Classification and dynamics of tropical clouds by their fractal dimension

The fractal dimension estimated as the area–perimeter relation constitutes a tool for the characterization of clouds. In this article, we apply it for the first time to study the separation of cirrus and cumulonimbus in the C aribbean area. Based on satellite data, we show that the two types can be differentiated by their area–perimeter ratio as follows: D Ci = 1.37 ± 0.02 for cirrus, and D Cb = 1.18 ± 0.05 for cumulonimbus. We also show that the ‘global’ area–perimeter ratio can be used to determine the composition of the cloud field. Moreover, we are able to quantify, through the area–perimeter ratio, the transformation of cumulonimbus into cirrus. Our findings have potential applications for the automatic classification of clouds, and for the understanding of their formation processes.