Nitrogen oxides are important chemical species in the atmosphere. For instance, the amount of nitrogen oxides controls whether ozone is produced or consumed in the oxidation of hydrocarbons. To assess the importance of industrial and other anthropogenic sources of nitrogen oxides, it is necessary to determine the natural production of these compounds. Lighting is suspected to be a significant natural source of nitrogen oxides. Yet, a major uncertainty exists in the quantity of nitrogen oxide produced during a flash. As a consequence, the biogeochemical cycling of nitrogen add nitrogen photochemistry in the natural atmosphere is also uncertain. This project seeks to determine experimentally the production of nitrogen oxides from nearby triggered lightning and also from more distant natural lightning. The project will measure with a chemiluminescent oxides of nitrogen analyzer the ratio of NO to NO2 in plumes from lightning flashes and will measure with an absorption spectrometer the cross sectional burden of NO2 in plumes from lightning flashes and in air parcels in which a number of lightning flashes have occurred. The project will lead to improved and more confined estimates of the natural production of nitrogen oxides by lightning and thus determine the importance of lightning as a global source.
