2015年8月19日铁岭局地飑线天气过程分析

Analysis of the Weather Process of Local Squall Line in Tieling on August 19,2015

在常规资料的基础上,利用FY-2E卫星云图、自动站、雷达回波等非常规资料,结合物理量场,对2015年8月19日铁岭局地飑线天气过程进行分析,探讨此次过程发生的可能原因和触发机制。结果表明,副热带高压稳定北抬,在高空冷涡控制下,加之前期持续高温,为此次中尺度飑线系统提供有力的环流背景;中尺度对流系统(MCS),在雷达强度回波中表象明显,为线性排列的对流单体族构成的窄带回波,回波强度>55 d BZ。垂直累计液态水含量VIL值≥40 kg/m2注意飑线天气,VIL值越大天气现象越强烈;温度总指数TT(TT≥50℃)、深对流指数DCI(DCI>26℃)也反映了热力不稳定和对流潜势,对临近和甚短期预报更具有指示意义。

Based on the conventional data,using the unconformity data of FY-2E satellite images,automatic station and radar echo,combined with the physical field,the weather process of the local squall line in Tieling was analyzed on August 19,2015,the possible causes and triggering mechanism of this process were discussed. The results showed that the subtropical high pressure was controlled by the high altitude cold vortex and the high temperature in the early period,which provided a powerful circulation background for the mesoscale squall line system. the performance of squall line mesoscale convective system（ MCS） in the radar intensity echo was obvious,it was a linear array of convective monomer family consisting of narrowband echo,its echo intensity was greater than 55 d BZ. The squall line weather was noted when vertical cumulative liquid water content（ VIL） ≥ 40 kg / m2; The temperature index TT（ TT≥50 ℃） and the deep convection index DCI（ DCI 26 ℃） also reflected the thermal instability and convective potential,and were more instructive for the near and very short term forecast.