雷暴电过程对动力发展的影响研究

Study on Influence of Electrical Processes on Dynamical Development in Thunderstorm

利用三维时变积云动力—电过程耦合模式对雷暴中的电过程对动力发展的影响进行了模拟计算。结果表明,随着雷暴云体发展,云内形成三极性电荷结构。电场力对雷暴发展的直接作用与动力场相比很小,电涡度10-6·s-1比动力涡度小两个量级。但电场力影响了雷暴中的微物理过程,特别是水成物粒子的降落速度,并通过对三相水成物之间转换过程的调制,改变了三相水成物的时空结构,使云中水汽总量增加41%,释放潜热增加19.4%,从而改变了流场结构,电涡度达到10-4·s-1量级,和动力涡度相当。模拟结果指出,雷暴内电过程在云体成熟阶段对雷暴发展有较大影响。

The influence of electrical processes on dynamical development was calculated by using a three-dimensional dynamics and electrification coupled model. The results revealed that the triple electrical structure was formated with the development of simulated thunderstorm. The direct effect of electric field force on development of thunderstorm was smaller than that of dynamics. The vorticity that electric field force produced was 10^(-6)·s^(-1) and 2 orders smaller than that of dynamics. However, the electric field force influenced the microphysical processes, especially the falling velocity of hydrometeors. The electrical processes changed the temporal and special structures of hydrometeors distribution by adjusting the transformation between hydrometeors. By this way, the water vapor increased by 41% and the latent heating increased by 19.4%. The structure of stream field was changed and electrical vorticity was about 10^(-4)·s^(-1). It corresponded to that of dynamics. Therefore, there was a large influence of electrical processes on development of thunderstorm in mature stage of thunderstorm.