Knowledge Bank

Currently available $SO2$ spectra are used to predict the performance of various proposed techniques for remote sensing of $SO2$ in the atmosphere. Calculations are presented which indicate that range-resolved (100 m) measurements of $SO2$ concentrations greater than 30 ppm can be made using a Differential Absorption Lidar (DIAL) operating near $2500 cm-1$. For $SO2$ concentrations between 400 ppb and 30 ppm, range-resolved measurements can be made by the DIAL technique at a wavelength of approximately 300 nm. These Lidar systems would be useful for monitoring emissions from power plant smokestacks. In addition, the 300 nm wavelength region could be used to make a column content of $SO2$ at concentrations above 10 ppb, typical of an urban environment. Further calculations indicate that measurements of stratospheric $SO2$ concentrations with a balloon-borne solar occultation spectrometer would be marginal.