HO Generation Above Sprite‐Producing Thunderstorms Derived from Low‐Noise SMILES Observation Spectra

Abstract

No direct observational evidence of sprite‐produced active radicals has been presented owing to the difficulty of observing a small event area in the nighttime mesosphere, whereas sprite chemical models have indicated that sprite discharge locally affects the atmospheric composition. We present the first observational evidence of a HO 2 production above sprite‐producing thunderstorms from the coincidence of temporal‐spatial observations of HO 2 spectra, sprite events, and thunderstorms by two space instruments, a submillimeter‐wave limb spectrometer and ultraviolet/visible Imager and a ground‐based very low frequency radiation lightning detection network. A total of three areas was identified with enhanced HO 2 levels of approximately 10 25 molecules. A chemical sprite model indicates an increase in HO 2 in the considered altitude region; however, the predicted production due to a single sprite event is smaller than the observed enhancement. Our observational results suggest that sprites potentially contribute 1% of nighttime background HO 2 generation at altitudes of 75–80 km globally.

Experimental Radial Profiles of Early Time (<4 μs) Neutral and Ion Spectroscopic Signatures in Lightning‐Like Discharges

“…Corona discharges in thunderclouds are especially frequent in the Tornado alley in North America (Soler et al., 2021) where the airborne observations (Brune et al., 2021) reporting important production of OH and HO 2 were carried out. In addition, recent submillimeter‐wave spectroscopy observations (Yamada et al., 2020) indicate that streamer coronas in sprites (Gordillo‐Vázquez, 2008; Gordillo‐Vázquez et al., 2018; Sentman et al., 2008) occurring in the mesosphere are responsible of mesospheric OH and HO 2 enhancements. Previous observations (Bozem et al., 2014; Zahn et al., 2002) relate sudden O 3 enhancements found in thunderstorms with the occurrence of subvisible (corona) discharges in thunderclouds.…”

Model simulations of chemical effects of sprites in relation with observed HO&lt;sub&gt;2&lt;/sub&gt; enhancements over sprite-producing thunderstorms

“…Electric-field-driven processes additionally included compared to the model of Winkler and Notholt (2014). The reaction rate coefficients in air depending on the reduced electric field strength were calculated with the Boltzmann solver BOLSIG+ (Hagelaar and Pitchford, 2005) using cross-section data for H 2 O (Itikawa and Mason, 2005) and for H 2 (Yoon et al, 2008…”

Chemical Activity of Low Altitude (50 km) Sprite Streamers

“…Optical diagnostic methods of sprites are used to estimate the plasma characteristics of sprites (Kuo et al., 2019; Malagón‐Romero et al., 2019; Pérez‐Invernón, Luque, Gordillo‐Vazquez, et al., 2018) including the possibility that they could (or not) locally heat up the surrounding atmosphere (Gordillo‐Vázquez et al., 2018; Parra‐Rojas, Passas, et al., 2013; Pasko et al., 1998). In turn, chemical and electrodynamical models of sprites indicate that they can produce nitrogen oxides (NO x = NO + NO 2 ) (Enell et al., 2008; Evtushenko et al., 2013; Gordillo‐Vázquez, 2008, 2010; Gordillo‐Vázquez et al., 2012; Hiraki et al., 2008; Luque & Gordillo‐Vázquez, 2011a; Sentman et al., 2008; Winkler & Nothold, 2014), nitrous oxide (N 2 O) (Parra‐Rojas et al., 2015; Pérez‐Invernón et al., 2020) and hydrogen oxide radicals (HO x = H + OH + HO 2 ) (Winkler et al., 2021; Yamada et al., 2020) in the mesosphere and the lower‐ionosphere possibly playing a role in the upper atmospheric budget of ozone. Sentman et al.…”

“…and hydrogen oxide radicals (HO x = H + OH + HO 2 ) (Winkler et al, 2021;Yamada et al, 2020) in the mesosphere and the lower-ionosphere possibly playing a role in the upper atmospheric budget of ozone. Sentman et al (2008) estimated a production of 5 × 10 19 molecules of NO per sprite-streamer between altitudes 65 and 75 km.…”