Response of Intensity and Structure of Typhoon Jebi (2018) before Landfall to 2-K and 4-K Warmed Future Climates in Dynamical Downscaling Experiments

Abstract

To investigate the effects of global warming on Typhoon Jebi (2018), we performed high-resolution pseudoglobal 2-K and 4-K warming simulations with initial time ensembles using a regional atmospheric model. The pseudoglobal warming experiments demonstrated the further facilitation of Jebi’s development with a higher rise in the temperature. The intensity over the ocean to the south of Japan increased by 8% (20%) in the climate warmed 2-K (4-K) to the current climate. Typhoon Jebi, in the 4-K warming simulations, maintained a robust inner-core characterized by a compact and deep eyewall and well-developed primary and secondary circulations even immediately before landfall, in contrast to the result in the 2-K warming simulations. The sustained robust axisymmetric structure immediately before landfall in the 4-K warming runs was strongly associated with the enhanced ocean warming around Japan, notable moistening of the lower-to-middle troposphere in the vicinity of Typhoon Jebi, and a significant decrease in vertical wind shear under the extremely warmed future climate. The nonlinear responses of Typhoon Jebi to the tropospheric temperature rise are attributable to the drastic changes in the midlatitude’s thermodynamic and dynamic environments under climate changes resulting from 2-K to 4-K global warming.