Trace gas imaging in the atmosphere with a Fabry-Pérot interferometer - a case study for sulfur dioxide

Atmospheric trace gas imaging allows the direct assessment of chemical dynamics, transport and mixing processes and is therefore desired in atmospheric physics and chemistry. For instance, the application of imaging measurements at trace gas point sources can substantially improve the determination of emission fluxes. The SO2 Camera is an imaging technique that is already applied at volcanoes. However, cross interferences of the detection principle can lead to significant uncertainties in the trace gas quantification. In this thesis an imaging technique employing a Fabry-Pérot interferometer (FPI) is introduced. In order to identify and quantify a trace gas species, the FPI's transmittance spectrum is matched to the molecule's absorption structures. The method was investigated for sulfur dioxide (SO2) in a model study. Moreover, a one pixel prototype was built as proof of concept. The detection limit reached with this simple prototype device is ca. 8.5*1016 molec/cm2 or 34 ppmm of SO2 in a 1 s measurement period. It could be shown, that compared to the SO2 Camera, the FPI technique has drastically reduced cross interferences to ozone, clouds and aerosol extinction. Finally, several implementations of the technique in an imaging instrument were proposed and discussed