Nitrogen oxides produced from lightning

Abstract

Independent measurements of nitrogen oxides (NO x = NO + NO 2 ) were made in proximity to lightning using both a chemiluminescent NO x analyzer and an absorption spectrometer (COSPEC) tuned to the NO 2 absorption at Langmuir Laboratory (elevation 3300 m), near Socorro, New Mexico. COSPEC data obtained from three separate lightning events, two from distant storms and one from direct observation of the plume from a single flash a few hundred meters away, yielded 4 to 10 × 10 26 molecules NO 2 /flash after normalizing to flashes at sea level. Measurements from the NO x analyzer during two different thunderstorms indicated that the ratio of NO to NO x can remain high (0.7–0.8±0.1) for several minutes after a flash. Combining the data from the COSPEC with the NO x analyzer yields a production rate of approximately 3×10 27 molecules N0 x /flash. If 100 flashes/second is an assumed global lightning flash frequency, this production rate becomes 100 TgN/yr (TgN/yr = 10 12 g nitrogen/yr) as an order of magnitude estimate.