Observed Size and Depth Distribution of Convective Cells

In order to understand the processes that control shallow to deep convection transition and growth of convective cells in the tropics, 3 wet seasons of C-Pol radar observations at Darwin Australia are analyzed. In scenes with small number of convective cells, the frequency of cells for a given cell area follows Boltzmann distribution, i.e., the number of cells drops exponentially with cell area at a rate proportional to the inverse of the number of cells in the radar domain implying weak cloud-cloud interactions. In contrast, in scenes with large number of convective cells, deviation from Boltzmann distribution is observed: more small cells and fewer large cells than is predicted by the distribution. Furthermore, for the same sizes, the cells which are members of the larger number of cells are generally deeper. The cloud-cloud and cloud-aggregate interactions responsible for the observed behavior and implications for the representation of cloud populations in scale-aware multi-cloud parameterizations will be discussed.