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夏艳羚, 谭涌波, 向春燕, 马肖, 张鑫. 放电后电荷重置对雷暴云电荷结构及闪电行为的影响[J]. 气候与环境研究, 2017, 22(4): 487-498. DOI: 10.3878/j.issn.1006-9585.2017.16213
引用本文: 夏艳羚, 谭涌波, 向春燕, 马肖, 张鑫. 放电后电荷重置对雷暴云电荷结构及闪电行为的影响[J]. 气候与环境研究, 2017, 22(4): 487-498. DOI: 10.3878/j.issn.1006-9585.2017.16213
Yanling XIA, Yongbo TAN, Chunyan XIANG, Xiao MA, Xin ZHANG. Effects of Charge Redistribution after Discharges on the Charge Structure of Thunderstorms and Lightning Characteristics[J]. Climatic and Environmental Research, 2017, 22(4): 487-498. DOI: 10.3878/j.issn.1006-9585.2017.16213
Citation: Yanling XIA, Yongbo TAN, Chunyan XIANG, Xiao MA, Xin ZHANG. Effects of Charge Redistribution after Discharges on the Charge Structure of Thunderstorms and Lightning Characteristics[J]. Climatic and Environmental Research, 2017, 22(4): 487-498. DOI: 10.3878/j.issn.1006-9585.2017.16213

放电后电荷重置对雷暴云电荷结构及闪电行为的影响

Effects of Charge Redistribution after Discharges on the Charge Structure of Thunderstorms and Lightning Characteristics

  • 摘要: 为探究放电后电荷重置对雷暴云电过程的影响,在已有的三维雷暴云起、放电模式中分别加入两种不同的电荷重置方案:一种是植入法即放电后闪电通道上的感应电荷与原空间电荷叠加(简称ZR方案);另一种是中和法即放电后直接按一定比例降低闪电通道处的空间电荷浓度(简称ZH方案)。利用长春一次探空个例进行敏感性试验,发现放电后重置方式的不同会导致闪电特征存在明显差异:1)ZR方案下的云闪发生率比ZH方案下的云闪发生率少。闪电放电后ZR方案在云中植入异极性电荷,对雷暴云中电荷的中和量比ZH方案多,摧毁云中电场的能力更强;2)ZR方案下的正、负地闪发生率均比ZH方案多。相对于ZH方案,ZR方案中主正电荷区的分布范围大于主负电荷区,导致其出现了更多的正地闪;ZR方案中的云顶屏蔽层与主正电荷区的混合程度高,混合时间长,导致ZR方案在主正电荷区与主负电荷区之间触发了更多的负地闪;3)ZR方案下的闪电通道长度比ZH方案下的闪电通道长度短。ZR方案在云中植入异极性电荷,导致云中难以形成大范围同极性电荷堆,闪电通道传播局限在一对较小的异极性电荷堆内,而ZH方案不改变云中电荷分布,存在大范围同极性电荷堆,闪电通道传播范围较大。

     

    Abstract: To investigate the effects of charge redistribution after discharges on lightning characteristics, a threedimensional (3-D) cumulus model with electrification and lightning process is coupled with two different schemes of charge redistribution. In one scheme, i.e. the ZR scheme for short, the induced charges are added to the space charges along the lightning channel; in the other scheme, called ZH scheme for short, the charge density along the lightning channel is reduced by a certain percentage. Sensitivity experiments are performed using the sounding data collected at Changchun. Obvious differences between the lightning characteristics are found using the above two different ways of charge redistribution. The results show that:1) The intra-cloud flash rate in the ZR scheme is less than that in the ZH scheme. Charges with opposite polarity are embedded in the charge region, and more charges are neutralized in the ZR scheme than in the ZH scheme, which causes the electric field in the ZR scheme to drop more sharply. 2) The positive and negative cloud-to-groundflash rates in ZR scheme both are higher than that in the ZH scheme. Compared with that in the ZH scheme, the distribution range of the positive charge region is larger than the lower negative charge region, leading to a higher positive cloud-to-ground flash rate in the ZR scheme than that in the ZH scheme. Meanwhile, the degree of mixing of the shielding charge region at the cloud top with the positive charge region is stronger and the time of mixing is longer in the ZR scheme, thereby more negative cloud-to-ground flashes initiated between the positive charge region and the lower negative charge region are triggered in the ZR scheme. 3) The lightning channel length in the ZR scheme is shorter than that in the ZH scheme. Charges with opposite polarity are embedded in the charge region, and it is difficult to form large charge regions with the same polarity. The transmission of the lightning channel is limited to a couple of small charge regions with opposite polarity in the ZR scheme. However, the distribution of the charge regions in the ZH scheme does not change and there are large charge regions with the same polarity, while the range of the transmission of the lightning channel is also larger.

     

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