Evaluation of visible satellite images from AROME-Austria as preparation for assimilating visible observations

Assimilating visible satellite observations has become an increasingly active research topic and has been shown to provide valuable information for improving weather forecasts. The assimilation of these observations, however, is challenging due to operator deficiencies and model deficiencies in the representation of clouds. Our work focuses on evaluating the potential of the RTTOV observation operator to simulate visible satellite images in the convection-permitting AROME-Austria model, which is operational at Geosphere Austria. Specifically, we examine the systematic deviations caused by operator and model errors in all-sky conditions. In cloudy conditions, we build on findings from preceding studies and conduct sensitivity tests to evaluate model equivalents with modified operator settings. In clear-sky conditions, we aim to evaluate and mitigate the systematic deviations caused by orographic shadowing and high-albedo surfaces with the help of an advanced visible operator developed by DWD. A summer month of 3-hourly forecasts from 6 UTC to 18 UTC provides the basis for this analysis. Our findings aim to address operator deficiencies and model inconsistencies, laying the groundwork for integrating visible observations as a new observation type into the AROME-Austria model.