A Fabry–Perot interferometer based camera for two-dimensional mapping of SO 2 distributions

We examine a new imaging method for the remote sensing of volcanic gases, which relies on the regularly spaced narrow-band absorption structures in the UV-VIS of many molecules. A Fabry–Perot interferometer (FPI) is used to compare the scattered sunlight radiance at wavelengths corresponding to absorption bands with the radiance at wavelengths in between the bands, thereby identifying and quantifying the gas. In this first theoretical study, we present sample calculations for the detection of sulfur dioxide (SO2). Optimum values for the FPI set-up parameters are proposed. Further, the performance of the FPI method is compared to SO2 cameras. We show that camera systems using a FPI are far less influenced by changes in atmospheric radiative transfer (e.g. due to aerosol) and have a great potential as a future technique to examine emissions of SO2 (or other gases) from volcanic sources and other point sources.