Francisco Javier Perez-Invernon

Lightning is one of the main sources of NO _x in the Earth's atmosphere, yet there is considerable variability in NO _x production during thunderstorms. In this study, we combined optical lightning data from the Meteosat Third Generation (MTG) Lightning Imaging (LI) instrument, which provides information on the occurrence rate and physical characteristics of lightning flashes, measurements from an extended Lightning Mapping Array (LMA) consisting of 24 sensors, lightning measurements from the Lightning Location System (LLS) of the Meteorological Service of Catalonia (MSC), and TROPOspheric Monitoring Instrument (TROPOMI) cloud and NO ₂ research products to investigate lightning NO _x emissions in the Ebro Valley (Spain). WRF-Chem simulations were used to calculate the necessary air mass factors and to subtract the NO _x not produced by lightning from the TROPOMI measurements, allowing a more accurate estimation of lightning-induced NO _x . We found positive relationships between lightning-produced NO _x per flash and several lightning properties, including flash channel length, radiance, footprint, duration and the length of the optical continuous signal detected from space. These results highlight the importance of combining detailed lightning observations with atmospheric modeling to quantify NO _x emissions from thunderstorms.

Lightning is one of the main sources of NOₓ in the Earth’s atmosphere, yet there is considerable variability in NOₓ production during thunderstorms. In this study, we combined optical lightning data from the Meteosat Third Generation (MTG) Lightning Imaging (LI) instrument, which provides information on the occurrence rate and physical characteristics of lightning flashes, measurements from an extended Lightning Mapping Array (LMA) consisting of 24 sensors, lightning measurements from the Lightning Location System (LLS) of the Meteorological Service of Catalonia (MSC), and TROPO-spheric Monitoring Instrument (TROPOMI) cloud and NO₂ research products to investigate lightning NOₓ emissions in the Ebro Valley (Spain). WRF-Chem simulations were used to calculate the necessary air mass factors and to subtract the NOₓ not produced by lightning from the TROPOMI measurements, allowing a more accurate estimation of lightning-induced NOₓ. We found positive relationships between lightning-produced NOₓ per flash and several lightning properties, including flash channel length, radiance, footprint, duration and the length of the optical continuous signal detected from space. These results highlight the importance of combining detailed lightning observations with atmospheric modeling to quantify NOₓ emissions from thunderstorms.

Lightning is one of the main sources of NOₓ in the Earth’s atmosphere, yet there is considerable variability in NOₓ production during thunderstorms. In this study, we combined optical lightning data from the Meteosat Third Generation (MTG) Lightning Imaging (LI) instrument, which provides information on the occurrence rate and physical characteristics of lightning flashes, measurements from an extended Lightning Mapping Array (LMA) consisting of 24 sensors, lightning measurements from the Lightning Location System (LLS) of the Meteorological Service of Catalonia (MSC), and TROPO-spheric Monitoring Instrument (TROPOMI) cloud and NO₂ research products to investigate lightning NOₓ emissions in the Ebro Valley (Spain). WRF-Chem simulations were used to calculate the necessary air mass factors and to subtract the NOₓ not produced by lightning from the TROPOMI measurements, allowing a more accurate estimation of lightning-induced NOₓ. We found positive relationships between lightning-produced NOₓ per flash and several lightning properties, including flash channel length, radiance, footprint, duration and the length of the optical continuous signal detected from space. These results highlight the importance of combining detailed lightning observations with atmospheric modeling to quantify NOₓ emissions from thunderstorms.

Lightning is one of the main sources of NOₓ in the Earth’s atmosphere, yet there is considerable variability in NOₓ production during thunderstorms. In this study, we combined optical lightning data from the Meteosat Third Generation (MTG) Lightning Imaging (LI) instrument, which provides information on the occurrence rate and physical characteristics of lightning flashes, measurements from an extended Lightning Mapping Array (LMA) consisting of 24 sensors, lightning measurements from the Lightning Location System (LLS) of the Meteorological Service of Catalonia (MSC), and TROPO-spheric Monitoring Instrument (TROPOMI) cloud and NO₂ research products to investigate lightning NOₓ emissions in the Ebro Valley (Spain). WRF-Chem simulations were used to calculate the necessary air mass factors and to subtract the NOₓ not produced by lightning from the TROPOMI measurements, allowing a more accurate estimation of lightning-induced NOₓ. We found positive relationships between lightning-produced NOₓ per flash and several lightning properties, including flash channel length, radiance, footprint, duration and the length of the optical continuous signal detected from space. These results highlight the importance of combining detailed lightning observations with atmospheric modeling to quantify NOₓ emissions from thunderstorms.

