Statistical Frequency Analysis of Lightning Producing Storms During STEPS 2000

摘要

Most cloud-to-ground (CG) lightning lowers negative charge to ground, but roughly 10% of flashes are reversed and transfer positive charge to ground. A small number of storms produce predominately (greater than 50%) positive CG lightning, and recent studies have associated the occurrence of tornadoes, hail, and microbursts with these 'positive' storms. Much of this work has been centered on case studies. The use of case studies, however, is limited; the nature of case selection is subjective and possibly susceptible to researcher bias. This research presents a new method for addressing how a thunderstorm 'looks' from a statistical perspective, and is based on information readily available to researchers and operational forecasters alike. A statistical analysis of High Plains thunderstorms during the summer of 2000 was conducted as part of the Severe Thunderstorm Electrification and Precipitation Study (STEPS). WSR-88D NEXRAD and National Lightning Detection Network (NLDN) data sets were used to produce statistical radar reflectivity distributions based on cloud-to- ground (CG) lightning flash densities.