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: 2330351
• 负责人: Timothy Logan
• 金额: $ 6.52万
• 依托单位: Texas A&M University
• 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=2330351&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.

雷暴是高度电动的现象，其中闪电是由云中电荷的分离形成的。雷暴不仅会产生云到地面和云到云的闪电，而且雷暴还可以从云层的顶部产生向上的电气放电。这些被称为云顶部放电，并根据其大小和外观（例如精灵，像素和喷气式）具有许多不同的名称。尽管这些排放奖获得了该奖项，将涉及开发两种新工具和多年观察工作，以提供有关可用云顶部排放的最全面数据。该项目与社会的相关性是向上的电气放电是NOX的强大生产者，可能会影响平流层臭氧化学。该奖项还包括向佐治亚州粗糙学校的宣传，以提供有关电力和磁性主题的科学教育。该项目的总体目的是研究云顶部放电（CTD）的电性质，例如精灵，侏儒，小精灵，起动器，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。由于先前的观察约束，对这些CTD的观察很少见。在该项目中，研究团队将开发和部署新的基于地面的蓝色方面很重要，因为CTD的特征是它们的蓝色主要是蓝色，但是蓝色和紫外线（UV）光在较低的气氛中大量散布，并且大多数先前的光学成像器对蓝色/UV灯都不敏感。新系统将部署在德克萨斯州，并结合来自非常低频率（VLF）/低频（LF）无线电接收器，闪电映射阵列（LMA）和传统气象数据的其他观察信息，以回答有关CTD Thunderstorm Coundary Coludy结构的电气和形态的关键问题。具体的研究问题包括：•CTD的领导者和流媒体动力学是什么，例如领导者的热温演化以及流媒体的电子能量？•领导者到流程器过渡区域的定量特征是什么？ •如何通过在云上方产生的LMA测量的非常高的频率（VHF）？ • 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 honestly of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.