中低层水平风速对闪电和降水影响的数值模拟

Numerical Simulation Study on the Effect of Middle-and Low-Level Horizontal Wind Speed on Lightning and Precipitation

利用三维雷暴云动力电耦合模式,对无风、弱风、中等强度风和较强风这四种不同中低层水平风速情况下雷暴的发展特征进行了敏感性试验。模拟结果表明,随着中低层水平风速增大,雷暴云内粒子生长受到抑制,云内起电过程将变得缓慢,起电区域发生转移,更长的起电时间使云内产生更大的电场、发生更剧烈的放电过程,但若风速过大,云内电场将被严重抑制而不发生放电,中等强度风最有利于闪电发生。中低层水平风速在一定范围内增长将使降水增多,但若风速过大,降水将减少。中低层水平风对闪电和降水影响明显,在对雷暴云闪电和降水的研究中应当综合考虑其对云内动力、微物理过程的影响。

In order to further understand the effect of the middle and low-level horizontal wind speed on the feature of thunderstorm dynamic field,electrical activities and precipitation,four sensitivity tests in a three-dimensional dynamics-electrification coupled model with different horizontal speeds,including without wind,weak wind,moderate intensity wind and somewhat strong wind were studied. The simulation results show that: As the wind speed increases,particle growth was inhibited,the electrification process of thunderstorm will be slowed down and the electrification regional transfer occurs,longer electrification time would make the storm produced more greater electric field and occurred more severe discharge process,however,if the wind is too strong,there would no lightning happen. Moderate intensity wind is most conducive to lightning. In addition,wind speed in a certain range of growth will increase the precipitation,but if the wind is too strong,precipitation will reduce.These results showed that middle and low-level speed can make significance impact on lightning and precipitation,we should comprehensive consider the wind speed influence on thunderstorm dynamic field and microphysical processes in the study of lightning and precipitation.