Model simulations of chemical effects of sprites in relation with observed HO 2 enhancements over sprite-producing thunderstorms

Winkler, Holger; Yamada, Takayoshi; Kasai, Yasuko; Berger, Uwe; Notholt, Justus

Recently, measurements by the Superconducting Submillimeter-Wave Limb Emission Sounder (SMILES) satellite instrument have been presented which indicate an increase in mesospheric inline-formulaHO2 above sprite-producing thunderstorms. The aim of this paper is to compare these observations to model simulations of chemical sprite effects. A plasma chemistry model in combination with a vertical transport module was used to simulate the impact of a streamer discharge in the altitude range 70–80 inline-formulakm, corresponding to one of the observed sprite events. Additionally, a horizontal transport and dispersion model was used to simulate advection and expansion of the sprite air masses. The model simulations predict a production of hydrogen radicals mainly due to reactions of proton hydrates formed after the electrical discharge. The net effect is a conversion of water molecules into inline-formulaH+OH. This leads to increasing inline-formulaHO2 concentrations a few hours after the electric breakdown. Due to the modelled long-lasting increase in inline-formulaHO2 after a sprite discharge, an accumulation of inline-formulaHO2 produced by several sprites appears possible. However, the number of sprites needed to explain the observed inline-formulaHO2 enhancements is unrealistically large. At least for the lower measurement tangent heights, the production mechanism of inline-formulaHO2 predicted by the model might contribute to the observed enhancements.



Winkler, Holger / Yamada, Takayoshi / Kasai, Yasuko / et al: Model simulations of chemical effects of sprites in relation with observed HO2 enhancements over sprite-producing thunderstorms. 2021. Copernicus Publications.


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