Typhoon statistics in variable resolution Asia-Pacific CAM-SE

Abstract. Three Asia-centric configurations of the Community Atmosphere Model with the Spectral Element dynamical core (CAM-SE) were set up, with horizontal resolutions of approximately 1° globally, 1° increasing to 0.5° over the Asia-Pacific, and 1° increasing to 0.25°. A typhoon tracking algorithm was developed to extract the tracks of typhoons generated by the simulations. The typhoon intensities were bias corrected using scale conversion factors calculated from a comparison of tracks extracted from the European Centre for Medium-Range Weather Forecasts Reanalysis version 5 (ERA5) and the International Best Track Archive for Climate Stewardship (IBTrACS). Typhoon frequency, track density, genesis locations, and energy were calculated from 20 years of equilibrium climate simulations using the three configurations, then compared with the statistics from ERA5 and IBTrACS. The 1° and 0.5° CAM-SE simulations were unable to produce enough “Super Typhoons” (maximum sustained central wind speed ⩾ 51 m s^-1) even after bias correction. The 0.25° simulation managed to produce enough “Super Typhoons”, indicating that at least 0.25° horizontal resolution is advisable for global climate simulations to produce appropriate “Super Typhoon” statistics. The regionally refined 0.25° CAM-SE configuration was estimated to be at least two times faster than a globally 0.25° typical configuration.