Lightning and Thunderstorm Studies

这是正在进行的研究的继续，目的是提高我们对闪电放电和放电过程以及雷暴的电气结构的了解。研究将利用我们目前的NSF资助下开发的闪光连续宽带甚高频干涉仪，以及三维闪电映射阵列(LMA)观测和快慢电场变化测量进行。这些观测能够以前所未有的细节描述风暴中的闪电，无论是在空间上还是时间上。这些研究的一个特别的初始重点将是获得地面真实观测，以验证从太空对闪电的光学观测，这将由最近发射的GES-R卫星上的地球同步闪电映射器(GLM)获得。智力价值：这些研究将跟进目前拨款中获得的结果，这些结果表明高功率窄双极事件(NBE)是如何产生的--即一种新认识的被称为快速正击穿的现象。进一步的研究表明，快速击穿发生的强度范围很大，这暗示着所有闪电放电都可能是由快速正过程引发的。这项研究的目的将是证实和推广这些来自佛罗里达风暴中的NBE和闪电引发的额外观测结果，目前肯尼迪航天中心正在大量获得这些结果。在这方面，一个特别的焦点将是确定大范围内(IC)和负的云对地(-CG)闪电在启动后如何发展的负分解。另一个焦点将是集中在高能地面伽马射线闪电(TGFs)的来源和原因上。越来越多的证据表明，TGFs发生在IC和-CG闪光的初始阶段。犹他大学的宇宙线探测望远镜阵列(TA)正在进行的LMA和电场变化观测进一步证明了这一点，该望远镜阵列探测到了几个可能向下的TGFs。在这种情况下，将在位于墨西哥东南部4公里高度的新建立的高海拔水切伦科夫(HAWC)伽马射线天文台进行其他研究，在这种情况下，将利用宽带干涉仪进行研究。将进行不同的放电过程和闪电类型，如前兆、屏蔽、异常极性和间歇放电。广泛的影响：GLM验证研究将有助于理解和解释即将到来的GLM观测，这将很快成为美国国家气象局业务的主要部分。从KSC研究中获得的大量最先进的INTF和LMA数据将在KSC存档，并在线提供，供其他机构的调查人员和学生分析。作为GLM验证研究的一部分，华盛顿特区和沃洛普斯VA LMA网络将连接在一起并向北扩展，以在东海岸地区的大片地区提供详细的闪电覆盖。正在进行的对樱岛火山的分析将为火山喷发的电气化过程提供见解。最后，将继续向其他研究界和业务用户开发和传播闪电测绘和相关技术。

This is a continuation of ongoing research aimed at improving our understanding of lightning discharges and discharge processes, as well as the electrical structure of thunderstorms. The studies will be conducted utilizing the flash-continuous broadband VHF interferometer developed under our current NSF grant, along with 3-D Lightning Mapping Array (LMA) observations and fast and slow electric field change measurements. The observations are able to characterize lightning inside storms with unprecedented detail, both spatially and temporally. A particular initial focus of the studies will be obtaining ground-truth observations for validating optical observations of lightning from space, to be obtained by the Geosynchronous Lightning Mapper (GLM) on board the recently launched GOES-R satellite.Intellectual Merit:The studies will follow up on results obtained in the current grant that showed how high-power narrow bipolar events (NBEs) are produced - namely by a newly-recognized phenomenon called fast positive breakdown. Further investigation showed that the fast breakdown occurs with a wide range of strengths, hinting that potentially all lightning discharges are initiated by the fast positive process. The research will be aimed at substantiating and extending these results from additional observations of NBEs and flash initiation in Florida storms, currently being obtained in abundance at Kennedy Space Center. A particular focus in this regard will be determining how the negative breakdown of intracloud (IC) and negative cloud-to-ground (-CG) flashes develops subsequent to initiation.Another focus will be to home in on the source and cause of highly energetic terrestrial gamma ray flashes (TGFs). TGFs are increasingly being shown to occur during the initial stages on IC and -CG flashes. This has been further demonstrated by ongoing LMA and electric field change observations at the University of Utah's cosmic ray-detecting Telescope Array (TA), which has detected several possible downward TGFs. Additional studies, in this case utilizing the broadband interferometer, are to be obtained at the newly-established High Altitude Water Cherenkov (HAWC) gamma ray observatory, situated at 4 km altitude in southeastern Mexico. Different discharge processes and lightning types, such as precursor, screening, anomalous polarity, and lull discharges will be conducted.Broader Impacts:The GLM validation studies will valuably assist in understanding and interpreting the upcoming GLM observations, which will quickly become a major part of nowcasting in National Weather Service operations. The voluminous, state-of-the-art INTF and LMA data obtained from the KSC study will be archived at KSC and made available online for analysis by investigators and students at other institutions. As part of the GLM validation study, the Washington DC and Wallops VA LMA networks will be joined together and expanded northward to provide detailed lightning coverage over a large extent of the east coast region. Ongoing analysis of the Sakurajima volcano will be providing insights into the electrification processes of volcanic eruptions. Finally, development and dissemination of lightning mapping and related technology to other research communities and operational users will be continued.