Abstract:Based on the high resolution infrared satellite data, this study focuses on the evolution of Typhoon Bill (8807) from tropical depression to tropical storm and shows the complicated vortices self-organizations during the development of the tropical storm.It is indicated that the self-organized cloud clusters could range from 10 to 100 000 km2. Besides of the two scenarios from the ideal numerical experiments, there exits another scenario for the behavior of the self-organized cloud clusters. The larger cloud cluster could be divided into small clusters which partially merge with other cloud clusters. The new-merged cloud cluster may either strengthen or weaken, which depends on the embedding environment or the supplements of other cloud clusters. By using two-dimensional Fourier analysis, it is evident that the development of the tropical storm (8807) experiences two stages. The first is the multi-vortices coexistence, during which the energy transitions occur frequently between systems with various directions and scales. The other is the single vortex development stage, during which the pattern of the spectral density contours maintain stable. Fractal dimension calculations demonstrate that the cloud clusters related to the development of the tropical storm are more regular than those of previous studies, and the fractal dimension is smaller. Furthermore, fractal dimension varies considerably when the critical temperature is different. Specifically, the fractal dimension is smaller as the critical temperature is lower.