平凉一次雷暴云内的降水粒子分布及其电学特征的探讨

利用X波段多普勒双偏振雷达在甘肃平凉地区获取的一次雷暴过程资料,采用模糊逻辑判断法详细分析了该过程云内降水粒子的时空演变特征,同时结合该地区雷暴的电学特征,探讨了雷暴云电荷结构与云内降水粒子之间的关系。结果表明,在雷暴发展的不同阶段,各种降水粒子的数量存在较大的差异,霰粒子和干雪的演变特征与雷暴的发展、成熟到减弱过程对应比较一致。结合地面电场和雷达推断,冰相粒子特别是霰粒子和冰晶粒子与雷暴云的起电存在密切的关系。从各种粒子的垂直分布特征来看,中国内陆高原雷暴云下部正电荷区的强弱最有可能由霰粒子的多少来决定;同时利用霰粒-冰晶起电机制可以较好地解释雷暴云内三极性电荷结构的形成。

Distribution of Precipitation Particle and Electrical Characteristic of a Thunderstorm in Pingliang Region

The fuzzy logic hydrometeor classification(FHC) was applied to analyze the distribution of precipitation particles in a thunderstorm which was observed by a X-band dual polarimetric radar in Pingliang region,Gansu Province.Combining the electrical characteristics of thunderstorms in the study region,the relationship between charge structure and precipitation particles of thunderstorm are discussed in details.The results show that each type of precipitation particles take different magnituds at different stages of thunderstorm,and only the magnitudes of graupels and dry snow are consistent with the evolution of thunderstorm.According to the surface electrical field and radar results,it is concluded that the solid-state particles in particular graupels and ice are related to the charging of thunderstorm.The intensity of lower positive charge center of thunderstorm in the Chinese inland plateau is likely to determined by the quantity of graupels based on the vertical distribution of each type of precipitaiton particles.In addition,the graupel-ice charging mechanism can well be used to interpret the origin of the tripole charge structure of thunderstorm.