@article{efb9e2b445784c168a0c8049c67960f7,
title = "HO 2 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 HO2 production above sprite-producing thunderstorms from the coincidence of temporal-spatial observations of HO2 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 HO2 levels of approximately 1025 molecules. A chemical sprite model indicates an increase in HO2 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 HO2 generation at altitudes of 75–80 km globally.",
author = "T. Yamada and Sato, {T. O.} and T. Adachi and H. Winkler and K. Kuribayashi and R. Larsson and N. Yoshida and Y. Takahashi and M. Sato and Chen, {A. B.} and Hsu, {R. R.} and Y. Nakano and T. Fujinawa and S. Nara and Y. Uchiyama and Y. Kasai",
note = "Funding Information: We thank P. Baron, H. Sagawa, J. Mendrok, Y. Hiraki, T. Iino, and R. Lehmann for valuable discussions. T. Yamada was supported by a Grant-in-Aid for JSPS Research Fellows (15J11279). Y.?K., Y.?T., M.?S., N.?Y., and Y.?N. conceived the concept of the paper. T.?Y. wrote the first draft of the manuscript and performed the data analysis with help from R.?L. for ARTS and K.?K., T.?O.?S., S.?N., Y.?U., and T.?F. for SMILES. H.?W. conducted chemical model. T.?A. conducted analysis of ISUAL data, and T.?A., A.?B.?C., and R.?R.?H. provided ISUAL data. All authors discussed the results and commented on the manuscript at all stages. We also thank the Editor and the reviewers for their valuable comments and suggestions for improving the manuscript. The authors declare that they have no competing financial interests. Data and materials availability: The JEM/SMILES mission is a joint project of the Japan Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT). The SMILES Level-2 research data are available to users from the website (http://smiles.nict.go.jp/pub/data/index.html). The sprite detection data of the ISUAL CCD imager are available to users from the website (http://formosat.tw/nspo_esok/events_f2_isual.php). Additional data related to this paper may be requested from the authors. The ARTS model is provided and supported by a community of developers and users and available via the www.radiativetransfer.org website. The WWLLN (http://www.wwlln.com) product was provided by R. Holzworth of the University of Washington. Publisher Copyright: {\textcopyright}2020. The Authors.",
year = "2020",
month = feb,
day = "16",
doi = "10.1029/2019GL085529",
language = "English",
volume = "47",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "3",
}