“2012.8.13”玉溪强对流天气成因分析

Analysis of the Rare Strong Convection Weather Process on Aug. 13th 2012 in Yuxi

利用micaps资料、区域自动雨量站、多普勒雷达回波资料,对2012年8月13日发生在滇中玉溪的强对流天气过程进行诊断分析。结果表明,此次强对流过程历时短、雨强大、受灾重、突发性强,是由台风低压倒槽西移和地面辐合线等中小尺度系统扰动诱发的;地面到中低层小温度露点差、低层偏南暖湿气流辐合和强潜在不稳定能量、位势不稳定为强对流过程提供了所需的水汽和能量条件;过程中有位势不稳定能量释放和中尺度雷暴高压活动,强对流发生地上空近地层强水汽辐合和垂直上升运动维持时间短。雷暴高压对应有其影响地近地层有水汽辐散和逆风区回波;灾害性大风、冰雹发生在最强回波、最高回波顶和垂直累积液态水含量呈跃增之后,短历时强降水则发生在最大垂直累积液态水含量维持时。

Based on the data of micaps,regional automatic rainfall station and Dopplor radar,causes of the rare strong convection weather process happened in Yuxi on Aug.13th,2012 were analyzed.The results showed that it was short duration,heavy rainfall intensity,severely disaster and unexpected process.It was aroused by meso-and micro-scale systems such as tropical depression trough and surface convergence line.Vapor and energy condition in strong convection weather process were satisfied because of small depression of the dew point from surface to mid-low level,warm and wet flow convergence on low layer and strong potential instability energy.There were release of potential instability energy and activity of meso-scale thunderstorm.Endurance period of water vapor convergence and vertical velocity were short at strong convection weather place on surface layer.There were vapor divergence and AWR echo area on surface layer at area which was impacted by thunderstorm.The wicked storm,hailstone happened after strongest echo,highest vertically integrated liquid and VIL increased in a leap.Short time strong rainfall happened during the maintenance period of biggest VIL.