Contribution of multiple climatic variables and human activities to streamflow changes across China

Abstract

Using monthly streamflow data from the 1960-2000 period and annual 16 streamflow data from the 2001-2014 period, and also meteorological data from the 17 1960-2014 period from 815 meteorological stations across China, the Budyko-based 18 hydrothermal balance model was used to quantitatively evaluate the fractional 19 contributions of climate change and human activities to streamflow changes in ten 20 river basins across China. Particular importance was attached to human activities, 21 such as population density and Gross Domestic Product (GDP), and also water 22 reservoirs in terms of their relationship with streamflow changes. Results indicated 23 that: (1) streamflow changes of river basins in northern China were more sensitive to 24 3 climate change than those of river basins in southern China. Based on the degree of 25 sensitivity, the influencing factors to which streamflow changes are sensitive included: 26 precipitation > human activities > relative humidity > solar radiation > maximum 27 temperature > wind speed > minimum temperature. Hence, it can be argued that 28 hydrological systems in northern China are more fragile and more sensitive to 29 changing environment than those in southern China and hence water resources 30 management in northern China is more challenging; (2) during 1980-2000, climate 31 change tended to increase streamflow changes across China and have a dominant role 32 in streamflow variation. However, climate change tends to decrease streamflow in 33 river basins of northern China. Generally, human activities cause a decrease of 34 streamflow across China; (3) In recent years such as a period of 2001-2014, human 35 activities tend to have increasing or enhancing impacts on instream flow changes, and 36 fractional contributions of climate change and human activities to streamflow changes 37 are, respectively, 53.5% and 46.5%. Increasing human-induced impacts on 38 streamflow changes have the potential to add more uncertainty in the management of 39 water resources at different spatial and temporal scales.40 41

Spatial-temporal changes in river runoff and terrestrial ecosystem water retention under 1.5 °C and 2 °C warming scenarios across China

“…10). This finding is supported by some previous studies (Dan et al, 10 2012;Wang et al, 2016;Huang et al, 2016;Liu et al, 2017b). The correlations were smaller in the Yellow River basin, Hai River basin, and Huai River basin than other basins, even less than 0.5 for some grids in the Northwest River basins and the source regions of the Yellow River basin (Fig.…”

“…There are ten main basins in China (Fig.1), including the Songhua River basin (SHR), Liao River basin (LR), Northwest River basins (NWR), Hai River basin (HR), and Yellow River basin (YR) in the northern China; the Yangtze River basin 10 (YTR), Huai River basin (HuR), Southeast River basins (SER), Southwest River basins (SWR), and Pearl River basin (PR) in the southern China (Leng et al, 2015;Liu et al, 2017b). The temperature increases from north to south, and precipitation increases gradually from northwest to southeast (Xie et al, 2007).…”

“…Therefore, this study applied ensemble projections using multiple climate scenarios by multiple GCMs to provide a more comprehensive and robust results. Human activities also have unavoidable impacts on water resources, more and more evidence showed that the influence of human activities on water resources is significantly enhanced Yuan et al, 2016;Liu et al, 2017b;Zhai and Tao, 2017). Human activities such as land use/cover changes and the increase in water withdrawal will affect river runoff in the future, which is 15 not taken into account in this study.…”

Decreased Streamflow in the Yellow River Basin, China: Climate Change or Human‐Induced?

“…Then, the impact of climatic variables and underlying surface on streamflow can be evaluated by [25]:…”

Global Attribution of Runoff Variance Across Multiple Timescales

“…However, it fails to consider the effects of other factors (e.g., climate seasonality, land cover, and human impact). Other factors have remarkable and significant impacts on regional and global hydrological cycles (Gudmundsson et al, ; Liu et al, ; Yang et al, ; Yao et al, ). Meanwhile, Zhang et al (2016a) pointed out that more attention should be paid to the other factors (e.g., human impacts) with respect to their impacts on the R and E variances.…”