Future Climate Projection in Northwest China With RegCM4.6

Abstract An effective assessment of future climate change, especially future precipitation forecasting, is an important basis for the rational development of adaptive strategies for Northwest China, where the ecological environment is fragile and encompasses arid and semiarid regions. In this work, the performance of a regional climate model is assessed; then, climate changes in the near future (2018–2037), middle future (2050–2069), and distant future (2080–2099) are analyzed under representative concentration pathways (RCPs) RCP2.6, RCP4.5, and RCP8.5. The following conclusions are drawn: (1) Compared to the Met Office Hadley Centre Earth System (HadGEM2‐ES) global climate model, the latest regional climate model, RegCM4.6, with a community land model land surface process scheme and Tiedtke cumulus convective parameterization, can create a good simulation of the present‐day mean climatology over Northwest China, including temperature, precipitation, and climate extremes, and can also provide finer‐scale climate information in complex terrain and better correct the cold bias than HadGEM2‐ES. At the same time, RegCM4 inherited the bias from HadGEM2‐ES, for example, both the RegCM4 and the HadGEM2‐ES overestimated precipitation in DJF in the southeast of the study area. (2) The future near surface air temperature will experience continuous warming over Northwest China under the RCP8.5 scenario, and the warming will become more significant and exceed 6 °C by the end of the 21st century. In RegCM4, future precipitation will continue to increase and will increase by 50 mm by the end of the 21st century relative to historical data. The extreme climate index summer days will continue to increase, indicating that high temperatures will be more frequent in Northwest China. In contrast, the consecutive dry days will decrease, likely because of the increase in precipitation.