Oklahoma Lightning Mapping Array: Detection Efficiency, Mapping Large Sets of Data, and the Beginning of a Total Lightning Climatology

Abstract:

The Oklahoma Lightning Mapping Array (OKLMA) has collected the time and location of very
high frequency (VHF) radiation sources produced by all types of lightning in central Oklahoma since the spring of 2003. The detection efficiency of the OKLMA decreases with distance from the center of the LMA, which causes a false maximum in sources over the network when working with very large data sets. Using five months worth of data and assuming a VHF source detection efficiency of 100% over the network, a map of detection efficiency at different ranges is presented. Two methods of eliminating the bias of source detection over the network are explored: a normalization method based on the decreasing VHF power of detected sources with range and a flash-sorting method. Although both methods yield similar results, the flash sorting method is chosen for future climatology studies because it is more readily understood and is already in use throughout the community in case studies and lightning jump algorithms. The first maps and time series of total lightning over central Oklahoma for a 10-year period are presented.