The Role of Soil Moisture Feedbacks in Future Summer Temperature Change over East Asia

The increased mean temperature and temperature variability under global warming can have many adverse impacts on human and natural systems. However, how soil moisture-atmosphere interaction can affect future climate change over East Asia remains largely unclear. We use long-term regional climate simulations with the Community Climate System Model-Weather Research and Forecasting (CCSM-WRF) model system to investigate the role of soil moisture feedbacks in future summer surface air temperature change over East Asia. Results show that summer surface air temperature and precipitation are projected to increase over most of East Asia by the end of 21st century under the Representative Concentration Pathway 8.5 (RCP8.5) scenario. Soil moisture feedbacks lead to an increased summer mean temperature of 0.15 degrees C averaged over East Asia, with key regions appearing over the northern part of Tibetan Plateau, Sichuan Basin, and the middle and lower reaches of the Yangtze River Basin during 2071-2100 under the RCP8.5 scenario. And regionally averaged interannual temperature variability induced by soil moisture feedbacks is substantially enhanced as a whole. Regarding the spatial distribution, soil moisture feedbacks on interannual temperature variability are projected to strengthen notably over the northern part of Tibetan Plateau, the Hexi Corridor, and Sichuan Basin and weaken over the south Tibetan Plateau, southeast China, and the areas surrounding the Lake Baikal. The stronger responses of surface heat and the atmospheric boundary layer to dry anomalies than wet anomalies lead to an obvious dry-wet asymmetry of soil moisture feedbacks on summer surface air temperature over the key areas of East Asia.