8.5.4 Summary

Because most AOGCMs have coarse resolution and large-scale systematic errors, and extreme events tend to be short lived and have smaller spatial scales, it is somewhat surprising how well the models simulate the statistics of extreme events in the current climate, including the trends during the 20th century (see Chapter 9 for more detail). This is especially true for the temperature extremes, but intensity, frequency and distribution of extreme precipitation are less well simulated. The higher-resolution models used for projections of tropical cyclone changes (Chapter 10) produce generally good simulation of the frequency and distribution of tropical cyclones, but less good simulation of their intensity. Improvements in the simulation of the intensity of precipitation and tropical cyclones with increases in the resolution of AGCMs (Oouchi et al., 2006) suggest that when climate models have sufficient resolution to explicitly resolve at least the large convective systems without using parametrizations for deep convection, it is likely that simulation of precipitation and intensity of tropical cyclones will improve.