A Numerical Simulation Study of Impacts of Historical Land-Use Changes on the Regional Climate in China Since 1700

By using the improved regional climate model (BCC_RegCM1.0), a series of modeling experiments are undertaken to investigate the impacts of historical land-use changes (LUCs) on the regional climate in China.Simulations are conducted for 2 years using estimated land-use for 1700, 1800, 1900, 1950, and 1990.The conversion of land cover in these periods was extensive over China, where large areas were altered from forests to either grass or crops,or from grasslands to crops. Results show that, since 1700 , historical LUCs have signi cant effects on regional climate change,with rainfall increasing in the middle and lower reaches of the Yangtze River Basin, Northwest China, and Northeast China, but decreasing by different degrees in other regions. The air temperature shows significant warming over large areas in recent hundred years,especially from 1950 to 1990, which is consistent with the warming caused by increasing greenhouse gases.On the other hand, historical LUCs have obvious effects on mean circulation, with the East Asian winter and summer monsoonal ows becoming more intensive, which is mainly attributed to the amplified temperature difference between ocean and land due to vegetation change.Thus,it would be given more attention to the impacts of LUCs on regional climate change.