| Summary: | Using multiyear satellite rainfall estimates, the distributions of the area, and the total rain rate of rain clusters over the equatorial Indian, Pacific, and Atlantic Oceans was found to exhibit a power law f[subscript s](s)~s[superscript -ζ[subscript s]], in which S represents either the cluster area or the cluster total rain rate and f[subscript s](s) denotes the probability density function of finding an event of size s. The scaling exponents ζS were estimated to be 1.66 ± 0.06 and 1.48 ± 0.13 for the cluster area and cluster total rain rate, respectively. The two exponents were further found to be related via the expected total rain rate given a cluster area. These results suggest that convection over the tropical oceans is organized into rain clusters with universal scaling properties. They are also related through a simple scaling relation consistent with classical self-organized critical phenomena. The results from this study suggest that mesoscale rain clusters tend to grow by increasing in size and intensity, while larger clusters tend to grow by self-organizing without intensification. Keywords: tropical rain clusters; self-organized criticality
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