Estimates of Lightning NOx Production based on High Resolution OMI NO2 Retrievals over the Continental US

Lightning is an important source of nitrogen oxides (NO_x = NO + NO₂ ) in the upper troposphere, with strong impact on ozone and the hydroxyl radical production. However, the production efficiency (PE) of lightning nitrogen oxides (LNO_x) is still quite uncertain (32 — 1100 mol NO per flash). Satellites measurements are a powerful tool to estimate LNO_x directly as compared to conventional platforms. To apply satellite data without geographic restrictions, a new algorithm for calculating LNO_x has been developed based on the new Berkeley High Resolution (BEHR) v3.0B NO₂ and the Weather Research and Forecasting-Chemistry (WRF-Chem) model. We estimate LNO_x PE over the continental US using the NO₂ product of the Ozone Monitoring Instrument (OMI) satellite and the Earth Networks Total Lightning Network (ENTLN) data. Focusing on the summer season during 2014, we find that lightning NO₂ (LNO₂) PE is 29 ± 14 mol NO₂ flash^-1 and 8 ± 4 mol NO₂ stroke^-1 while LNO_x PE is 79 ± 38 mol NO_x flash^-1 and 22 ± 12 mol NO_x stroke^-1. Results reveal that former methods are more sensitive to background NO₂ and neglect many below-cloud LNO₂. As the LNO_x parameterization varies in studies, we evaluate the sensitivity of our calculations to the setting of LNO amounts.