资源环境科技发展态势分析平台

A series of vertical cross sections taken through a small mesoscale convective system observed over Florida by the dual-polarimetric SMART radar were combined with VHF radiation source locations from a lightning mapping array (LMA) to examine the lightning channel propagation paths relative to the radar-observed ice alignment signatures associated with regions of negative specific differential phase (KDP). Additionally, charge layers inferred from analysis of LMA sources were related to the ice alignment signature. It was found that intracloud flashes initiated near the upper zero-KDP boundary surrounding the negative KDP region. The zero-KDP boundary also delineated the propagation path of the lightning channel with the negative leaders following the upper boundary and positive leaders following the lower boundary. Very few LMA sources were found in the negative KDP region. We conclude that rapid dual-polarimetric radar observations can diagnose strong electric fields and may help identify surrounding regions of charge.

Plain Language Summary Lightning is the second leading cause of meteorologically related deaths and results in billions of dollars in damage annually. Determining when a cloud becomes electrified may lead to improved warnings of lightning activity. In this paper, we show that polarimetric radar observations can reveal the location of strong electric fields in the middle to upper levels of thunderstorms. Moreover, we show that the leaders associated with intracloud lightning flashes propagate around the edges of the radar-indicated regions of high electric fields. Additionally, it was found that the main charge regions within thunderstorms follow the outer contours of the area of radar-indicated high electric fields. With the development of rapid-scanning polarimetric radar, it may be possible in the future to diagnose likely propagation paths of intracloud electrical discharges within thunderstorms.