Development of Efficient Three-Dimensional Models of Lightning Discharges

高效三维闪电放电模型的开发

• 批准号: 0652148
• 负责人: Victor Pasko
• 金额: $ 46.25万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0652148&HistoricalAwards=false
• 关键词: Development; Efficient; Three; Dimensional; Models

A five-year effort will develop a set of efficient three-dimensional lightning models and apply these models to theoretically investigate a range of outstanding science questions related to thunderstorm electrification and development of different forms of lightning discharges. The outstanding questions which the research will seek to answer are:(1) Can lightning models based on a fractal approach provide realistic descriptions of different types of lightning discharges? What are the specific limitations of these models in terms of description of charges, potentials and electric fields of the overall lightning-thundercloud electric system? Can these models be modified to provide a computationally efficient parameterization of the streamer zones of both positive and negative lightning leaders? (2) What are the effective time scales of streamer-to-leader transition in air as a function of air pressure? What are the altitude range and other relevant physical conditions for which formation of leader channels is not possible in the Earth's atmosphere?(3) What are the specific thundercloud charge configurations which allow upward extensions of lightning leaders above thundercloud tops leading to recently discovered blue jet and gigantic jet phenomena? Are pressure scaled fractal models of streamer zones of positive and negative lightning leaders capable of describing experimentally observed features of blue jets and gigantic jets?The specific activities directed toward answering these questions will include development of three-dimensional numerical models based on a probabilistic approach to lightning modeling. These models will account for the best currently available knowledge for efficient representation of leader trees in the three dimensional computation domain and will include such features as open boundary conditions, preservation of full charge neutrality of leader trees at any point during simulations, and accurate modeling of lightning channels with finite resistivity. Model development will synergistically complement existing observationally-based research efforts at the New Mexico Institute of Mining and Technology directed toward investigation of electrical structure of thunderstorms, including studies of inverted-polarity electrical structures, lightning initiation studies, and studies of different and newly discovered types of lightning discharges.Broader impacts of the proposed activity include student training and education, synergistic collaboration between theoretical modelers and experimentalists, and the dissemination of results in the form of models to be shared with the community and in the form of publications summarizing new results.

为期五年的努力将开发一组有效的三维闪电模型，并将这些模型应用于理论上研究与雷暴电气化和开发不同形式的闪电放电有关的一系列杰出科学问题。 研究将寻求回答的杰出问题是：（1）基于分形方法的闪电模型可以对不同类型的闪电放电提供现实描述？ 这些模型的具体局限性是在整体闪电 - thundercloud电气系统的电荷，电势和电场的描述方面有什么？ 是否可以修改这些模型以提供正面和负闪电领导者的流媒体区域的计算有效参数化？ （2）空气中流媒体转变的有效时间尺度是什么？ 在地球大气中无法实现领导者通道的哪种高度范围和其他相关的物理条件？（3）哪些特定的ThunderCloud电荷配置是什么，可以使雷云顶部上方的闪电领导者向上扩展，从而导致最近发现的蓝色喷气喷气机和巨大的喷气现象？ 能够描述蓝色喷气机和巨大喷气机的正面和负闪电领导者的流板区域的压力缩放区域模型？用于回答这些问题的特定活动将包括基于灯光模型的概率方法的三维数字模型的开发。 这些模型将说明当前最佳的知识，以在三维计算域中有效地表示领导者树，并包括诸如开放边界条件，在模拟过程中的任何时候保存领导者的全充气中立性以及具有有限电阻率的闪电频道的准确建模。 模型开发将在新墨西哥州采矿与技术研究所协同补充，该研究旨在研究雷暴的电气结构，包括对倒置极性电气结构的研究，闪电启动研究，以及针对不同的和新发现的闪电的研究，包括学生培训和教育的实验者的影响，包括学生培训和教育的实验，包括学生的培训和教育的影响。以要与社区共享的模型的形式以及以总结新结果的出版物的形式传播结果。