Multimodel GCM-RCM ensemble-based projections of tropical cyclone activities over CORDEX East Asia domain

Abstract

In this study, we investigated the future changes in tropical cyclone (TC) activities using regional climate models (RCMs) forced by multi-global climate models (GCMs). The simulation experiments were conducted at a 25-km horizontal resolution over the Coordinated Regional Climate Downscaling Experiment (CORDEX)-East Asia (EA) domain. The ensemble mean method was applied to reduce the uncertainty of each single RCM. During the historical period (1981-2005), the ensemble mean of RCMs captured TC frequency comparable to observation data but simulated their intensity weakly. When comparing the near future (2026-2050) and far future (2076-2100) periods under the high emission scenario to the historical period, the RCMs exhibited a consistent feature: the core region of TC genesis migrated northward. As the genesis region shifted, the TC activities also moved northward to the mid-latitude. In addition, the extreme intensity of landfalling TCs had increased above 25 degrees N compared to the historical period. These results are related to environmental fields; increasing relative vorticity and specific humidity of 850 hPa and weakening of vertical wind shear over the mid-latitude due to higher sea surface temperature compared to the historical period.