The Influences of Environmental States on the Rapid Growth of Tropical Cyclone Outer Size over the Western North Pacific

다국어 초록 (Multilingual Abstract)

In this study, the 95th percentile of 24-h change rate of the radius of the 17 m s −1 winds (R17) was used to defi ne the rapid growth (RG) of tropical cyclone (TC) outer size. The statistical results show that the environmental sea surface temperature (SST), specifi c humidity (SH), temperature ( T ) and wind fi elds (WND) of the RG cases are signifi cantly different from those of the non-rapid change cases over the western North Pacifi c during 2004–2022. The infl uences of the environmental SST, SH, T and WND on the RG of TC R17 were investigated by adopting high-resolution HWRF model and a series of idealized numerical experiments. The simulation results show that the largest relative contribution to the RG of TC R17 is from environmental WND (accounts for 27.4%), followed by environmental SH (accounts for 6.3%) and SST (accounts for 1.9%). The relative contribution of the environmental T to the RG of TC R17 is negative (−4.4%), which is unfavorable for the RG of TC R17. Then, a schematic diagram of the possible main physical processes that the environmental SST, SH, T and WND aff ect the RG of TC R17 was summarized. The environmental SST, SH, T and WND may ultimately aff ect the RG of TC R17 mainly by increasing or reducing surface total precipitation, warm temperature anomaly, upward vertical velocity and inward radial wind within the TC circulation.