Diversity of Tropical Cyclones Rapid Intensification.

The study investigates the rapid intensification (RI) of tropical cyclones (TCs) in the Northwestern Pacific. We found that rapid changes in the maximum wind speed (Vmax) and the minimum central pressure (Pmin) are not always concurrent. RI cases can be categorized into three types: (a) RIv, only Vmax strengthens rapidly; (b) RIp, only Pmin decreases rapidly; (c) RIpv, rapid changes in Vmax and Pmin occur concurrently. At the onset of RI, RIv‐type TCs exhibit the weakest intensity and the smallest size, with deep convection concentrated in the inner‐core region; RIp‐type TCs are characterized by the strongest cyclone intensity and the largest outer‐core size, with strong convection covering the inner‐ and outer‐core regions; RIpv‐type TCs show moderate intensity, size, and convection distribution. For RIpv, significant strengthening of wind profile is concentrated in the inner‐core region, while for RIp it is more prominent in the outer‐core. Plain Language Summary: The rapid intensification (RI) of tropical cyclones (TCs) continues to pose challenges in both operational forecasting and scientific research. The maximum wind speed (Vmax) and the minimum central pressure (Pmin) are two commonly used TC intensity indicators. In most of existing studies, one single indicator (usually Vmax) is used to investigate the RI process. Whether there is a difference between RI cases defined by 24‐hr strengthening of Vmax and 24‐hr deepening of Pmin is an issue deserving discussion. The study found that rapid changes in Vmax and Pmin are not always concurrent. In the cases where only Vmax strengthens rapidly, the outer‐core size of TC expands slowly. While in the cases where only Pmin deepens rapidly, the enhancement of outer circulation is distinctive. Since the Pmin, as an integral variable, reflects TC information of both the intensity and the size, RI cases classified via these two commonly used indicators (Vmax and Pmin) could help us further understand the relationship between TC intensity and size. Key Points: Rapid changes in the maximum wind speed (Vmax) and the minimum central pressure (Pmin) are not always concurrent in tropical cyclones (TCs)TCs that only experience a rapid increase in Vmax (RIv) tend to have a significantly weaker lifetime maximum intensityThe evident expansion of the outer circulation occurs in TCs of which only Pmin deepens rapidly (RIp) [ABSTRACT FROM AUTHOR]