非感应起电参数化方案的对比性研究

A Comparative Study of Prelightning Thunderstorm Electrification with Different Noninductive Charging Mechanisms

为进一步研究不同的非感应起电机制对模拟云内电场的可适用性,把3种不同的非感应起电参数化方案引入三维强风暴动力和电耦合数值模式,以2005年6月10日发生在长春的一次雹暴过程为例,模拟分析第一次闪电发生前云内电场的发展情况。结果表明,电荷的产生始于过冷水含量中心,并随着过冷水含量中心的向上发展而上移;在-20～-30℃层存在一电荷的累积区,雷达回波跃增出现后的10min左右,电场迅速增长,且在4～8min内由不足50kV.m-1增长到110kV.m-1以上。采用方案一形成的主电荷区为偶极性结构,而采用方案二和方案三形成的为比较常见的三极性结构。对比其他地区的观测资料及模拟结果,表明相同的云体宏微观条件下,不同方案中极性反转温度的不同对云内中低层电荷的分布存在较大的影响。考虑低层正电荷区的发展及冰相粒子与过冷水含量的配置关系,取极性反转温度为-10～-20℃,方案二的模拟结果与实际较一致。

To provide further insight into the applicability of noninductive charging mechanisms to the modeling of intracloud electrification,three different parameterizations of noninductive charging were introduced into the 3D dynamics-electrification coupled model,and electrical evolution before the first lightning was simulated with hailstorm happened on 10 June 2005 in Changchun.The numerical results show that the main charging process moves upward with the development of cloud,and charges accumulated at the-20 ...