Collaborative Research: Cloud Top Discharges and their Parent Storms

合作研究：云顶放电及其母风暴

• 批准号: 2330350
• 负责人: Levi Boggs
• 金额: $ 119.06万
• 依托单位: Georgia Tech Applied Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2027-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2330350&HistoricalAwards=false
• 关键词: Collaborative; Research; Cloud; Top; Discharges

Thunderstorms are highly-electrified phenomena where lightning is formed from the separation of electrical charge within the cloud. Not only do thunderstorms produce cloud-to-ground and cloud-to-cloud lightning, but thunderstorms also can produce upward-pointed electrical discharges from the tops of the clouds. These are known as cloud top discharges and have many different names based on their size and appearance, such as sprites, pixies, and jets. While these discharges have been photographed, there are very few scientific research-quality data available for these events, and a variety of questions remain unanswered. This award will involve the development of two new instruments and a multi-year observational effort to provide the most comprehensive data on cloud top discharges available. The relevance of this project to society is that upward electrical discharges are strong producers of NOx which can affect stratospheric ozone chemistry. This award also includes outreach to rural schools in Georgia to provide science education on the topics of electricity and magnetism. The overall objective of this project is to investigate the electrical nature of cloud top discharges (CTDs) such as sprites, gnomes, pixies, starters, jets and gigantic jets and how thunderstorms produce these unique events. Observations of these CTDs are rare due to prior observational constraints. In this project, the research team will develop and deploy a new ground-based spectroscopic imaging system consisting of two blue-sensitive high-speed cameras. The blue aspect is important because CTDs are characterized by their predominantly blue color, but blue and ultraviolet (UV) light is heavily scattered by the lower atmosphere and most prior optical imagers were not sensitive to blue/UV light. The new system will be deployed in Texas and combined with additional observational information from Very Low Frequency (VLF)/Low Frequency (LF) radio receivers, Lightning Mapping Arrays (LMAs), and traditional meteorological data to answer key questions about the electrical and morphological properties of CTDs and the characterization of CTD thunderstorm charge structures. Specific research questions include:• What are the leader and streamer dynamics of CTDs, such as evolution of thermal temperature for leaders and electron energy for streamers?• What are quantitative characteristics of the leader-to-streamer transition region? • How is the very high frequency (VHF) measured by LMAs produced above the cloud? • What parameters dictate the terminal altitude of a CTD?• What are the parent storm charge structures and what meteorological processes form them?• What is the relationship between cloud top mixing and divergence, the thunderstorm charge structure, and event formation?• How does the storm structure vary for different CTDs?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

雷暴是一种高度带电的现象，闪电是由云层中的电荷分离形成的。 雷暴不仅会产生云对地和云对云的闪电，而且雷暴还会从云层顶部产生向上指向的放电。 这些被称为云顶放电，并根据其大小和外观有许多不同的名称，如精灵，精灵和喷气机。 虽然这些排放已经被拍摄下来，但这些事件的科学研究质量数据很少，各种问题仍然没有答案。 该奖项将涉及两个新仪器的开发和多年的观测工作，以提供最全面的云顶排放数据。 该项目与社会的相关性在于，向上的放电是氮氧化物的强生产者，可以影响平流层臭氧化学。 该奖项还包括对格鲁吉亚农村学校的推广，以提供关于电和磁的科学教育。 该项目的总体目标是调查云顶放电（CTD）的电气性质，如精灵，侏儒，精灵，启动器，喷气机和巨大的喷气机，以及雷暴如何产生这些独特的事件。 由于先前的观察限制，这些CTD的观察结果很少。 在该项目中，研究团队将开发和部署一种新的地面光谱成像系统，该系统由两台蓝敏高速相机组成。 蓝色方面是重要的，因为CTD的特征在于其主要是蓝色，但是蓝色和紫外（UV）光被低层大气严重散射，并且大多数现有的光学成像器对蓝色/UV光不敏感。 新系统将部署在德克萨斯州，并结合来自甚低频（VLF）/低频（LF）无线电接收器，闪电测绘阵列（LMAs）和传统气象数据的额外观测信息，以回答有关CTD电气和形态特性的关键问题以及CTD雷暴电荷结构的表征。 具体的研究问题包括：·CTD的先导和流光动力学是什么，例如先导的热温度和流光的电子能量的演变？先导-流光过渡区的定量特征是什么？·甚高频（VHF）是如何通过在云层上方产生的LMA测量的？·哪些参数决定CTD的终端高度？·什么是母风暴电荷结构和什么样的气象过程形成它们？·云顶混合和辐散、雷暴电荷结构和事件形成之间的关系是什么？·对于不同的CTD，风暴结构如何变化？该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。