SMuK 2021 – scientific programme
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UP: Fachverband Umweltphysik
UP 4: Measurement Techniques & Miscellaneous
UP 4.1: Talk
Friday, September 3, 2021, 11:00–11:15, H7
Imaging of Formaldehyde in the Atmosphere — •Alexander Nies1, Christopher Fuchs1, Jonas Kuhn1,2, Nicole Bobrowski1,2, and Ulrich Platt1,2 — 1Institute of Environmental Physics, Heidelberg University, Germany — 2Max Planck Institute for Chemistry, Mainz, Germany
Monitoring of atmospheric traces gases by imaging techniques is essential for the understanding of physical and chemical dynamics of the atmosphere. Hyperspectral imaging in the UV-VIS range allows highly selective measurements of several trace gases simultaneously, but scanning is necessary for image acquisition resulting in a low spatio-temporal resolution. Non-dispersive imaging techniques, e.g. SO2 cameras, reach high spatial and temporal resolution, but due to their strongly restricted spectral information they are limited to high abundances of SO2 only. Combining the benefits of both approaches using a Fabry-Perot-Interferometer in a filter camera setup enhances spectral information by matching its periodic transmission to the narrowband absorption structures of the target trace gas and leading to reduced cross interferences. The technique has been demonstrated for SO2 and we present a case study for HCHO in the atmosphere with a sensitivity of 4.7·10−16molec/cm2. Because of the similar absorption structures of HCHO and BrO in the UV wavelength range, the same instrument can be used for BrO measurements (for instance, highly abundant in volcanic plumes). Usually HCHO and BrO have no common sources, and therefore, potential cross sensitivities are only a minor problem. The calculated sensitivity for BrO is 1.6·10−14molec/cm2.