资源环境科技发展态势分析平台

Land use and land cover change (LUCC) is an important external forcing agent of climate change. The comparison of current (2000 A.D.) with historical (1850 A.D.) land cover maps suggests that most of the Eurasian continent has experienced robust and significant LUCC during the past century, especially evident transition from forests to croplands. Therefore, two experiments (control and sensitivity experiments with current and historical land cover maps, respectively) are conducted by using the Community Atmosphere Model Version 5.0 (CAM5.0) coupled with the Community Land Model Version 4.0 (CLM4.0) to investigate the potential effects of LUCC on temperature extremes over Eurasia. Results show significant increases (e.g., 0.2-0.7 degrees C) in extreme cold indices (e.g., TNn) over central and eastern China, India and mainland Southeast Asia in response to such robust LUCC. Broad and significant decreases (e.g., approximately -1 degrees C) in extreme warm indices (TXx) are mainly observed in Eastern Europe and western Siberia. Moreover, the effects of LUCC on high and low-percentile extreme indices of minimum temperature (T-min) are generally symmetrical, but those for maximum temperature (T-max) indices are asymmetrical, which are characterized by stronger influences on high-percentile indices rather than low ones. Further analyses suggest that LUCC-induced changes in temperature extremes are mostly influenced by shifts in the mean state of T-min/T-max. Furthermore, the responses and sensitivities of T-min/T-max to LUCC are remarkably distinct among regions. This result mainly occurs because of different LUCC-induced changes in surface energy components, which depend on the region-specific climatology of each energy component and the dominant plant functional types.