Simultaneous profiling of O 3 and NO 2 in the lower troposphere by multiwavelength differential absorption lidar

Abstract

Vertical concentration profiles of O<SUB>3</SUB> and NO<SUB>2</SUB> in the lower troposphere were measured simultaneously using a multi wavelength differential absorption lidar (DIAL) system based on a pair of Nd:YAG pumped dye lasers each capable of emitting two wavelength on alternate pulses. A mixture of Rhodamine 590 and Rhodamine 610 dyes and second harmonic generation was used to generate wavelengths 288.2 nm and 293. 5 nm for O<SUB>3</SUB> measurement, and sum frequency mixing of LDS765 dye laser radiation with Nd:YAG fundamental was used to generate wavelengths 448.1 nm and 446.8 nm for NO<SUB>2</SUB> measurement. O<SUB>3</SUB> profiles of approximately 30-50 ppb and NO<SUB>2</SUB> profiles of 0-20 ppb were obtained for vertical range 1500-2500 m. The measurement error was estimated to be < 6 ppb for 150 m range resolution, or < 0.9 ppm-m, for both O<SUB>3</SUB> and NO<SUB>2</SUB>.