Modeled responses of summer climate to realistic land use/cover changes from the 1980s to the 2000s over eastern China

摘要

Eastern China has experienced substantial agricultural expansion and deforestation in recent decades. We modeled the influence of land use/cover changes (LUCCs) over eastern China on the regional climate using the Weather Research and Forecasting model with the Noah-multiparameterization land surface scheme. Two 21 year (1980-2000) experiments were performed using the same settings, except for the land use/cover data for the 1980s and the 2000s. The results showed that in northern China, decreases in the surface air temperature of approximately 0.3-0.5 degrees C and decreases (increases) in rainfall over the lower reaches of the Yangtze River valley (southern China, northeastern China, and the Korean Peninsula) of approximately 3% (6-7%) in the summer were associated with LUCCs in eastern China from the 1980s to the 2000s. The cooling effect in northern China, which was primarily attributable to an increase in the surface latent heat flux of approximately 7.3-9.6Wm(-2), weakened the land-ocean thermal contrast, suggesting the presence of a weaker summer monsoon over eastern China. As a result, rainfall over the lower reaches of the Yangtze River valley (southern China) tended to decrease (increase). In addition, the cooling effect may have produced an anomalous cyclonic circulation from the surface to the midtroposphere over northeastern China and the Korean Peninsula, resulting in increased rainfall over this area. Key Points