Lightning and Thunderstorm Studies

这是正在进行的研究的继续，旨在提高我们对闪电放电和放电过程以及雷暴的电气结构的理解。这些研究将利用在我们目前的NSF资助下开发的闪光连续宽带VHF干涉仪进行，沿着三维闪电测绘阵列（LMA）观测和快速和缓慢的电场变化测量。这些观测能够以前所未有的空间和时间细节来描述风暴中的闪电。研究的一个特别的初始重点将是获得地面实况观测，以验证最近发射的GOES-R卫星上的地球同步闪电测绘仪（GLM）从空间获得的闪电光学观测。智力优势：研究将跟进当前赠款中获得的结果，这些结果显示了高功率窄双极事件（NBE）是如何产生的-即由一种新认识到的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广，暗示可能所有的闪电放电都是由快速正过程引发的。 这项研究的目的是证实和扩展这些结果，从额外的观测NBE和闪光开始在佛罗里达风暴，目前正在获得丰富的肯尼迪航天中心。在这方面的一个特别的重点将是确定云内（IC）和负云对地（-CG）闪光的负击穿如何在启动后发展。另一个重点将是在高能量地面伽马射线闪光（TGFs）的来源和原因的家庭。越来越多的研究表明，TGF在IC和-CG闪光的初始阶段出现。犹他州大学的宇宙射线探测望远镜阵列（TA）正在进行的LMA和电场变化观测进一步证明了这一点，TA已经探测到了几个可能的向下TGF。将在位于墨西哥东南部海拔4公里的新建立的高海拔水切伦科夫伽马射线观测站进行进一步研究，在这种情况下将利用宽带干涉仪。不同的放电过程和闪电类型，如前兆，屏蔽，异常极性，和平静的放电将进行。更广泛的影响：GLM验证研究将有价值地帮助理解和解释即将到来的GLM观测，这将很快成为国家气象局业务的临近预报的主要部分。从KSC研究中获得的大量最先进的INTF和LMA数据将在KSC存档，并在线提供给其他机构的研究人员和学生进行分析。 作为GLM验证研究的一部分，华盛顿DC和Wallops VA LMA网络将连接在一起并向北扩展，以提供东海岸地区大范围的详细闪电覆盖。对樱岛火山的持续分析将为火山爆发的电气化过程提供见解。最后，将继续开发闪电绘图和相关技术，并将其传播给其他研究界和业务用户。

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.