Further Studies of Lightning Initiation, Propagation, and Evolution

闪电产生、传播和演化的进一步研究

• 批准号: 1427734
• 负责人: Maribeth Stolzenburg
• 金额: $ 77.9万
• 依托单位: University of Mississippi
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1427734&HistoricalAwards=false
• 关键词: Further; Studies; Lightning; Initiation; Propagation

Thunderstorms and their accompanying lightning flashes are responsible for a substantial number of casualties and property damage each year in the USA. However, we still do not understand the physical mechanisms that cause the first spark of a lightning flash or that allow the spark to grow into a conducting channel that travels to ground first through the cloud and then through the air. Intracloud flashes, those which move only inside and around a cloud (but not to ground), are a hazard for aircraft and space-bound rockets just after launch. This project aims to gain a better understanding of the important processes in lightning initiation, lightning propagation through cloud and air, and lightning evolution from a small spark to an electrical discharge that is miles long and can strike in multiple locations that are miles apart. The project will use existing data from a unique array of sensors.Intellectual Merit: This project will utilize data collected in summer 2011 around NASA Kennedy Space Center (KSC) in Florida, under a prior NSF award. The data come from a combination of six sensor sets, each of which reveals different information about a flash. Three systems were operated by KSC and provided data on the lightning paths (composed of short steps), the overall lightning charge, and lightning ground strike points. Two research arrays of electric field change sensors provided data on the location and amount of electric current for different parts of the flash; these currents can travel 50 yards to several miles in one-thousandth of a second or less. The sixth sensor was a high-speed video camera (operating at 50,000 fps) which yields detailed information on any luminous features of the lightning, including flash initiation and positive and negative charge motion. Seven scientific articles have already been published using this dataset and seven more are either under review or being written. However, the available multi-sensor dataset remains very rich and deep. For example, on one day (August 14, 2011) there were 25,500 intracloud and 1,700 cloud-to-ground flashes within 50 miles of KSC, and there are similarly good data on 15 storm days. Thus, there is much as-yet-unstudied data that can be used to learn new details about lightning initiation, propagation, and evolution. The project will be aided by many computer tools developed in a prior NSF award; these tools will enhance the data analysis from day one of this project. This project will also extend the previous dataset by including archived data from the Melbourne National Weather Service radar located near KSC. The additional radar data will allow comparisons of lightning initiation, propagation, and development to the thunderstorm reflectivity parameters (and other radar parameters) used by weather forecasters. Thus, the main intellectual merit of the study is that it will use existing data to advance the understanding of lightning mechanisms and better characterize the evolution of lightning structure throughout the thunderstorm lifecycle.Broader Impacts: Kennedy Space Center is located in a region with one of the largest numbers of lightning flashes per year; these flashes endanger the workers, space-bound vehicles, and special equipment at KSC. With its mission to safely launch rockets carrying satellites and astronauts, NASA is especially concerned about lightning. To continue reducing the lightning threat for the general public and for NASA, it is essential to better understand how lightning works; this project aims to advance that understanding. The project will be important for the development and training of several new scientists, including one post-doctoral researcher, one research associate, two graduate students, and two undergraduate physics students interested in scientific research. The training involves data analysis techniques that are specific to electromagnetic measurements of lightning as well as techniques that are generally applicable in many situations (including computer programming, computational modeling, and oral and written dissemination of results). Four of the eight anticipated project personnel are women. The results of this project will also be broadly disseminated in the peer-reviewed literature. Thus, the main broader impacts of this project are the potential reduction in lightning threats based on better understanding of lightning and the training of new and diverse scientists and engineers.

