山东一次飑线过程的闪电特征和大风形成机制分析

利用闪电定位资料、多普勒雷达资料和卫星资料分析2016年6月13日发生在山东的一次飑线天气过程的地闪变化特征和大风形成机制,结果表明:本次过程发生在东北冷涡影响背景下,大气层结上冷下暖,随着层结不稳定性逐渐增强和不稳定能量的积蓄,在较强的深厚垂直风切变环境下触发强对流风暴进而组织成飑线。整个飑线过程中负地闪占主导地位,约占地闪总数的89.25%;在飑线的成熟阶段,负地闪频数达到最大峰值后的5～10 min,正地闪也出现最大峰值;负地闪主要出现在回波发展至成熟阶段,多发生在45 dBZ的强回波区域中;正地闪主要出现在飑线的成熟至消散阶段;当TBB达到最低值时,飑线达到最强盛阶段,地闪频数达顶峰。利用WINDEX计算的地面最大风速的潜势与观测的地面极大风速较接近;地面大风阶段对应着剧烈的闪电活动,冰雹大风等灾害性天气的最强时刻与正地闪的峰值出现时间较为一致。

Analysis of lightning characteristics and formation mechanism of strong wind in a squall line in Shandong

By using lightning localization data, Doppler radar data and satellite data, the characteristics of ground flash and the formation of strong winds in a squall line weather process occurred in Shandong on 13 June 2016 were analyzed. Results show that: the process occurs under the influence of the Northeast cold vortex, the atmosphere is cold above and warm below, and with the gradual instability of the stratification and the accumulation of unstable energy, a strong convective storm is triggered in a deep vertical wind shear environment and then organized into a squall line. Negative ground flash dominates the entire squall line, accounting for 89.25% of the total number of ground flashes; at the maturity stage of the squall line, the maximum flash peak occurs at 5-10 minutes after the negative ground flash frequency reachs the maximum peak; the ground flash mainly occurs in the echo-to-mature phase, which occurs mostly in the strong echo region of >45 dBZ; the positive flash mainly occurs in the stages of mature to dissipated phase of the squall line; when the TBB reach the lowest value, the squall line reaches the strongest. At the peak stage, the frequency of the ground flash reach its peak. The potential of the maximum wind speed calculated by WINDEX is close to the observed maximum surface wind speed; the ground windy stage corresponds to the intense lightning activity, the strongest moment of the severe weather such as hailstorm and the peak time of the positive flash Consistently, this provides a certain reference value for monitoring and warning of severe weather.