冰晶繁生对雷暴云非感应起电影响的数值模拟

为了研究冰晶繁生在雷暴云发展过程中对非感应起电过程的影响,利用三维雷暴云模式在理想层结环境下,对雷暴云内各种水成物粒子、电荷以及电场分布情况进行数值模拟。模拟结果表明:在雷暴云发展和成熟阶段,有繁生过程参与的雷暴云中下部存在一个冰晶聚集区域,从而使得云内冰晶的数量较无繁生过程增大约1 5%～18%,且聚集的区域范围更大;同时,繁生过程的加入也使得霰粒子数量也比无繁生过程时增大约20%;霰冰非感应电荷转移的正区一般位于霰粒子浓度高值区附近,而负区位于冰晶和霰粒子浓度高值区相重合的区域;冰晶繁生过程通过影响雷暴云中冰晶和霰粒子浓度和分布位置,使得雷暴云非感应起电的强度和位置发生改变,导致云内起电过程提前约5～6 min。

Numerical Simulation of the Influence of Ice Crystal Multiplication on Non Inductive Electrification in Thunderstorm

In order to study the influence of ice crystal multiplication on non inductive electrification during the development of thunderstorm, a three dimensional numerical model of thunderstorm was used to evaluate the distribution of the variant particles, charge and the electric field in the thunderstorm with an ideal environment. The result shows that there is an ice crystal gathering area in the lower part of the thunderstorm with ice crystal multiplication during its development and mature stage. It makes the number of ice crystals in the case of multiplication increase by 15%-18% and the gathering area become larger compared to the condition without multiplication. And multiplication also makes the number of graupel particles in the condition with multiplication increase about 20%. The positive charged region always occurs nearby the area with high graupel concentration, while the negative charged region always appears in the overlap region with the high ice and graupel concentrations. Multiplication firstly influences the ice and graupel concentration and spacial distribution, then makes the non inductive electrification in thunderstorm more powerful and location change, and even the electrification process in single cell storm starts ahead 5-6 min.