Tropical Cyclone Intensification and Fullness: The Role of Storm Size Configuration

The relationships between the intensification rate (IR) and the size configuration of tropical cyclones (TCs) are investigated. Theoretically, the intensity, size configuration, and relative vorticity of TCs are intrinsically linked. TC fullness (TCF) is used to quantify the size configuration of TCs and can be expressed as the product of the critical fullness (TCF0) and the ratio of fullness (Rf). TCF0 represents the fundamental constraint on size configuration shared by TCs at a given intensity and is the lower limit of fullness, whereas Rf reveals a TC's unique wind structural feature. Intermediate TCF0 (similar to 0.55), moderate Rf (similar to 1.4), and thus high TCF (similar to 0.8) collectively facilitate the occurrence of a large IR of TC. Obtaining a stable and moderate Rf at low TCF0 favors the subsequent intensification of a TC. The TCF-TCF0 diagram is proposed to illustrate the co-evolution of TC size configuration and intensity, and to reveal how they modulate intensification.