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. 相似文献
During the Maduo Earthquake (MDEq) (Mw 7.3), which occurred on 22 May 2021 in the northern Tibetan Plateau, coseismic surface ruptures, numerous land liquefaction instances and landslides, were triggered along the NW strike of the?~?160 km long aftershock zone. We performed three times emergency field surveys (22 May to 3 Jun., 28 Jun. to 14 Jul., 8–24 Oct., 2021) with unmanned aerial vehicle (UAV) orthophoto and digital elevation model (DEM) data. We found a discontinuous coseismic surface rupture zone along with loose sediment, severe sand liquefaction regions with an area of?~?103 km2 along the Yellow River and its tributaries. More than 23 coseismic landslides had been checked with relative small-size volume for limited local terrain relief. Three of those landslides had relatively small source areas and volumes and affected relatively large areas. We identified numerous tension cracks in and around the trailing edges, which could trigger more landslides in the future. Further detailed research into the occurrence of these three landslides will reveal the failure mechanism of the earthquake (shaking)–freeze–thaw effect–rainfall disaster chain. Here, we present basic information to aid the overall understanding of the preliminary characteristics of coseismic earthquake-triggered landslides, sand liquefaction, and possible follow-up disasters.
Landslides - On July 10, 2020, a catastrophic landslide with a slope angle of only 8° occurred in the red-bed series strata in Qianxi, Guizhou, southwestern China, due to prolonged rainfall,... 相似文献