摘要:将云滴冻结方案植入已有的二维雷暴云起、放电模式，结合一次山地雷暴个例，探讨了气溶胶浓度对雷暴云微物理过程、起电以及空间电荷结构的影响。结果表明：气溶胶浓度增加，云滴数目增多，尺度降低，雨滴含量减少；云滴冻结导致冰晶在低温区快速生长，冰晶数浓度增加，尺度减小，当气溶胶浓度高于1000 cm-3后小冰晶难以增长成大尺度的霰粒子，因此霰粒子数浓度先增加后急剧减少。此外，气溶胶浓度的大小不会影响雷暴云的电荷结构特征，但会对云内的起电强度产生明显的作用：当气溶胶浓度较低时，增加气溶胶浓度，更多的冰晶和霰粒子发生碰撞使得云内起电过程增强，空间电荷密度增加；当气溶胶浓度高于1000 cm-3后，少量的霰粒子和小冰晶的出现抑制了非感应起电过程，导致电荷密度降低。
关键词:气溶胶/
云滴冻结/
非感应起电/
电荷结构
Abstract:A two-dimensional (2-D) cumulus model with electrification and lightning processes is implemented to investigate aerosol effects on microphysical process, electrification, and charge structure in thunderstorms. The 2-D cumulus model coupled with a droplet freezing module is used to simulate a SEET (Studies of Electrical Evolution in Thunderstorms) case. The results show that the number concentration of cloud droplets increases and its scale decreases with increasing aerosol concentration, but the content of raindrops reduces. Ice crystals grow rapidly in low temperature region, which is attributed to droplets freezing, and the number concentration of ice crystals increases but the scale decreases. The number concentration of graupels increases first and then decreases sharply because ice crystals are difficult to grow into graupels with larger scale when the aerosol concentration exceeds 1000 cm-3. In addition, the charge structure of thunderstorms is not affected by aerosol concentration, but aerosols have significant effect on the strength of electrification, i.e., when the aerosol concentration is lower, more ice crystals and graupels collision enhances the non-inductive charging process and increases the charge density as the aerosol concentration increases; however, the non-inductive charging rate starts to decrease when the aerosol concentration exceeds 1000 cm-3 due to the appearance of small ice crystals and little graupels, and the charge density is reduced.
Key words:Aerosol/
Cloud droplet freezing/
Non-inductive charging/
Charge structure
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