Investigating the Periphery Region in Warm Cumulus Clouds

Abstract Warm cumulus clouds are key components of Earth's weather and climate systems, yet mixing processes within them and their interaction with their environment remain a major source of uncertainty in climate predictions. Based on adiabatic fraction (AF), such clouds can be divided into three regions: the adiabatic core, the skin (the diluted cloud edge), and the periphery, which lies between them, in terms of AF values. Despite its large volume and mass, the periphery is still poorly understood. This study shows that the periphery is equally supplied by air coming from the core and skin. However, periphery air flows mainly toward the skin, with limited transport into the core. The skin contributes to the periphery primarily through transport associated with the toroidal vortex. Each zone also exhibits distinct microphysical properties, including differences in droplet mean radius, variance, and relative dispersion.