基于水分—能量分配框架的径流变异分解方法

An attribution approach of streamflow variations based on the water-energy partitioning framework

在气候变化和人类活动扰动下,河川径流变异对气候和下垫面因素的响应机制及其变异的定量归因一直是水文学研究的重点和难点。本文基于平面几何方法及水分—能量分配框架,构建量化气候与下垫面因素对径流变异贡献程度的解析公式。利用全球83个典型流域的长序列数据集,将水分—能量分配框架与Budyko分解法进行对比。结果表明,水分—能量分配框架和Budyko分解法的全球径流归因结果较为一致,证实了其有效性,且相对Budyko推导过程更加简单,可操作性更强。此外,本文进一步发现在大部分流域中,径流由气候变化引起的正向效应(导致径流增加)被下垫面因素引起的负向效应(径流减少)抵消,即存在补偿效应,且该补偿效应随着干旱程度的增加而减弱。本文提出新的流域径流变异分解方法,为深入理解全球径流变化成因提供新的研究思路。

In the context of climate change and anthropogenic disturbances,understanding the response mechanisms of streamflow variations to changes in climate and watershed underlying characteristics has been a vital research focus in hydrology.Based on planar geometry and the water-energy partitioning framework,this study proposed the quantitative analytical formulas for attributing the contributions of climate and underlying characteristics to streamflow variations.Using long-term datasets of 83 typical watersheds in the world,the attribution results calculated by the water-energy partitioning framework and the Budyko decomposition method were compared.The results show that the global streamflow attributions of these two approaches were generally consistent,affirming the effectiveness of the newly developed framework.Furthermore,the water-energy partitioning framework is much simpler and easier to be applied,as compared to the Budyko decomposition method.It is also found that in most basins,the positive impacts of climate change on streamflow(resulting in increased streamflow)were offset by the negative effect caused by underlying characteristics(resulting in decreased streamflow),indicating a potential compensatory effect,while such a compensatory effect weakens with increasing drought severity.This study proposes a new decomposition method to streamflow attribution analysis,and also provides new perspectives for understanding the causes of global streamflow changes.