Lightning is one of the main sources of NOₓ in the Earth’s atmosphere, yet there is considerable variability in NOₓ production during thunderstorms. In this study, we combined optical lightning data from the Meteosat Third Generation (MTG) Lightning Imaging (LI) instrument, which provides information on the occurrence rate and physical characteristics of lightning flashes, measurements from an extended Lightning Mapping Array (LMA) consisting of 24 sensors, lightning measurements from the Lightning Location System (LLS) of the Meteorological Service of Catalonia (MSC), and TROPO-spheric Monitoring Instrument (TROPOMI) cloud and NO₂ research products to investigate lightning NOₓ emissions in the Ebro Valley (Spain). WRF-Chem simulations were used to calculate the necessary air mass factors and to subtract the NOₓ not produced by lightning from the TROPOMI measurements, allowing a more accurate estimation of lightning-induced NOₓ. We found positive relationships between lightning-produced NOₓ per flash and several lightning properties, including flash channel length, radiance, footprint, duration and the length of the optical continuous signal detected from space. These results highlight the importance of combining detailed lightning observations with atmospheric modeling to quantify NOₓ emissions from thunderstorms.

Lightning is one of the main sources of NOₓ in the Earth’s atmosphere, yet there is considerable variability in NOₓ production during thunderstorms. In this study, we combined optical lightning data from the Meteosat Third Generation (MTG) Lightning Imaging (LI) instrument, which provides information on the occurrence rate and physical characteristics of lightning flashes, measurements from an extended Lightning Mapping Array (LMA) consisting of 24 sensors, lightning measurements from the Lightning Location System (LLS) of the Meteorological Service of Catalonia (MSC), and TROPO-spheric Monitoring Instrument (TROPOMI) cloud and NO₂ research products to investigate lightning NOₓ emissions in the Ebro Valley (Spain). WRF-Chem simulations were used to calculate the necessary air mass factors and to subtract the NOₓ not produced by lightning from the TROPOMI measurements, allowing a more accurate estimation of lightning-induced NOₓ. We found positive relationships between lightning-produced NOₓ per flash and several lightning properties, including flash channel length, radiance, footprint, duration and the length of the optical continuous signal detected from space. These results highlight the importance of combining detailed lightning observations with atmospheric modeling to quantify NOₓ emissions from thunderstorms.

We analyze lightning optical emissions and their production of different chemical species with particular emphasis on and . We calculate synthetic lightning spectra with inputs from an electrodynamical model of hot air lightning plasmas. The electrodynamical model calculates the temporal and radial evolution of plasma parameters and chemical species. We analyze 26 lightning‐like discharges modeled between 0 and 16 km altitude, varying the input energy between 4 and 200 J/cm, the initial radius, the initial mass, and the humidity. We use a simplified model to estimate the peak current corresponding to each input energy. The ratio of the production of to obtained in this study for saturated air ranges between and strongly influenced by air humidity, which is in better agreement with laboratory measurements than previous modeling results. We calculate the synthetic optical emissions of an exposed lightning section. We compare the simulated peaks in the 777.4 nm and the 337.0 nm photon fluxes with observations of shallow and exposed lightning by the Atmosphere–Space Interactions Monitor (ASIM). Our simulations of hot lightning plasmas result in negligible thermal (due to ions) 337.0 nm optical emissions below 30 kA peak current. This indicates that 337.0 nm optical emissions detected by ASIM are mainly produced by lightning streamers instead of by thermally produced ionic lines in lightning. Finally, we found that the hot lightning channel produces a significant amount of Vacuum Ultraviolet photons that can travel outside the channel to produce non‐negligible amounts of OH by photodissociation of water.

Summer thunderstorms are important precursors of wildfires in the United States, accounting for a significant portion of the total burned area. Wildfire forecast systems can benefit from investigating the preferential meteorological conditions, cloud‐to‐ground lightning characteristics, and fire danger indices of lightning‐induced wildfires. In this study, we investigate the meteorological conditions during the occurrence of fire‐igniting strokes, the value of fire danger indices, the presence of continuing currents detected from space, and the polarity of the strokes. Previous studies have independently investigated lightning candidates reported by lightning location systems or space‐based instruments; however, we integrated data from both sources in our analysis. We found that the cloud‐to‐ground lightning ignition efficiency of fire‐igniting strokes with continuing current is slightly higher than that of cloud‐to‐ground lightning without continuing current. In particular, we report that strokes with continuing currents lasting more than 10 ms may have a higher potential to produce wildfires than cloud‐to‐ground strokes without continuing currents when the conditions for the initial spread of the fire are less favorable. Our results suggest that the polarity of the strokes does not significantly influence the likelihood of a fire.