Predicting long-term hydrological change caused by climate shifting in the 21st Century in the headwater area of the Yellow River Basin

Abstract

The Qinghai-Tibetan Plateau (QTP) is one of the amplifiers of global\nclimate change. The headwater area of the Yellow River Basin (HYRB) on\nthe QTP is the dominant water source region for the whole Yellow River\nBasin (YRB). However, the sensitive responses of hydrological processes\nto the intensifying climate change are exerting high uncertainties to\nthe water cycle in the HYRB. The aim of this study was to investigate\nthe potential climate change under three Representative Concentration\nPathways (RCP 2.6, 4.5, and 8.5) and their hydrological impacts in this\nregion using the ensemble climate data from eight general circulation\nmodels (GCMs) and the Soil and Water Assessment Tool (SWAT). Compared to\nthe baseline (1976–2015), the projected climate indicated a rise of\n7.3–7.8% in annual precipitation, 1.3–1.9°C in maximum air\ntemperature, and 1.2–1.8°C in minimum air temperature during the near\nfuture period (2020–2059), and an increment of 9.0–17.9%, 1.5–4.5°C,\nand 1.3–4.5°C in precipitation, maximum and minimum temperature,\nrespectively, during the far future period (2060–2099). The\nwell-simulated SWAT modeling results suggested that due to a wetter and\nwarmer climate, annual average actual evapotranspiration (AET) would\nincrease obviously in the future (31.9–35.3% during the near future\nand 33.5–54.3% during the far future), which might cause a slight\ndecrease in soil water. Water yield would decrease by 16.5–20.1%\nduring the near future period, implying a worsening water crisis in the\nfuture. Till the end of this century, driven by the increased\nprecipitation, water yield would no longer continue to decrease, with a\ndecline by 15–19.5%. Overall, this study can not only provide\nscientific understanding of the hydrological responses to the future\nclimate in both semi-arid and alpine areas, but also contribute to the\ndecision support for sustainable development of water resources and\nprotection of eco-environment in the HYRB.