High Temporal-Resolution Analysis of Electrical Activity in a Severe Hailstorm Scanned Using Phased Array Radar

独特的高分辨率闪电和雷达数据是从大平原上空产生冰雹的非超级单体夏季雷暴中获取的。首席研究员将分析风暴的闪电活动与其动态和演化之间的关系；特别是调查闪电相对于降水增长的时间、闪电对大冰雹产生的响应，以及风暴电结构极性没有反转的原因的线索。这次冰雹是国家天气雷达试验台相控阵雷达 (NWRT PAR) 首批探测到的冰雹之一，该雷达支持对雷暴的雷达反射率特征进行快速采样（26 秒完成扇区体积扫描）。雷达反射率和速度数据揭示了风暴演变的前所未有的细节，远远优于传统天气监视雷达 1988-多普勒 (WSR-88D) 体积覆盖模式 (VCP) 提供的数据。俄克拉荷马州闪电测绘阵列 (LMA) 捕获了三维的高分辨率闪电位置数据。冰雹演变迅速，是两个系统在其整个生命周期中观测的理想位置。此外，它还产生了清晰的三体反射率尖峰，可用于跟踪大冰雹的出现和下降。因此，将有可能以无与伦比的时间和空间分辨率来检查闪电与其他演变的风暴特性的关系。智力优点：该研究将研究与风暴中闪电有关的一些问题。特别是，研究人员打算研究为什么这场风暴具有明显正常的电极性，而不是在其他类似风暴中观察到的异常、倒置类型。此外，还将调查冰雹、闪电活动和电气化之间的关系，以及有时在地面发生恶劣天气之前观察到的重大闪电活动之间的关系。预计使用更高时间分辨率的雷达数据将揭示与闪电发生和初始风暴动态相关的其他问题。更广泛的影响：预计从这项分析中，可以找到证据证明闪电活动是否可以在某些情况下用作即将发生的恶劣天气的前兆。有关这一点的假设将被直接检验，并可能对恶劣天气临近预报和发布预警产生影响。更一般地说，这项研究将有助于开发将三维闪电和高时间分辨率雷达数据结合起来的技术，用于研究和实际应用。

Unique high-resolution lightning and radar data have been acquired from a nonsupercell, hail producing summer thunderstorm over the Great Plains. The Principal Investigator will analyze the relationship between the storm's lightning activity and its dynamics and evolution; particularly to investigate the timing of lightning relative to precipitation growth, the lightning response to the production of large hail, and clues to the reasons why the polarity of the storm's electrical structure was not inverted. This hailstorm is one of the first to have been probed by the National Weather Radar Testbed Phased Array Radar (NWRT PAR), which supports rapid sampling (26 s to complete a sector volume scan) of the thunderstorm's radar reflectivity signatures. The radar reflectivity and velocity data reveal unprecedented detail of storm evolution, far superior to that provided by the traditional Weather Surveillance Radar 1988-Doppler (WSR-88D) Volume Coverage Patterns (VCPs). The Oklahoma Lightning Mapping Array (LMA) captured high-resolution lightning location data in three dimensions. The hailstorm evolved rapidly and was ideally placed for observation by both systems throughout its lifetime. Furthermore, it produced a clear three-body reflectivity spike that can be used to track the advent and descent of large hail. Thus, it will be possible to examine relationships of lightning to other evolving storm properties with unmatched temporal and spatial resolution. Intellectual Merit: The study will examine a number of questions relating to lightning in storms. In particular, the researchers intend to examine why the storm had an apparently normal electrical polarity instead of the abnormal, inverted type that has been observed in other similar storms. Additionally, the relationship between hail and lightning activity and electrification will be investigated, as well as the relationship between significant lightning activity sometimes observed to precede severe weather at the ground. Other questions relating to the onset of lightning in relation to the initial storm dynamics are anticipated to be revealed using the higher temporal-resolution radar data. Broader Impacts: It is anticipated from this analysis that evidence can be found for the credibility of whether lightning activity can be used in some situations as a precursor to imminent severe weather. Hypotheses about this will be directly examined and may have implications for severe weather nowcasting and the issuing of advanced warnings. More generally, this study will help in developing techniques to combine three-dimensional lightning and high-temporal resolution radar data for both research and practical applications.