热带气旋的移动速度对其尺度的影响OA

Tropical cyclones(TCs),as intense weather systems,exert destructive impacts that depend not only on their intensity but also closely on their size.However,the relationship between TC translation speed and its size remains insufficiently understood.Based on the Extended Best Track(EBT)dataset and ERA5 reanalysis data from 1988 to 2021 in the North Atlantic,this study investigates the statistical relationship between TC translation speed and two size metrics and its possible physical mechanisms:the radius of maximum wind(RMW)and the radius of 17 m·s-1 wind(R17).Results show that R17 increases significantly with the translation speed,with its higher percentiles being more sensitive to changes in moving speed.RMW also increases slightly with the translation speed,and its change can largely be explained by that of R17.Physically,faster-moving TCs significantly weaken sea surface temperature(SST)cooling,thereby maintaining or enhancing surface enthalpy fluxes and increasing atmospheric instability.Concurrently,faster-moving TCs substantially intensify low-level convergence in the forward quadrant.The combined effect of thermal and dynamical processes jointly intensifies the upward motion,thereby facilitating the development of spiral rainbands,whose resultant diabatic heating further enhances the inward transport of angular momentum.This process results in the expansion of the outer wind field,causing an increase in R17,which consequently enlarges RMW.