Radiative transfer in clouds with small-scale inhomogeneities: Microphysical approach

[1] Several recent publications have indicated that cloud droplets belonging to a particular size range may tend to cluster by forming small random particle groups imbedded in an otherwise uniform cloud. To analyze radiative transfer in clouds with such small-scale inhomogeneities, we invoke the concepts of statistical electromagnetics. We show that as long as the assumptions of ergodicity and spatial uniformity hold, one can still apply the classical radiative transfer equation in which the participating extinction and phase matrices are obtained by averaging the respective singleparticle matrices over all the particles constituting the cloud. This result implies that comparisons of in situ and remote-sensing retrievals of the cloud-particle size distribution can be problematic and should be performed with caution. Citation: Mishchenko, M. I. (2006), Radiative transfer in clouds with small-scale inhomogeneities: Microphysical approach, Geophys. Res. Lett., 33, L14820, doi:10.1029/2006GL026312.