Comparative Study on Entrainment‐Mixing Mechanisms Between Cumulus Cores and Edges Based on Aircraft Observations

Abstract Entrainment‐mixing processes between clouds and their environment significantly impact the microphysical, thermodynamical, and dynamical properties of clouds. However, quantitative observational analysis of different entrainment‐mixing mechanisms between cumulus cores and edges remains lacking. This study provides the quantitative analysis of such mechanisms in cumulus cores versus edges using aircraft observations from the Rain in Cumulus Over the Ocean project. Results show that cores have larger liquid water content, larger cloud droplets, and smaller entrained droplet‐free air parcels, consequently yielding a larger homogeneous mixing degree ( ψ ) and a smaller Damköhler number (, the ratio of mixing time scale to droplet evaporation time scale). ψ is 0.13 higher and is 3.3 lower in the cores compared to the edges. Furthermore, core‐edge differences in ψ are analyzed under varying environmental and cloud conditions. Smaller cloud width, weaker in‐cloud vertical velocity, lower environmental relative humidity, and lower aerosol concentration all reduce ψ and enhance the core‐edge ψ contrast. The results offer insights into the theoretical understanding and parameterizations of entrainment‐mixing mechanisms in the cores and edges of cumulus clouds.