Effect of Model Resolution on Tropical Cyclone Climate Projections

The effect of model resolution on projected climatological features of tropical cyclones (TCs) was investigated via 25-year present-day and future global warming projections using the Japan Meteorological Agency/Meteorological Research Institute Atmospheric General Circulation Model with four resolutions ranging from TL95 (180-km mesh) to TL959 (20-km mesh). The finest resolution (TL959) showed the highest skills in terms of TC intensity and interannual and seasonal variations in TC genesis number. Resolutions of TL319 (60-km mesh) and finer showed a significant future increase in the frequency of intense TCs, whereas resolutions coarser than TL319 showed no such change, indicating that TL319 is the critical resolution in projecting future change in the frequency of intense TCs. Overall, high model resolution is preferable for realistic and reliable climate projections. Resolutions of TL159 (120-km mesh) and finer showed similar skills, biases, and future changes in the spatial pattern of TC genesis frequency (TGF) and TC genesis number, indicating the potential use of lower model resolutions for minimizing uncertainties in future changes in the mean state of TGF and TC genesis number.