Trace atmospheric SO_(2) measurement by multiwavelength curve-fitting and wavelength-optimized dual differential absorption lidar

摘要

We present a new differential absorption lidar (DIAL) method for atmospheric trace SO_(2) using multiwavelength curve fitting. With this method we use five wavelengths around a SO_(2) absorption peak and obtain SO_(2) and O_(3) concentrations by fitting their absorption cross sections to measured DIAL and null results. A SO_(2) concentration of 6 parts in 10~(9) (ppb) was obtained for an altitude of 1050 m with 150-m range resolution. In addition, we optimized the wavelengths for dual-DIAL SO_(2) measurement and demonstrated a high sensitivity of <0.5 ppb with 300-m range resolution. Comparison of these two methods is also presented.