Projection of future changes in climate in Northeast China using a CMIP5 multi-model ensemble

Based on observational data of CN05 and the outputs of 26 CMIP5 (Coupled Model Inter-comparison Project Phase 5) models adopted in the Fifth Assessment of the Intergovernmental Panel on Climate Change (IPCC AR5), the abilities of the 26 CMIP5 models to simulate surface air temperature and precipitation of the three provinces in Northeast China during 1961-2005 were assessed. Four best-fit models were selected by Taylor Diagram out of the 26 CMIP5 models, and simulations of future changes in climate and associated uncertainties under different representative concentration pathways (RCPs) by the multi-model ensemble mean (MME) of the four models were examined. The MME of the four best-fit CMIP5 models has higher credibility to simulate the climate change in Northeast China, especially for surface air temperature. Based on estimates of water deficit, future climatological drought in Northeast China was analyzed under RCP4.5 and RCP8.5 over three time periods (i.e. 2016-2035, 2046-2065, and 2080-2099). Based on simulations of the MME of the four best-fit CMIP5 models, an ongoing warming is predicted under different RCPs in Northeast China from 2006 to 2099, especially under RCP8.5 (0.53 degrees C/10a), which is twice that under RCP4.5 (0.22 degrees C/10a). By the end of the 21st century (2080-2099), changes in surface air temperature tend to stabilize under RCP4.5 while continuously increasing under RCP8.5. Spatially, the northern part of Northeast China generally shows greater and more rapid warming than the southern part, and the inland areas show weaker and slower warming than the coastal areas in Liaoning province. In future, the annual mean precipitation is predicted to increase but with great fluctuations. The increasing tendency from 2006 to 2099 is 1.10%/10a under RCP4.5 and 1.48%/10a under RCP8.5, respectively. By the end of the 21st century (2080-2099), the annual mean precipitation is predicted to increase by 11.24 +/- 7.77% under RCP4.5 and 15.95 +/- 7.72% under RCP8.5, respectively relative to the period 1986-2005. Spatially, future change in precipitation over most parts of Northeast China is predicted to intensify, with the western part of Liaoning province changing the most. Based on the analysis of water deficit, most parts of Northeast China are projected to become wetter in the mid-tern and later period of the 21th century under RCP4.5, while the eastern part would become wetter and the western part would become drier under RCP8.5, relative to the period 1986-2005.