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.

雷暴是一种高带电现象，闪电是由云内电荷分离形成的，雷暴不仅会产生云对地和云对云的闪电，而且雷暴还会产生向上的放电。这些被称为云顶放电，根据其大小和外观有许多不同的名称，例如精灵、精灵和喷流。虽然这些放电已被拍摄到，但科学的记录却很少。这些事件的研究质量数据尚未得到解答，该奖项将涉及两种新仪器的开发和多年的观测工作，以提供有关云顶放电的最全面的数据。该项目向社会提出的一点是，向上的放电会产生大量的氮氧化物，这会影响平流层的臭氧化学。该奖项还包括向佐治亚州的农村学校提供有关电和磁主题的科学教育。研究云顶的电学性质放电（CTD），如精灵、侏儒、小精灵、启动器、喷射流和巨大喷射流，以及雷暴如何产生这些独特的事件，由于先前的观测限制，研究团队将开发和部署一个。新型地面光谱成像系统由两个蓝光敏感高速摄像机组成，蓝色方面很重要，因为 CTD 的特点是主要是蓝色，但也有蓝色和紫外 (UV) 光。被低层大气严重散射，并且大多数先前的光学成像仪对蓝色/紫外线不敏感。新系统将部署在德克萨斯州，并结合来自甚低频（VLF）/低频（LF）无线电接收器的额外观测信息。 、闪电测绘阵列 (LMA) 和传统气象数据，以回答有关 CTD 的电学和形态特性以及 CTD 雷暴电荷结构表征的关键问题，具体研究问题包括： • 什么是先导和流光动力学。 CTD 的变化，例如先导的热温度和流束的电子能量的演变？• 先导到流束过渡区域的定量特征是什么？• 如何测量云上方产生的 LMA 的甚高频 (VHF)？ • 哪些参数决定 CTD 的终端高度？• 母风暴电荷结构是什么？形成它们的气象过程是什么？• 云顶混合和散度、雷暴电荷结构和事件形成之间的关系是什么？风暴结构因不同而不同CTD？该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。