气候变化对不同气候区流域年径流影响的识别

气候变化对流域径流的影响显著,但不同流域径流对各气候因子敏感性不同,具有明显的空间分异性。本文以位于半湿润、湿润地区的松花江、子牙河以及西苕溪流域为例,基于Budyko 水热平衡经验模型,采用归因分析方法分离了气象要素趋势性变化对年径流和潜在蒸发变化率的贡献与差异性。结果表明:1960-2008年,在上述3个流域中,降水趋势性变化对年径流变化的贡献比潜在蒸发大。松花江和子牙河流域各气象要素趋势性变化对潜在蒸发变化率的贡献排序为:温度>风速>水汽压>日照时数,而西苕溪流域为:温度>日照时数>风速>水汽压。在气候要素共同作用下,松花江和子牙河流域平均年径流分别以0.48和1.51 mm a^-2的速率减少,而西苕溪流域年径流则以1.42 mm a^-2的速率增加。所得结果加深了气候变化对径流影响机制和程度的认识,可作为流域水资源适应性管理的科学依据。

Identification of impact of climate change on annual runoff in typical basins of different climate zones

Influences of climate factors on runoff are obvious, while the sensitivities of runoff to climate factors show significant variability in spatial distribution. In this paper, three basins are chosen including Songhua River Basin (SRB), Ziya River Basin (ZRB) and Xitiao River Catchment (XRC) which are located in semi-humid and humid area. In these basins, annual runoff is simulated with a Budyko-type equation, and contribution of each climate factor to runoff and potential evapotranspiration change is separated by Attribution Analysis, and finally, the differences among typical basins are evaluated. It showed that precipitation change contributed more than potential evapotranspiration to runoff change during 1960-2008. Moreover, contribution of climate factors to potential evapotranspiration ranked as temperature (T)>wind speed (U)>vapor pressure (e_a)>sunshine duration (S) in SRB and ZRB, and T>S>U>e_a in XRC. Due to the integrated action of climate factors, annual runoff decreased with the change rate of -0.48 mm a^-2 and -1.51 mm a^-2 in SRB and ZRB respectively, and it increased with change rate of 1.42 mm a^-2 in XRC. This paper can not only deepen the understanding of the mechanism how the climate change affect runoff, and also provide the scientific basis for water resources management in basins'scale under the changing climate.