Effective radius and droplet spectral width from in-situ aircraft observations in trade-wind cumuli during RICO

Cloud properties are derived from 10 Hz (about 10 m spatial distance) Fast-FSSP data in four different flights. The motivation comes from similar analyses of either aircraft data from stratocumulus clouds or remote-sensing data of tropical cumuli.

In the lowest few hundred meters, the standard deviation of the droplet size distribution σ r and the relative dispersion, the ratio of σ r and the mean radius, are similar to stratocumulus clouds, but they are significantly larger in the upper half of the cloud field depth. The frequency distribution of the effective radius is significantly narrower than in the remote-sensing observations in the middle and upper third of the cloud field.