Hydrological effects of climate variability and vegetation dynamics on annual fluvial water balance in global large river basins
Hydrological effects of climate variability and vegetation dynamics on annual fluvial water balance in global large river basins
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DOI：
10.5194/hess-22-4047-2018
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发表时间：
2018-07
影响因子：
6.3
通讯作者：
Jianyu Liu;Qiang Zhang;V. Singh;Changqing Song;Yongqiang Zhang;P. Sun;Xihui Gu
中科院分区：
文献类型：
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作者：
Jianyu Liu;Qiang Zhang;V. Singh;Changqing Song;Yongqiang Zhang;P. Sun;Xihui Gu
摘要。降水划分为径流(R)和蒸散发(E)，由Budyko框架中的控制参数（即Choudhury和Yang方程中的n参数）控制，对于评估全球尺度上的水平衡至关重要。人们普遍认为这一控制参数的空间变化受景观特征的影响，但其时间变化特征尚不明确。考虑有效降水量（Pe），将Budyko框架扩展到年水平衡分析。为了反映供水（降水，P）和能量（潜在蒸散发，E0）之间的不匹配，我们提出了一个气候季节性和非同步指数（SAI），包括P和E0之间的相位和振幅不匹配。以26个大型河流流域的流量变化为例，发现SAI是解释参数n年方差的51%的关键因子，植被动态(M)显著影响n的时间变化，解释了67%的方差。利用SAI和M，在年尺度上建立了参数n的半经验公式来描述年径流量(R)和蒸散量(E)。然后量化气候变率（Pe、E0和SAI）和M对R和E变化的影响。结果表明，全球大部分流域的R和E变化主要受Pe变化的控制，而东亚副热带季风区的SAI是R和E变化的控制因子。SAI、M和E0对E的影响大于对R的影响，Pe对R的影响更大。
Abstract. The partitioning of precipitation into runoff (R) and evapotranspiration (E), governed by the controlling parameter in the Budyko framework (i.e., n parameter in the Choudhury and Yang equation), is critical to assessing the water balance at global scale. It is widely acknowledged that the spatial variation in this controlling parameter is affected by landscape characteristics, but characterizing its temporal variation remains yet to be done. Considering effective precipitation (Pe), the Budyko framework was extended to the annual water balance analysis. To reflect the mismatch between water supply (precipitation, P) and energy (potential evapotranspiration, E0), we proposed a climate seasonality and asynchrony index (SAI) in terms of both phase and amplitude mismatch between P and E0. Considering streamflow changes in 26 large river basins as a case study, SAI was found to the key factor explaining 51 % of the annual variance of parameter n. Furthermore, the vegetation dynamics (M) remarkably impacted the temporal variation in n, explaining 67 % of the variance. With SAI and M, a semi-empirical formula for parameter n was developed at the annual scale to describe annual runoff (R) and evapotranspiration (E). The impacts of climate variability (Pe, E0 and SAI) and M on R and E changes were then quantified. Results showed that R and E changes were controlled mainly by the Pe variations in most river basins over the globe, while SAI acted as the controlling factor modifying R and E changes in the East Asian subtropical monsoon zone. SAI, M and E0 have larger impacts on E than on R, whereas Pe has larger impacts on R.