Projection of temperature and precipitation under SSPs-RCPs Scenarios over northwest China

Climate change significantly affects the environmental and socioeconomic conditions in northwest China.Here we evaluate the ability of five general circulation models(GCMs)from 6th phase of the Coupled Model Inter-comparison Project(CMIP6)to reproduce regional temperature and precipitation over northwest China from 1961 to 2014,and project the future temperature and precipitation during 2021 to 2100 under SSPs-RCPs(SSP1-1.9,SSP1-2.6,SSP2-4.5,SSP3-7.0,SSP4-3.4,SSP4-6.0 and SSP5-8.5).The results show that the CMIP6 models can simulate temperature better than precipitation.Projections show that the annual mean temperature will further increase under different SSPs-RCPs scenarios in the 21st century.Future climate changes in the near-term(2021-2040),mid-term(2041-2060)and long-term(2081-2100)are analyzed relative to the reference period(1995-2014).In the long term,warming will be significantly higher than the near and mid-terms.In the long term,annual mean temperature will increase by 1.4℃,1.9℃,3.3℃,5.5℃,2.7℃,3.8℃ and 6.0℃ under SSP1-1.9,SSP1-2.6,SSP2-4.5,SSP3-7.0,SSP4-3.4,SSP4-6.0 and SSP5-8.5,respectively.Spatially,warming in the Junggar Basin will be higher than those in the Tarim Basin.Seasonally,the maximum warming zone will be in the mountainous areas of Tarim Basin during spring and autumn,in the southern basin during winter,and in the east during summer.Precipitation shows an increasing trend under different SSPs-RCPs in the 21st century.In the long term,increase in precipitation will be significantly higher than in the near and mid-terms.Increase in annual precipitation in the long term will be 4.1% under SSP1-1.9,13.9% under SSP1-2.6,28.4% under SSP2-4.5, 35.2% under SSP3-7.0, 6.9% under SSP4-3.4, 8.9% under SSP4-6.0, and 27.3% under SSP5-8.5 relative to the reference period of 1995-2014. Spatially, precipitation increase will be higher in the south than the north, especially higher in mountainous regions than the basin under SSP2-4.5, SSP3-7.0, and SSP5-8.5. Seasonally, highest increase can be expected for winter, followed by spring, with significant increase in mountainous regions of southern Tarim Basin. Summer precipitation will reduce in Tian Shan and basins but will significantly increase in the northern margin of the Kunlun Mountain.