Abstract

This paper continues the research started in [4] that investigates the thundercloud with hail observed over Saint Petersburg on July 22, 2017. The results of numerical simulation of the cumulonimbus cloud using a small-dimensional model are presented. The spatiotemporal variations in the updraft velocity, liquid water content, ice water content, volume charge density, electric field strength, and other parameters are studied. Two cases are simulated and intercompared: without and with the heterogeneous cloud droplet freezing. It is shown that the formation of precipitation including hail occurs more intensively in the second case. Special attention is paid to the simulation of cloud electric structure, which was performed in combination with the modeling of its dynamics and microstructure. It is demonstrated that the most powerful cloud electrification processes occur due to the interaction between cloud and precipitation particles (hailstone–ice crystal, melting hailstone–cloud droplet, raindrop–cloud droplet). The dynamics of the cloud electric structure at different life stages is modeled.

中文翻译：

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俄罗斯西北部积雨云演化和电结构的数值模拟

摘要

本文延续了[4]中开始的研究，该研究调查了2017年7月22日在圣彼得堡观测到的带雹的雷云。提出了使用小维模型对积雨云进行数值模拟的结果。研究了上升气流速度，液态水含量，冰水含量，体积电荷密度，电场强度以及其他参数的时空变化。模拟和比较了两种情况：没有和有异构云滴冻结的情况。结果表明，在第二种情况下，包括冰雹在内的降水形成更为强烈。结合云动力学和微观结构的建模，对云电结构的仿真给予了特别关注。事实证明，最强大的云层带电过程是由于云层与降水颗粒（冰雹–冰晶，冰雹–云滴，雨滴–云滴）之间的相互作用而发生的。对不同生命阶段的云电结构动力学进行了建模。