Mixed phase clouds are difficult to model drivers of the climate system. This study presents novel, long-term observations of mixed-phase clouds in the Arctic using advanced remote sensing techniques, offering unprecedented insights into cloud microphysics and aerosol-cloud interactions. Leveraging the unique MOSAiC expedition measurements, for the first time, it provides height-resolved statistical analysis of mixed-phase cloud properties, with a particular focus on the characteristics of liquid phase clouds. The combination of novel lidar and radar retrieval techniques enables precise monitoring of phase transitions, ice formation via immersion freezing, and the influence of aerosol activation. Given the key role of mixed-phase cloud in regulating the Arctic energy balance and their significance in climate models, this study provides essential empirical data to help improve cloud representation and parameterizations. Based on these observations, the authors recommend to implement time-dependent parameterization schemes to properly account for the evolution of long-lasting mixed-phase cloud layers in models.