NO signatures from lightning flashes

In situ measurements of cloud properties, NQ, and other trace gases were ma de in active thunderstorms by two research aircraft. Concurrent measurement s from a three-dimensional (3-D) VHF interferometer and the 2-D National Li ghtning Detection Network were used to determine lightning frequency and lo cation. The CHILL Doppler radar and the NOAA-WP-3D Orion X band Dopper rada r were also used to measure storm characteristics. Two case studies from th e (STERAO) Stratosphere-Troposphere Experiments: Radiation, Aerosols, and O zone project in northeastern Colorado during the summer of 1996 are present ed. Narrow spikes (0.11-0.96 km across), containing up to 19 ppbv of NO, we re observed in the storms. Most were located in or downwind of electrically active regions where the NO produced by lightning would be expected. Howev er, it was difficult to correlate individual flashes with NO spikes. A simp le model of the plume of NO from lightning is used to estimate NO productio n from the mean mixing ratio measured in these spikes. The estimates range from 2.0 x 10(20) to 1.0 x 10(22) molecules of NO per meter of flash length .