气候与下垫面变化对新安江上游(屯溪站)径流变化贡献率的定量分析*
Quantitative evaluation of contributions of climate change and underlying surface change to the runoff at the upper catchment of Xin'anjiang (Tunxi Hydrological Station)
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摘要: 采用Mann-Kendall 统计检验、Pettitt检验、弹性系数法对1955—2013 年新安江上游屯溪水文站(以下简称“屯溪站”)的年平均径流量变化进行了分析,发现该站年平均径流量在1968年出现突变点,整个时段内没有明显的单调性变化趋势.在1968年后,屯溪站多年平均径流量总体增加了约19%,其中气候变化导致该时段内径流量的增加量约为30%,其中包括降雨量增加对径流增加的贡献约19%和蒸发量减少对径流增加的贡献量约11%,而下垫面变化(主要为土地利用变化)则导致1968年后屯溪站多年平均径流减少约11%.因此,气候变化(降雨增加和蒸发减少)是1968年后屯溪站多年平均径流量显著增加的主要原因,而下垫面的变化则导致了该站多年平均径流量的减少.Abstract: Tunxi Hydrological Station (THS) is located at the upper catchment of Xin'anjiang.The time-serial runoff data during 1955—2013 at THS were analyzed based on Mann-Kendall test,Pettitt test and elastic coefficient methods.The results show there is no significant increase/decrease trend,while the abrupt change point of runoff was found in 1968.The Annual Mean Runoff (AMR) at THS has increased by 19% after 1968 with the fractional contribution of climate change to AMR increase by 30% and the fractional contribution of underlying surface change to AMR decrease by 11%.The increased precipitation has contributed to AMR increase by 19% while the decreased evaporation has contributed to AMR increase by 11%.Therefore climate change has been the main factor leading to AMR increase at THS after 1968 while the underlying surface change has slightly contributed to AMR decrease at this station.
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