Studies of New Elements for Global Electric Circuit Models

该项目开发了改进的模型，其中包括最近的实验数据，以大大提高对雷暴作为地球全球电路发电机的理解。第1部分涉及开发一个球形几何模型的一个现实的雷暴嵌入在一个现实的，进行大气。该风暴是模拟层的稳定状态的电流，调整，以重现典型的观察到的垂直电场（E）从不同的风暴类型的配置文件。然后，该模型适用于大型中尺度对流系统（MCSs），更典型的小风暴，并通过使用适当的垂直电场剖面未屏蔽的对流上升气流。第1部分的结果将显示不同类型的风暴如何在全球电路中驱动地球和电离层之间的不同电流量。在第2部分中，模型被扩展到处理与闪电相关的瞬态电流。瞬变电流模型应用于MCS和小雷暴，结果将添加到第1部分。通过这项工作的相对重要性的瞬态电流在全球电路将推导出。最后，将进行一个全球范围的检查，将这些改进的估计的几个“雷暴组件”的电路，包括中尺度对流系统，小雷暴，未屏蔽的对流核心，和云上的瞬变引起的闪电。每个组件的相对贡献将估计。该项目的整体智力价值来自于结合所有建议的模拟结果的贡献MCS，小风暴，及其相关的瞬变，估计的数量和类型的雷暴同时发生在地球上。这种合成将提供一个最先进的估计，是在全球电路驱动的所有同时雷暴。这个新的估计值将与地球仪的晴天部分发生的放电电流进行比较。由此，可以确定雷暴在全球电路中的总体重要性以及地球上的总体电荷。对全球环流的其他贡献者，如非雷暴雨云的重要性的估计也是可能的。这个项目的更广泛的影响部分来自于在整个研究过程中扩展和扩大的国际合作。研究人员、研究生和本科生将与俄罗斯应用物理研究所的知名科学家和年轻科学家、研究生和本科生密切合作开展这项工作。主要的俄罗斯合作者（其中一人是最近的博士。候选人）和一名研究生将在美国访问研究人员的实验室。这项合作还涉及理论等离子体物理学家（俄罗斯合作者）与实验大气物理学家（美国研究人员）的整合。这种交流将为两个群体带来新的调查和发现方法。该项目的另一个更广泛的影响涉及科学家和学生的性别多样性：一名美国调查人员和至少一名美国学生是女性，女性在物理学和大气物理学中仍然是一个代表性不足的群体。指导，培训和教育的本科生和研究生参与将提高他们的能力，成为独立的研究人员在这个或另一个科学领域。结果的出版和传播将有助于更好地了解全球电路，而全球电路通过全球雷暴活动与全球气候密切相关。

This project develops improved models that incorporate recent experimental data to give a substantially improved understanding of thunderstorms as generators in the Earth's global electric circuit. Part 1 involves developing a spherical geometry model of a realistic thunderstorm embedded in a realistic, conducting atmosphere. The storm is modeled with layers of steady state currents that are adjusted to reproduce typically observed vertical electric field (E) profiles from different storm types. The model is then applied to large mesoscale convective systems (MCSs), to more typical small storms, and to unscreened convective updrafts by using appropriate vertical electric field profiles. The results of Part 1 will show how different types of storms drive different amounts of current between the Earth and the ionosphere in the global circuit. In Part 2 the model is expanded to handle transient currents associated with lightning flashes. The transient current model is applied to MCSs and to small thunderstorms, and the results will be added to those of Part 1. Through this work the relative importance of transient currents in the global circuit will be deduced. Finally, a global scale examination will be undertaken that incorporates these improved estimates of the several 'thunderstorm components' in the circuit, including mesoscale convective systems, small thunderstorms, unscreened convective cores, and above-cloud transients caused by lightning flashes. The relative contribution of each of these components will be estimated.The overall intellectual merit of this project derives from combining all of the proposed modeling results for the contribution of MCSs, small storms, and their associated transients, with estimations of the number and type of thunderstorms occurring simultaneously on the Earth. This synthesis will provide a state-of the-art estimate of the current that is driven in the global circuit by all simultaneous thunderstorms. This new estimate will be compared to the discharging currents that occur in the fair weather portion of the globe. From this, the overall importance of thunderstorms in the global electric circuit and the overall charge on the Earth can be determined. An estimate of the importance of other contributors to the global circuit, such as non-thunderstorm shower clouds, will also be possible.The broader impacts of this project derive partly from the international collaboration that areextended and expanded throughout the studies. The investigators, graduate students, and undergraduate students will conduct the work in close collaboration with established scientists and young scientists, graduate students, and undergraduate students at the Institute for Applied Physics in Russia. The primary Russian collaborators (one of whom is a recent Ph.D. Candidate) and one graduate student will visit the investigators' laboratory in the U.S. for extended periods. This collaboration also involves an integration of theoretical plasma physicists (Russian collaborators) with experimental atmospheric physicists (U.S. investigators). This exchange will lead to new methods of investigation and discovery for both groups. Another broader impact of the project involves the gender diversity of the scientists and students: one of the U.S. investigators and at least one of the U.S. students are female, and women remain an underrepresented group in physics and in atmospheric physics, especially. Mentorship, training, and education of the undergraduate and graduate students involved will enhance their abilities to become independent researchers in this or another field of science. Publication and dissemination of the results will contribute to better understanding of the global electrical circuit, which is intimately tied to global climate through the global thunderstorm activity.