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

Abstract

Abstract. Lightning is one of the major sources of nitrogen oxides (NOx) in the atmosphere, contributing to the tropospheric concentration of ozone and to the oxidising capacity of the atmosphere. Lightning produces between 2–8 Tg N per year globally and on average about 250 ± 150 mol NOx per flash. In this work, we estimate the moles of NOx produced per flash (LNOx production efficiency) in the Pyrenees (Spain, France and Andorra) and in the Ebro Valley (Spain) by using nitrogen dioxide (NO2) and cloud properties from the TROPOspheric Monitoring Instrument (TROPOMI) and lightning data from the Earth Networks Global Lightning Network (ENGLN) and from the EUropean Co-operation for LIghtning Detection (EUCLID). The Pyrenees is one of the areas in Europe with the highest lightning frequency and, due to its remoteness as well as experiencing very low NOx background, enables us to better distinguish the LNOx signal produced by recent lightning in TROPOMI NO2 measurements. We compare the LNOx production efficiency estimates for 8 convective systems in 2018 using two different sets of TROPOMI research products, provided by the Royal Netherlands Meteorological Institute (KNMI) and the Deutsches Zentrum für Luft- und Raumfahrt (DLR), respectively. According to our results, the mean LNOx production efficiency in the Pyrenees and in the Ebro Valley, using a three-hour chemical lifetime, ranges between 14 and 103 mol NOx per flash from the 8 systems. The mean LNOx production efficiency estimates obtained using both TROPOMI products and ENGLN lightning data differ by ∼23 %, while it differs by ∼35 % when using EUCLID lightning data. The main sources of uncertainty when using ENGLN lightning data are the estimation of background NOx that is not produced by lightning and the time window before the TROPOMI overpass that is used to count the total number of lightning flashes contributing to fresh-produced LNOx. The main source of uncertainty when using EUCLID lightning data is the uncertainty in the detection efficiency of EUCLID.

Sentinel-5P TROPOMI NO<sub>2</sub> retrieval: impact of version v2.2 improvements and comparisons with OMI and ground-based data

“…To this end special configuration settings, listed in the fourth column of Table 2 as "v2.1_test", are used: more outliers are accepted, but the number of spectral pixels flagged for saturation is limited somewhat because level-1b v1.0 spectra lack flagging for blooming. With these special settings, more ground pixels can be used -but with great care -for such lightning NO x studies (Allen et al, 2021;Pérez-Invernón et al, 2021;Zhang et al, 2021).…”

Lightning‐Produced Nitrogen Oxides Per Flash Length Obtained by Using TROPOMI Observations and the Ebro Lightning Mapping Array

“…The lifetime of NO x in the near field of convection can range between 2 hr and 2 days (Nault et al, 2017;Pickering et al, 2016). In this work, we assumed that the lifetime of NO x in the near field of convection is 5 hr, which is a consensus value in LNO x estimates (Allen, Pickering, Bucsela, et al, 2021;Pérez-Invernón et al, 2022).…”

“…We estimated the background-NO x (not produced by lightning) in the troposphere as the 30th and the 10th percentiles of the Vertical Column Density (VCD) tropospheric NO x over non-flashing pixels (pixels where there are not reported lightning flashes) satisfying the deep convective constraint that are not affected by the advected LNO x . We used the wind velocity and direction averaged between 200 hPa and 500 hPa provided by the European Center for Medium-Range Weather Forecasts (ECMWF) ERA5-reanalysis data set (Hersbach et al, 2020) to estimate the pixels that are influenced by the advected LNO x Pérez-Invernón et al (2022). The zonal component of the averaged wind is obtained by averaging the zonal component of the wind at all vertical points between the pressure levels 200 hPa and 500 hPa.…”

“…Among others, the final TROPOMI product includes the Slant Column Density (SCD) of NO 2 , the error of the SCD NO 2 , the quality assurance (QA) value, the stratospheric Vertical Column Density (VCD) of NO 2 , the stratospheric Air Mass Factor (AMF) of NO 2 , the Cloud Fraction (CF), Cloud Optical Thickness (COT), and the Optical Centroid Pressure (OCP) with a 3.5 km × 7.0 km horizontal resolution at nadir before 6 August 2019 and 3.5 km × 5.5 km thereafter. In this work, we used the TROP-DLR operational cloud and NO 2 research products (Liu et al, 2021;Loyola et al, 2018), that were recently applied by Pérez-Invernón et al (2022) for LNO x PE estimates. The TROP-DLR NO 2 research product is more appropriate for estimating LNO x than the operational TROPOMI NO 2 product because it produces more reliable cloud properties and NO 2 estimates over bright areas, such as thunderclouds.…”

“…In this work, we investigate the relationship between LNO x , lightning flash length and lightning flash rate. We used the Deutsches Zentrum für Luft-und Raumfahrt (DLR) TROPOMI operational cloud and TROPOMI research NO 2 products, also known as TROP-DLR (Liu et al, 2021;Loyola et al, 2018;Pérez-Invernón et al, 2022), combined with lightning measurements from the Ebro LMA (ELMA) (López et al, 2017;Pineda et al, 2016;van der Velde & Montanyà, 2013) and from the ENGLN (Lapierre et al, 2020;Zhu et al, 2017) for 16 cases. The ELMA system covers the Ebro Valley and the eastern coast of the Iberian Peninsula, an area with a high occurrence of thunderstorms during the end of the summer.…”