Extreme weather events over China: assessment of COSMO-CLM simulations and future scenarios

Extreme climate events over a wide Chinese area are investigated with the regional climate model COSMO-CLM at high resolution (0.125 degrees) through the use of some extreme indicators. Two hindcast simulations, driven respectively by ERA-Interim reanalysis and the global model CMCC-CM over the period 1979-2011 have been analysed in order to check the model's ability to represent a subset of climate indicators for precipitation and temperature, as a preliminary step to assess changes regarding extreme weather events expected under greenhouse gas concentration variations. The effort to increase resolution in a regional model has interesting benefits in representing extreme indices, especially in complex orography areas. Results show that the model provides a good representation of the spatial climatology of the indices considered, with high correlation values between the model and observations. Future climate changes concerning extreme events have been investigated, employing the IPCC RCP4.5 and RCP8.5 scenarios. Projections reveal that temperature indicators are characterized by positive trend values, highlighting an increase in minimum and maximum temperatures over the period 2041-2070, especially over southeast China. Extreme precipitation events are generally projected to increase over the whole region considered, especially under RCP8.5 scenario.