Sizes of cloud droplets and cloud droplet residues near stratus cloud base

Measurements on cloud droplet size-distribution and the relationship between sizes of cloud droplets and their residues were carried out near the base of stratus clouds on Mt. Tsukuba, Japan. The size distribution of cloud droplets always had high number concentrations of small droplets < 2.5 mu m radius. The sizes of droplet residues had some dispersion for cloud droplets < 6 mu m radius. However, no systematic difference in the physico-chemical properties of residues was recognized in the droplet residue size relation. Not only an influence of solute but also a low growth of cloud droplets due to the reduction in supersaturation will yield a size distribution broadened toward the small droplet size end.