NO plume mapping by laser-radar techniques

Mapping of NO plumes by using laser-radar techniques has been demonstrated with a mobile differential absorption lidar system. The system was equipped with a narrow-linewidth Nd:YAG-pumped dye laser that, with doubling and mixing, generated pulse energies of 3-5 mJ at 226 nm, with a linewidth of 1pm. This permitted range-resolved measurements of NO, with a range of about 500 m. The detection limit was estimated to 3 microg/m(3), with an integration interval of 350 m. Spectroscopic studies on the gamma(0, 0) bandhead near 226.8 nm were performed with 1-pm resolution, and the differential absorption cross section was determined to be (6.6 +/- 0.6) x 10(-22) m(2), with a wavelength difference of 12 pm.