Representation of Arctic mixed-phase clouds in the ECMWF Integrated Forecasting System during MOSAiC

Mixed-phase clouds are common in the Arctic atmospheric boundary layer and their representation is challenging for models. Recent studies suggest that the ECMWF Integrated Forecast System (IFS) shows too many cloudy periods in the Arctic in summer and generally misses the periods with clear skies, while in winter the cloudy state is underrepresented.We use ground-based remote sensing data from the MOSAiC campaign to assess systematic errors in modelled liquid cloud water over the whole MOSAiC period and combine this with more detailed analyses of selected cases.In addition, we perform sensitivity tests to identify ways to improve the parametrization for Arctic mixed-phase clouds in the IFS.We run cases in the Single Column Model (SCM) version of the IFS and investigate the representativity of model sensitivities in the SCM for the 3D model.