Radar Reflectivity and Altitude Distributions of Lightning as a Function of IC, CG, and HY Flashes: Implications for LNOx Production

Abstract

Two dimensional (2‐D) histogram distributions of lightning flashes relative to radar reflectivity and altitude were created using a total of 41,180 intercloud/intracloud (IC) flashes, 3,326 cloud‐to‐ground (CG) flashes, and 4,349 hybrid (HY) flashes that originated in multicells; 111,479 IC flashes, 8,588 CG flashes, and 11,699 HY flashes that originated in mesoscale convective systems; and 91,283 IC flashes, 3,023 CG flashes, and 7,872 HY flashes that originated in supercells that occurred over northern Alabama and southern Tennessee. It was shown that although CG flashes initiate and propagate at the same altitude irrespective of storm type, IC flashes could have differences of up to 10 °C, while for HY flashes these differences increased to up to 20 °C relative to storm type. Further, IC, CG, and HY flashes propagated in lower reflectivities than where they initiated, while CG flashes initiated and propagated within higher reflectivities than IC and HY flashes. HY flashes were also twice as large as IC flashes and ~40% larger than CG flashes, and flashes that originated in mesoscale convective systems had larger overall sizes as compared to multicells and supercells. When comparing the new 2‐D histogram distributions to the legacy distributions used for the calculation of lightning‐produced nitrogen oxides (LNOx), it was shown that the new distributions perform much better, with higher Pearson product moment correlation coefficient values and much lower root‐mean‐square errors. These new distributions are thus more appropriate to use when modeling LNOx and will lead to more accurate LNOx estimations than using the legacy distributions.

Time Evolution of Satellite‐Based Optical Properties in Lightning Flashes, and its Impact on GLM Flash Detection

“…However, early assessment studies have shown that the GLMs have a higher detection efficiency for CG flashes than IC flashes (Bitzer, 2019; Yoshida, 2019). The so‐called hybrid flashes with extensive IC components as well as connections to ground complicate this interpretation and may sometimes be as common as CG flashes that exclusively have channels in the lower part of the cloud (Mecikalski et al, 2017; Mecikalski & Carey, 2018).…”

Lightning Location, NOx Production, and Transport by Anomalous and Normal Polarity Thunderstorms

“…Furthermore, Ott et al () found that the final advected LNOx distribution varies with storm environment. In fact, several studies discuss the need for continued research focused on quantifying the impact of various environmentally driven storm structures on the production of LNO x (e.g., Barthe & Barth, ; Mecikalski & Carey, ; Ott et al, ). Unfortunately, little research has been conducted to investigate the impact of environmental characteristics on LNO x production, explaining why it became one of the main goals of the Deep Convective Clouds and Chemistry (DC3) campaign in 2012 (Barth et al, ).…”

Introduction to the Deep Convective Clouds and Chemistry (DC3) 2012 Studies

“…Analyses of storms in northern Alabama revealed that vertical distributions of intracloud flashes did not have the expected bimodal initiation distribution and that hybrid flashes (i.e., flashes with both intracloud and cloud-to-ground components) were consistently larger in size than intracloud or cloud-to-ground flashes , 2018a. and Mecikalski and Carey (2018b) found that these three types of flashes do not have the same parent distribution and therefore should be treated separately in lightning-NO x parameterizations. Ott et al (2010) noted that the vertical distribution of lightning-NO x differed in midlatitude and subtropical storms, but little research has been done to examine the effect of the storm environment on lightning-NO x production.…”

“…Analyses of storms in northern Alabama revealed that vertical distributions of intracloud flashes did not have the expected bimodal initiation distribution and that hybrid flashes (i.e., flashes with both intracloud and cloud‐to‐ground components) were consistently larger in size than intracloud or cloud‐to‐ground flashes (Mecikalski & Carey, , ). Mecikalski et al () and Mecikalski and Carey () found that these three types of flashes do not have the same parent distribution and therefore should be treated separately in lightning‐NO x parameterizations.…”