Lightning NOx Emissions: Reconciling Measured and Modeled Estimates With Updated NOx Chemistry

Lightning is one of the most important sources of upper tropospheric NO x ; however, there is a large spread in estimates of the global emission rates (2–8 Tg N yr −1 ). We combine upper tropospheric in situ observations from the Deep Convective Clouds and Chemistry (DC3) experiment and global satellite‐retrieved NO 2 tropospheric column densities to constrain mean lightning NO x (LNO x ) emissions per flash. Insights from DC3 indicate that the NO x lifetime is ~3 h in the region of outflow of thunderstorms, mainly due to production of methyl peroxy nitrate and alkyl and multifunctional nitrates. The lifetime then increases farther downwind from the region of outflow. Reinterpreting previous analyses using the 3 h lifetime reduces the spread among various methods that have been used to calculate mean LNO x emissions per flash and indicates a global LNO x emission rate of ~9 Tg N yr −1 , a flux larger than the high end of recent estimates.