雷暴及其伴随的闪电每年在美国造成大量的人员伤亡和财产损失。然而，我们仍然不知道闪电产生第一个火花的物理机制，也不知道是什么让火花成长为一个传导通道，首先通过云层到达地面，然后通过空气。声内闪光是一种只在云层内部和周围移动(而不是地面)的闪光，对刚刚发射后的飞机和太空火箭来说是一种危险。该项目旨在更好地了解闪电引发、闪电在云和空气中的传播以及闪电从小火花到长达数英里的放电的演变过程中的重要过程，这些过程可以击中相距数英里的多个地点。该项目将使用来自一系列独特传感器的现有数据。智力优势：该项目将利用2011年夏天在佛罗里达州美国国家航空航天局肯尼迪航天中心(KSC)周围收集的数据，该数据是在之前的NSF奖下收集的。这些数据来自六个传感器组的组合，每个传感器组揭示了关于闪光灯的不同信息。KSC操作了三个系统，并提供了关于闪电路径(由短阶跃组成)、总闪电电荷和闪电接地点数的数据。两个电场变化传感器的研究阵列为闪光的不同部分提供了电流的位置和数量的数据；这些电流可以在千分之一秒或更短的时间内传播50码到几英里。第六个传感器是一台高速摄像机(运行速度为50000帧/秒)，它可以获得闪电的任何发光特征的详细信息，包括闪光引发和正负电荷运动。已经使用该数据集发表了七篇科学论文，另有七篇正在审查或正在撰写中。然而，可用的多传感器数据集仍然非常丰富和深入。例如，有一天(2011年8月14日)，在KSC周围50英里范围内发生了25,500次云内闪电和1,700次云对地闪电，在15个暴风雨日也有类似的良好数据。因此，有许多尚未研究的数据可以用来了解闪电引发、传播和演化的新细节。该项目将得到许多在之前的NSF奖项中开发的计算机工具的帮助；这些工具将从该项目的第一天起增强数据分析。该项目还将通过包括位于KSC附近的墨尔本国家气象局雷达的存档数据来扩展先前的数据集。额外的雷达数据将使闪电的产生、传播和发展与天气预报员使用的雷暴反射率参数(和其他雷达参数)进行比较。因此，这项研究的主要学术价值在于，它将利用现有的数据来促进对闪电机制的理解，并更好地描述雷暴整个生命周期中闪电结构的演变。广泛影响：肯尼迪航天中心位于每年闪电次数最多的地区之一；这些闪电危及KSC的工作人员、太空车辆和特殊设备。美国国家航空航天局的任务是安全地发射搭载卫星和宇航员的火箭，因此特别关注闪电。为了继续减少对普通公众和NASA的闪电威胁，必须更好地了解闪电是如何工作的；该项目旨在促进这一理解。该项目将对几名新科学家的发展和培训具有重要意义，其中包括一名博士后研究员、一名研究助理、两名研究生和两名对科学研究感兴趣的本科生。培训涉及专门针对闪电电磁测量的数据分析技术，以及在许多情况下普遍适用的技术(包括计算机编程、计算模型以及结果的口头和书面传播)。预期的8名项目人员中有4名是妇女。该项目的结果也将在同行评议的文献中广泛传播。因此，该项目的主要更广泛影响是，在更好地了解闪电和培训新的、多样化的科学家和工程师的基础上，有可能减少闪电威胁。

项目成果

On the Transition From Initial Leader to Stepped Leader in Negative Cloud‐to‐Ground Lightning

• DOI: 10.1029/2019jd031765
• 发表时间: 2020-02
• 期刊: Journal of Geophysical Research: Atmospheres
• 作者: M. Stolzenburg;T. Marshall;S. Karunarathne

Inception of subsequent stepped leaders in negative cloud-to-ground lightning

• DOI: 10.1007/s00703-019-00702-8
• 发表时间: 2019-10
• 期刊: Meteorology and Atmospheric Physics
• 影响因子: 2
• 作者: M. Stolzenburg;T. Marshall;S. Karunarathne

Modeling initial breakdown pulses of intracloud lightning flashes

模拟云内闪电的初始击穿脉冲

• DOI: 10.1016/j.atmosres.2021.105734
• 发表时间: 2021
• 期刊: Atmospheric Research
• 影响因子: 5.5
• 作者: Karunarathne, Nilmini;Marshall, Thomas C.;Karunarathne, Sumedhe;Stolzenburg, Maribeth
• 通讯作者: Stolzenburg, Maribeth