Further Severe Thunderstorm Electrification and Precipitation Study (STEPS): Continuing Investigations of Sprites and Their Parent Storms and Lightning Discharges

瞬变发光事件（TLEs），如红色精灵、蓝色喷流和精灵，是将对流层电活动与平流层和中间层联系起来的壮观现象。这些现象几乎总是与带正电的云对地闪电有关，这种现象比带负电的闪电发生的频率要低。已知有两种风暴类型会产生正闪电，即超级单体风暴和夜间中尺度对流系统。2000年初夏在堪萨斯州西部进行的STEPS项目（强雷暴通电和降水研究）提供了关于精灵和产生精灵的风暴的最全面的数据。FMA研究公司的Yucca Ridge野外站观测并录像了1200多个TLEs。这些数据是与STEPS上的其他风暴观测相结合收集的，包括双多普勒和极化雷达数据、飞机微物理测量、高分辨率闪电图和气球载电场测量。该奖项支持了STEPS对TLE观测结果的进一步分析，并使2003-2005年夏季的精灵监测得以继续。主要目标是：(1)表征闪电和精灵之间的关系；(2)对产生精灵和不产生精灵的风暴类型进行分类。方法是分析来自STEPS的TLE记录与雷达、闪电和其他数据的关系。结果将有助于我们更好地理解精灵形成的条件，从而更好地理解TLEs的物理性质。

Transient luminous events (TLEs) such as red sprites, blue jets, and elves are spectacular phenomena that link tropospheric electrical activity with the stratosphere and mesosphere. These phenomena are almost always associated with positive cloud-to-ground lightning, which occurs less frequently than negatively charged lightning. Two storm types are known to produce positive lightning, namely supercell storms and nocturnal mesoscale convective systems. The STEPS project (Severe Thunderstorm Electrification and Precipitation Study), conducted in western Kansas in the early summer of 2000, provided the most comprehensive data available on sprites and sprite-producing storms. More than 1200 TLEs were observed and video-recorded at the Yucca Ridge Field Station of FMA Research, Inc. These data were collected in association with other storm observations on STEPS, including dual-Doppler and polarimetric radar data, aircraft microphysical measurements, high-resolution lightning maps, and balloon-borne measurements of the electrical field. This award supports further analysis of the TLE observations from STEPS, and enables the continuation of sprite monitoring during the summers of 2003-2005. The main objectives are (1) to characterize the relationship between lightning and sprites; (2) to classify the storm types that do and do not produce sprites. The approach is to analyze the TLE records from STEPS in relation to the radar, lightning, and other data. Results will be an improved understanding of the conditions attendant to sprite formation, and hence the physics of TLEs.