷暴云中冰晶、霰和雨滴等粒子数浓度的空间分布状态进行了探讨。结果表明:低空急流为雷暴过程的发展输送暖湿空气,形成强烈的对流运动;高空急流右侧和右前侧的下沉干冷空气进入0~-20 ℃雷暴云起电层区域,东北冷涡高低空急流形成的强垂直风切变造成雷暴云体上下出现较大角度的倾斜,高频次负地闪的发生与雷暴云体倾斜造成的特定电场结构有关;负主电荷积累区域和落雷区出现在上升气流较弱的带负电粒子沉降区域。

     

    Abstract: On 3 June 2013, an intense lightning event occurred in Liaoning Province. Within 17 hours, 14103 lightning strikes were observed.The lightning density is calculated in this study. The environment of the thunderstorms is analyzed, which shows that there is a convergenceand rising motion of warm air in the low level atmosphere. The sinking region appears in the height of 0~-20°C electrification layer tothe right or front right side of upper jet stream of the northeast cold vortex. The strong convective systems are studied based on the data of thegeostationary satellite and Doppler weather radar. The thunderstorm is simulated by WRF-3.5.1 model with Morrison microphysics scheme.The spatial distribution of number concentrations of raindrops, graupel particles and ice crystals is analyzed in association with the intenselightning. The body of thunderstorm clouds slopes down and the corresponding lightning flashes increase. The negative chargeaccumulationand lightning strike area appeared in the region where the updraft airflow was weak and the particles with negative charge fell.

     

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