Estimates of lightning NO<sub><i>x</i></sub> production based on high-resolution OMI NO<sub>2</sub> retrievals over the continental US

Abstract

Abstract. Lightning serves as the dominant source of nitrogen oxides (NOx=NO+NO2) in the upper troposphere (UT), with a strong impact on ozone chemistry and the hydroxyl radical production. However, the production efficiency (PE) of lightning nitrogen oxides (LNOx) is still quite uncertain (32–1100 mol NO per flash). Satellite measurements are a powerful tool to estimate LNOx directly compared to conventional platforms. To apply satellite data in both clean and polluted regions, a new algorithm for calculating LNOx has been developed that uses the Berkeley High-Resolution (BEHR) v3.0B NO2 retrieval algorithm and the Weather Research and Forecasting model coupled with chemistry (WRF-Chem). LNOx PE over the continental US is estimated using the NO2 product of the Ozone Monitoring Instrument (OMI) data and the Earth Networks Total Lightning Network (ENTLN) data. Focusing on the summer season during 2014, we find that the lightning NO2 (LNO2) PE is 32±15 mol NO2 per flash and 6±3 mol NO2 per stroke while LNOx PE is 90±50 mol NOx per flash and 17±10 mol NOx per stroke. Results reveal that our method reduces the sensitivity to the background NO2 and includes much of the below-cloud LNO2. As the LNOx parameterization varies in studies, the sensitivity of our calculations to the setting of the amount of lightning NO (LNO) is evaluated. Careful consideration of the ratio of LNO2 to NO2 is also needed, given its large influence on the estimation of LNO2 PE.

Quantification of lightning-produced NO<sub>x</sub> over the Pyrenees and the Ebro Valley by using different TROPOMI-NO<sub>2</sub> and cloud research products

“…It confirms that the uncertainty in the calculation of LNO x PE is still high, even when using high resolution measurements from TROPOMI. It also suggests that the LNO x PE vary substantially between different regions, as suggested by a comparison between our results and recent OMI-and TROPOMI-based LNO x PE over the USA (Lapierre et al, 2020;Allen et al, 2021a). This study also shows that differences in LNO x PE estimates can be caused by the different lightning systems.…”

“…We obtain 47 ± 33 (69 ± 34) mol NO x per flash using the TROP-KNMI research product and ENGLN (EUCLID) lightning data and 58 ± 33 (51 ± 25 mol NO x ) mol NO x per flash using TROP-DLR product and ENGLN (EUCLID) lightning data. Our mean LNO x PE estimates are slightly lower than the LNO x PE reported by Pickering et al (e.g., 2016); Allen et al (e.g., 2019); Zhang et al (e.g., 2020); Allen et al (e.g., 2021a) and a factor of ∼2 higher as determined by Lapierre et al (2020).…”

“…The sources of differences in the LNO x PE estimation evaluated in this study are summarized in Table 3. As discussed in previous studies (e.g., Pickering et al, 2016;Allen et al, 2019;Lapierre et al, 2020;Zhang et al, 2020;Allen et al, 2021a), there are other possible sources of uncertainty, such as the calculation of the AM F (LNO x profile type and lightning parameterization and NO x /NO 2 ratios in the simulations, scattering weights calculations) contributing to the uncertainty of about 30% or the method to select the OCP to be used for the definition of deep convection, contributing to the uncertainty of about 10%, or other systematic errors in the retrieval algorithms of TROPOMI. However, estimates of the influence of these parameters for the uncertainty of LNO x PE on the particular area of the Pyrenees is out of the scope of this paper, as we do not expect them to be dependent on the studied area.…”

“…Several authors have used OMI NO 2 measurements to estima the the LNO x PE in a case-based approach or systematically over different regions (Beirle et al, 2010;Marais et al, 2018), including midlatitude regions (Bucsela et al, 2019), tropical regions (Allen et al, 2019) and the U.S. (e.g., Pickering et al, 2016;Lapierre et al, 2020;Zhang et al, 2020;Allen et al, 2021a). Satellite-based measurements can help to estimate LNO x amounts over regions where aircraft campaigns are rare or to systematically investigate possible relationships between the characteristics of thunderstorms and LNO x over different geographical regions (Bucsela et al, 2019).…”

“…Therefore, we expect that during this time of the year a number of thunderstorms are active during the TROPOMI overpass (∼13:30 LT). We combine two TROPOMI research products with lightning data from the ENGLN (Zhu et al, 2017;Lapierre et al, 2020) and the EUropean Co-operation for LIghtning Detection (EUCLID) systems (Schulz et al, 2016). Apart from providing new valuable estimates of LNO x for Europe, this analysis will enable us to quantify the influence of using different lightning data sets and different TROPOMI NO 2 and cloud research products for the estimates of LNO x PE.…”