On the surface of clouds

Abstract

The cloud-environment mixing process is considered in terms of fractal properties of the cloud-clear air interface. The fractal dimension of the cloud surface is estimated from high-resolution airborne data. The value obtained is D = 2.55 in a range of scales from at least 10 m to over 1000 m with the possibility of even greater extension. This differs significantly from values obtained in shear-generated, well-developed, and homogeneous turbulence. The distribution of filament sizes of cloudy and clear air and estimates of the cloud surface and characteristic time of mixing process are given. -Authors