On the Relationship Between Condensed Water Content and Liquid-Ice Mixing Homogeneity in Mixed-Phase Stratiform Clouds

As a key factor influencing the cloud life cycle and radiative properties, liquid-ice mass partitioning remains a major source of uncertainties in modeling mixed-phase clouds. One of the unresolved problems is that liquid-ice mixing is highly inhomogeneous, but it has not been well understood and quantified for parameterization. In this study, the liquid-ice mixing homogeneity (χ) is quantified using the information-theoretic entropy based on airborne measurements. It is demonstrated that χ is positively correlated with the condensed water content (CWC). Cloud regions with low χ are consist of liquid and ice clusters. With the increase in χ, the size and frequency of continuous mixed-phase clusters increase. For a given CWC, χ is lower at relatively warm temperatures as sedimentation of large ice crystals can enhance the inhomogeneity. The strong positive relationship between CWC and χ indicates CWC should be considered when parameterizing the liquid-ice mixing in models.