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
climate change. The headwater area of the Yellow River Basin (HYRB) on
the QTP is the dominant water source region for the whole Yellow River
Basin (YRB). However, the sensitive responses of hydrological processes
to the intensifying climate change are exerting high uncertainties to
the water cycle in the HYRB. The aim of this study was to investigate
the potential climate change under three Representative Concentration
Pathways (RCP 2.6, 4.5, and 8.5) and their hydrological impacts in this
region using the ensemble climate data from eight general circulation
models (GCMs) and the Soil and Water Assessment Tool (SWAT). Compared to
the baseline (1976–2015), the projected climate indicated a rise of
7.3–7.8% in annual precipitation, 1.3–1.9°C in maximum air
temperature, and 1.2–1.8°C in minimum air temperature during the near
future period (2020–2059), and an increment of 9.0–17.9%, 1.5–4.5°C,
and 1.3–4.5°C in precipitation, maximum and minimum temperature,
respectively, during the far future period (2060–2099). The
well-simulated SWAT modeling results suggested that due to a wetter and
warmer climate, annual average actual evapotranspiration (AET) would
increase obviously in the future (31.9–35.3% during the near future
and 33.5–54.3% during the far future), which might cause a slight
decrease in soil water. Water yield would decrease by 16.5–20.1%
during the near future period, implying a worsening water crisis in the
future. Till the end of this century, driven by the increased
precipitation, water yield would no longer continue to decrease, with a
decline by 15–19.5%. Overall, this study can not only provide
scientific understanding of the hydrological responses to the future
climate in both semi-arid and alpine areas, but also contribute to the
decision support for sustainable development of water resources and
protection of eco-environment in the HYRB.