Investigation of 3D-effects for UV/vis satellite observations of volcanic plumes

<p>Usually, horizontally homogenous atmospheric properties are assumed for the analysis of satellite observations of atmospheric trace gases. While for most atmospheric quations, this simplification causes only small to moderate errors, for the observation of volcanic plumes this neglecting 3D effects can lead to very large errors. These errors (3D effects) can become especially important for satellite observations with high spatial resolution like TROPOMI on Sentinel-5 Precursor.</p> <p>Different 3D effects were recently investigated for volcanic plumes by Wagner et al. (2022). It was found that especially the so-called light mixing effect can lead to a strong underestimation of the true trace gas amount of volcanic plumes if 1D atmospheric properties were assumed in the retrieval. For strong absorbers like SO₂, the underestimation can further be increased by the saturation effect. In that study, different 3D effects were separately studied for idealised plumes.</p> <p>Here we investigate the combined 3D effects for realistic volcanic plumes using radiative transfer simulations. We focus on two scenarios: first on observations of the ascending part of the plume above a volcano and second on the horizontally advected plume at a distance from the volcanic vent. In addition to the 3D effect of the volcanic plume (trace gases and aerosols), also the influence of the surface elevation is investigated.</p> <p>&#160;</p> <p>Wagner, T., Warnach, S., Beirle, S., Bobrowski, N., Jost, A., Pu&#311;&#299;te, J., and Theys, N.: Investigation of 3D-effects for UV/vis satellite and ground based observations of volcanic plumes, Atmos. Meas. Tech. Discuss. [preprint], https://doi.org/10.5194/amt-2022-253, in review, 2022.</p>