High-resolution Regional Climate Model Projections Of Wet And Dry Changes In China

Climate models are widely used in the simulation and prediction of climate change at present.As one of the important tools to research climate change,the horizontal resolution of global climate model too low to satisfy the needs of regional scale climate change research.The dynamic scaling of global climate model by high-resolution regional climate model can effectively improve the accuracy of regional climate simulation and prediction,especially in China which with the complex terrain.We evaluate the ability of models to simulate variables affected the change of dry/wet in China and aridity index(AI).Than we project the future dry/wet climate changes in China under the Representative Concentration Pathway(RCP)4.5 scenario using experimental data of a high-resolution regional climate model(Reg CM4)nested within three global climate models and analyze the main reasons to effect the future dry/wet change.For the reference period of 1986–2005,Reg CM4 is capable of simulating the spatial pattern of variables affected the change of dry/wet and AI in China reasonably and partly corrected the simulation bias of global climate models.Based on the projections of Reg CM4,the AI averaged over China would decrease by 2–4% and 2–5%in the middle(2046–2065)and end(2081–2098)of the 21 st century relative to the reference period,respectively,with central Northwest China becoming wetter while other regions drier.The change tendency is not rely on the choice of calculation methods of potential evapotranspiration.The predominant factor for the future dry/wet climate changes in China varies with regions.Precipitation is the first leading factor in central Northwest China,while potential evapotranspiration changes due to increasing temperature play the major role in the rest regions.In all,potential evapotranspiration has a bigger effect on future dry/wet change than precipitation.