Contribution of Lightning-produced NOx to the European and Global NOx Budget: Results and Estimates from Airborne EULINOX Measurements

Airborne chemical in situ measurements were performed in thunderstorms during the field experiment EULINOX in July 1998. NOX (=NO+NO2) enhancements observed in the upper troposphere, which were caused by lightning or/and convective transport of polluted boundary layer air, were investigated in detail. Tracers for boundary layer air (CO2, CO, and O3) were used to determine the fraction of lightning-produced NOX and convective transported NOX in thunderstorms. The amount of lightning-produced NOX in comparison to aircraft emissions in the upper troposphere was estimated on the European and global scale.