Numerical Studies of Electrification and Lightning in Severe Thunderstorm Electrification and Precipitation Study (STEPS) Storms

一个先进的数值云模式将被用来模拟在2000年夏季的强雷暴通电和降水研究(STEPS)中观测到的风暴类型。三维动态模拟模型包括详细的微物理、电气和闪电参数化，并在模拟几种类型的雷暴时生成逼真的风暴和闪电。在电气化研究中，步骤中的观察是最完整的之一。它们包括极化雷达测量、双多普勒测量、闪电测绘阵列获取的三维闪电模式、通过仪表式气球和一架穿透风暴的飞机获得的现场云层和电学测量，以及来自流动中尺度网络的地面观测。这些数据将与模拟进行比较，以提高对严重风暴中运动学、降水产生和带电之间相互作用的理解。要调查的专题包括：(1)垂直空气运动和降水对闪电产生的影响；(2)风暴类型(如单单体、多单体、超级单体)对闪电率和其他闪电特性的影响；(3)伴随产生异常闪电活动的条件，如闪电率极高或正的云对地闪电。预计这项研究将导致使用闪电数据帮助诊断和预报恶劣天气的方法。

An advanced numerical cloud model will be used to simulate the types of storms observed in the Severe Thunderstorm Electrification and Precipitation Study (STEPS) of the summer of 2000. The three-dimensional dynamic simulation model includes detailed microphysical, electrical, and lightning parameterizations and produces realistic storms and lightning in simulations of several types of thunderstorms. Observations during STEPS were among the most complete ever taken for electrification studies. They included polarimetric radar measurements, dual-Doppler measurements, three- dimensional lightning flash patterns obtained by the Lightning Mapping Array, in-situ cloud and electrical measurements obtained by instrumented balloons and a storm-penetrating aircraft, and surface observations from a mobile mesoscale network. The data will be compared with simulations to improve the understanding of interactions among kinematics, precipitation production, and electrification in severe storms. Examples of the topics to be investigated are (1) the influence of vertical air motions and precipitation on the production of lightning; (2) the influence of storm type (e.g., unicell, multicell, supercell) on flash rates and other lightning characteristics; (3) conditions attendant to the production of unusual lightning activity, such as exceptionally high flash rates or positive cloud-to-ground lightning. It is expected that the research will lead to ways of using lightning data to help diagnose and forecast severe weather.