Spatial and Temporal Distributions of Lightning over Arizona from a Power Utility Perspective

Abstract

This study was designed to determine whether a spatially significant and temporally persistent variation in cloud-to-ground lightning frequency exists across the Salt River Project (SRP) region of central Arizona. Cloud-to-ground lightning data for 8 years from the Bureau of Land Management detection network were compiled to develop maps of lightning strike density across Arizona and the SRP region. In space, lightning frequency varied significantly across both of these topographically diverse regions. There was nearly five times more lightning over the high-altitude eastern border of the SRP region than over the lower western desert portion. The spatial pattern was consistent through time, so that more substantial lightning protection is warranted over the eastern SRP region than over the west. However, lightning frequency is highly variable from month to month and year to year on both the state and SRP scales, so that the value of newly installed lightning protection cannot be judged on experiences from a few years.