Zhang L, Nan Z, Wang W, Ren D, Zhao Y, Wu X. Separating climate change and human contributions to variations in streamflow and its components using eight time-trend methods. Hydrological Processes. 2018, Online. DOI:10.1002/hyp.13331.
Abstract: Separating impacts of human activities and climate change on hydrology is essential for watershed and ecosystem management. Many previous studies have focused on
the impacts on total streamflow, however, with little attentions paid to its components(i.e., baseflow and surface run‐off). This study distinguished the contributions of climate change and human activities to the variations in streamflow, baseflow,
and surface run‐off in the upstream area of the Heihe River Basin, a typical inland river basin in northwest China, by using eight different forms of time‐trend methods. The isolated contributions to streamflow variation were also compared with those obtained by two Budyko‐based approaches. Our results showed that the time‐trend
methods consistently estimated positive contributions of climate variability and
human activities to the increases in streamflow and its components but with obviously varying magnitudes. With regard to streamflow, the time‐trend method
double‐mass‐curve–Wei, with a physical basis, produced a reasonable smaller contribution
of human activities than climate changes, inconsistent with the Budyko‐based
approaches. However, all the other time‐trend methods led to contrary results. The
contributions to baseflow variation diverged more significantly than those to
streamflow and surface run‐off, ranging from 24% to 92% for human activities and from 8% to 76% for climate variability. In terms of surface run‐off, most of the
time‐trend approaches produced smaller contributions of human activities (ranging
from 21% to 49%) than climate change. The uncertainties associated with the various time‐trend approaches and the baseflow separation algorithm were revealed and discussed, along with some recommendations for future work.