Evaluation of climatological tropical cyclone activity over the western North Pacific in the CORDEX-East Asia multi-RCM simulations

The ability of five regional climate models (RCMs), within the Coordinated Regional Climate Downscaling Experiment (CORDEX) for East Asia, to simulate tropical cyclone (TC) activity over the western North Pacific is evaluated. All RCMs are performed at similar to 50 km resolution over the CORDEX-East Asia domain, and are driven by the ECMWF Interim Re-Analysis (ERA-Interim) for the period 1989-2008. ERA-Interim sea surface temperature is prescribed as the lower boundary. Performances of the individual RCMs and multi-RCM ensemble mean are investigated in detail for 20-year climatology, intensity, and interannual variability of TC activity compared to observational datasets. Although most of the individual RCMs show significant biases and underestimate TC intensity due to horizontal resolutions still too low to resolve the most intense observed TCs, they reasonably capture the observed climatological spatial distribution and interannual variability of TC activity. The multi-RCM ensemble mean based on the model performance generally outperforms most of the individual models with smaller biases and higher correlation on the spatial and temporal variation of TC activity. This ensemble mean reduces the uncertainty in the simulated TC activity by a single RCM. These analyses suggest that the multi-RCM ensemble within CORDEX-East Asia can be applied to provide more reliable and credible estimation of future TC activity over the western North Pacific due to climate change.