Numerical Modeling Studies of Storm Electrification and Lightning

风暴带电和闪电的数值模拟研究

• 批准号: 0451639
• 负责人: Edward Mansell
• 金额: $ 55.7万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-15 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0451639&HistoricalAwards=false
• 关键词: Numerical; Modeling; Studies; Storm; Electrification

This project investigates the electrification and lightning production in mesoscale convective systems (MCSs), using a sophisticated three-dimensional numerical model with advanced microphysical, electrical and lightning parameterizations. The primary motivation for this numerical study is to gain physical understanding of the processes affecting electrification and lighting production from field observations of electrical storms by testing hypotheses derived from those observations. The principal investigators utilize improvements made to the model to study the time evolution of the horizontal/vertical charge structure of MCSs, those factors contributing to, and the lighting resulting from that structure. The ability to simulate the full life cycle of systems generates more robust correlations between lighting and storm properties. Specifically, they are comparing the relative contributions of local (stratiform region) charge separation processes versus advection of charge from the convective region, and testing the hypothesis that an inductive melting-fragmentation charge scheme is responsible for the near 273 K charge layers found in stratiform regions. Furthermore, they are studying the impact of the storm's evolution on its lighting production, focusing on the impact of merger or proximity of cells in the convective region, and ways in which the evolving charge structures in convective and stratiform regions interact to produce the often-observed cloud-to-ground lightning dipole (negative flashes near the convective region, positive from the stratiform region) and long horizontal flashes between the regions.The broader impacts of this work are its contribution to our understanding of the processes leading to storm electrification and lightning production, and high potential to resolve the current debate in the literature of the origins of charge in mesoscale convective systems. It aids in the interpretation of existing field observations, and will guide the design of future experiments. Two graduate students are funded under this work, and aspects of the research will find its way into a graduate course on atmospheric electricity at the University of Oklahoma, thus impacting many more students.

该项目研究了中尺度对流系统（MCS）的起电和闪电产生，使用先进的微物理，电气和闪电参数化的复杂三维数值模式。这项数值研究的主要动机是获得物理的理解，影响电气化和照明生产的过程中，通过测试来自这些观测的假设，从现场观测的电风暴。主要研究人员利用对模型的改进来研究MCS的水平/垂直电荷结构的时间演变、促成这些因素以及该结构产生的照明。模拟系统的整个生命周期的能力在照明和风暴属性之间产生了更强大的相关性。具体来说，他们正在比较当地（层状区域）电荷分离过程与对流区域电荷平流的相对贡献，并测试假设，即感应熔化-碎裂电荷方案负责层状区域中发现的近273 K电荷层。此外，他们正在研究风暴演变对其闪电产生的影响，重点是对流区单体合并或接近的影响，以及对流区和层状区不断演变的电荷结构相互作用产生经常观察到的云对地闪电偶极子的方式。（对流区附近的负闪，从层状区域呈阳性）这项工作的更广泛的影响是它对我们理解导致风暴电气化和闪电的过程的贡献生产，和高潜力，以解决目前的争论，在文献中的起源收费中尺度对流系统。它有助于解释现有的实地观察，并将指导未来实验的设计。这项工作资助了两名研究生，研究的各个方面将进入俄克拉荷马州大学的大气电研究生课程，从而影响更多的学生。