Differences in Cloud Radar Phase and Power in Co- and Cross-Channel—Indicator of Lightning

Abstract

Thunderstorms and especially induced lightning discharges have still not been fully understood, although they are known to cause many casualties yearly worldwide. This study aims at filling the gap of knowledge by investigating the potential of phase and power of the co- and cross-channels of a vertical cloud radar to indicate lightning close to the radar site. We performed statistical and correlation analyses of vertical profiles of phase and power spectra in the co- and the cross-channel for 38 days of thunderstorms producing lightning up to 20 km from the radar in 2018–2019. Specifically, we divided the dataset into “near” and “far” data according to the observed distance of lightning to the radar and analyzed it separately. Although the results are quite initial given the limited number of “near” data, they clearly showed different structures of “near” and “far” data, thus confirming the potential of radar data to indicate lightning. Moreover, for the first time in this study the predictability of lightning using cloud radar quantities was evaluated. We applied a Regression Tree Model to diagnose lightning and verified it using Receiver Operating Characteristic (ROC) and Critical Success Index (CSI). ROC provided surprisingly good results, while CSI was not that good but considering the very rare nature of lightning its values are high as well.

Comparison of Cloud Structures of Storms Producing Lightning at Different Distance Based on Five Years Measurements of a Doppler Polarimetric Vertical Cloud Profiler

“…This study builds on our previous work by Sokol and Popová [12], which analyzed the cloud structure of several thunderstorms. The study used a novel approach and compared selected quantities measured by a vertically oriented cloud radar for lightning discharges that occurred near the radar position vs. far from the radar position.…”

“…In this study, similarly to Sokol and Popová [12], we analyze measurements of a Doppler polarimetric cloud radar operating at a frequency of 35 GHz, which is located at the Milešovka meteorological observatory. We also focus on cloud characteristics of thunderstorms, which produced electrical discharges in the vicinity of the radar.…”

“…In our previous work [12], we expressed the possibility of using a similarly performed analysis of radar data for the classification of a convective storm in terms of the occurrence of lightning in the close vicinity of the radar position. This study does not explicitly address this application, but the results also showed that some of the observed characteristics derived from the radar data differ for lightning storms that occur in the immediate vicinity of the radar versus storms where the lightning is farther from the radar.…”

Analysis of Two Convective Storms Using Polarimetric X-Band Radar and Satellite Data

“…Studies [7][8][9][10][11][12][13][14][15][16][17][18][19] provide examples of the use of both radar and satellite measurements for remote atmospheric research from recent times. These studies are focused on analysis of single events or try to find the general characteristics of studied events.…”

“…The FURUNO X-band weather radar is a research radar aimed at research on clouds and especially exploration of convective storms accompanied by lightning. Cloud electrification and lightning generation is our long-term research focus [16,17].…”