Examination of varying mixed-phase stratocumulus clouds in terms of their properties, ice processes and aerosol-cloud interactions between polar and midlatitude cases: An attempt to propose a microphysical factor to explain the variation

This study examines the ratio of ice crystal number concentration (ICNC) to cloud droplet number concentration (CDNC), which is ICNC/CDNC, as a microphysical factor that induces differences in cloud development, its interactions with aerosols and impacts of ice processes on them among cases of mixed-phase clouds. This examination is performed using a large-eddy simulation (LES) framework and one of efforts toward a more general understanding of mechanisms controlling those development and impacts in mixed-phase clouds. For the examination, this study compares a case of polar mixed-phase clouds to that of midlatitude mixed-phase clouds with weak precipitation. It is found that ICNC/CDNC plays a critical role in making differences in cloud development with respect to the relative proportion of liquid and ice mass between the cases by affecting in-cloud latent-heat processes. Note that this proportion has an important implication for cloud radiative properties and thus climate. It is also found that ICNC/CDNC plays a critical role in making differences in clouds and their interactions with aerosols and impacts of ice processes on them between the cases by affecting in-cloud latent-heat processes. Findings of this study suggest that ICNC/CDNC can be a simplified general factor that contributes to a more general understanding of mixed-phase clouds and roles of ice processes and aerosols in them and thus, to the development of more general parameterizations of those clouds and roles.