Why Flash Type Matters: A Statistical Analysis

• Published in: Geophysical research letters 2017-09, Vol.44 (18), p.9505-9512
• Main Authors: Mecikalski, Retha M., Bitzer, Phillip M., Carey, Lawrence D.
• Format: Article
• Language: English
• Subjects: flash size; flash type; hybrid flash; Lightning; Lightning flashes; LNOx; Return strokes (lightning); Statistical analysis; Statistical methods; Storms
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2017GL075003

While the majority of research only differentiates between intracloud (IC) and cloud‐to‐ground (CG) flashes, there exists a third flash type, known as hybrid flashes. These flashes have extensive IC components as well as return strokes to ground but are misclassified as CG flashes in current flash type analyses due to the presence of a return stroke. In an effort to show that IC, CG, and hybrid flashes should be separately classified, the two‐sample Kolmogorov‐Smirnov (KS) test was applied to the flash sizes, flash initiation, and flash propagation altitudes for each of the three flash types. The KS test statistically showed that IC, CG, and hybrid flashes do not have the same parent distributions and thus should be separately classified. Separate classification of hybrid flashes will lead to improved lightning‐related research, because unambiguously classified hybrid flashes occur on the same order of magnitude as CG flashes for multicellular storms. Key Points Hybrid flashes have statistically different size and altitude distributions from intracloud and cloud‐to‐ground flashes Hybrid flashes initially have electric field properties similar to intracloud flashes but produce a return stroke Due to their larger sizes, hybrid flashes produce ≥159% more nitrogen oxides than intracloud and cloud‐to‐ground flashes