Detection of Upward Lightning by Lightning Location Systems

We report upward lightning observations in Sao Paulo city, SP, Brazil and compare them to data from Lightning Location System (LLS). These data are provided by 4 different networks from different technologies: BrasilDAT, RINDAT, Worldwide Lightning Location Network (WWLLN), and Earth Networks Global Lightning Network (ENGLN). Several upward flashes were observed from 2012-2014 using GPS time-stamped optical sensors and electric field measurements. These upward flashes were initiated from tall towers located at Jaragua Peak (70 and 130 m) and along Paulista Avenue (23 towers with heights between 50 and 220m). Time-correlated analyzes allowed to evaluate the network detection efficiency, intracloud (IC) / cloud-to-ground (CG) misclassification percentage, and location accuracy of the 4 different LLS. We will also show how different upward flash physical processes (leader initiation, recoil leaders, return strokes) are detected and classified by the distinct LLS technologies. Preliminary results show that in general, recoil leaders were not detected; on the other hand, several cases of return strokes and some cases of M-component were detected by one or more LLS networks.