气候变化对无定河流域生态水文过程的影响

Climate change impacts on the ecohydrological processes in the Wuding River basin

建立分布式生态水文过程模式,模拟分析了黄土高原无定河流域近40a来及未来气候变化情景下水循环和植被生产力的演变特征。结果显示,无定河流域近40a来温度上升,而降水量没有明显的下降趋势,但年际波动幅度变小。与之相应,地表蒸散量也没有明显的变化趋势。然而,因大气CO2浓度的上升,植被净生产力明显增加,速率约为0.6gCm-2a-1,水分利用效率随之提高。该流域生态系统对HadCM3气候变化情景的响应显著,蒸散、地表径流和植被净第一性生产力(NPP)均增加,植被水分利用效率明显提高。

A distributed eco-hydrological process-based model was developed to simulate the water budget and vegetation productivity in the Wuding River basin, Loess Plateau, under the scenarios of historical and future climate. Since the mid of last century, the annual mean of air temperature tended to increase and precipitation appeared no tendency, but with a lower amplitude of annual variation in the basin. Correspondently, the actual evapotranspiration had similar tendency with precipitation. However, the vegetation net primary productivity （NPP） increased with a rate of 0.6 gC m^-2 a ^-1, and water use efficiency increases due to fertilization of air CO2 enrichment. Under the HadCM3 climate scenario in the 21st century, the simulated results show that the actual evapotranspiration, surface runoff, vegetation NPP and water use efficiency will increase significantly.