Hydrological impacts of climate change in the Yellow River Basin for the 21st century using hydrological model and statistical downscaling model

Abstract

In this study, impacts of climate change on streamflow in the Yellow River Basin are investigated. A semi-distributed hydrological model (SWAT) is calibrated and validated with records at Huayuankou, Lanzhou and Huaxian hydrological stations. Using outputs from a global circulation model (HadCM3), a statistical downscaling model (SDSM) and a combination of ‘bilinear-interpolation and delta’ are applied to generate daily time-series of temperature and precipitation (1961–2099). The generated data is integrated into SWAT to simulate streamflow under current and future climate conditions. The results show that the results modeled responding to SDSM fit natural or measured records better than responding to the combination method. Responses of runoff are assessed based on climate change scenarios constructed with SDSM using HadCM3 outputs. The projections show that the Yellow River Basin tends to become warmer. Annual average maximum and minimum temperature would rise by 5.0 °C in the 2080s. Annual precipitation would also increase by 54 mm–150 mm. The change in summer precipitation is most significant with an increase by 75 mm–115 mm. Annual average streamflow tends to increase gradually 17.9%–42.9% with time under scenario A2 and 11.5%–34.5% under scenario B2 relative to the current runoff (1960.5 m 3/s). Seasonal average streamflow would increase in spring, summer and winter in most time horizons under both scenarios, but decrease in autumn under scenario A2. Increasing runoff in spring and summer can favor crop growth, and increasing annual precipitation and runoff can alleviate water demand stress to some degree in the Yellow River Basin.