Abstract
The influence of climate change on the regional hydrological cycle has been an international scientific issue that has attracted more attention in recent decades due to its huge effects on drought and flood. It is essential to investigate the change of regional hydrological characteristics in the context of global warming for developing flood mitigation and water utilization strategies in the future. The purpose of this study is to carry out a comprehensive analysis of changes in future runoff and flood for the upper Huai River basin by combining future climate scenarios, hydrological model, and flood frequency analysis. The daily bias correction (DBC) statistical downscaling method is used to downscale the global climate model (GCM) outputs from the sixth phase of the Coupled Model Intercomparison Project (CMIP6) and to generate future daily temperature and precipitation series. The Xinanjiang (XAJ) hydrological model is driven to project changes in future seasonal runoff under SSP245 and SSP585 scenarios for two future periods: 2050s (2031–2060) and 2080s (2071–2100) based on model calibration and validation. Finally, the peaks over threshold (POT) method and generalized Pareto (GP) distribution are combined to evaluate the changes of flood frequency for the upper Huai River basin. The results show that 1) GCMs project that there has been an insignificant increasing trend in future precipitation series, while an obvious increasing trend is detected in future temperature series; 2) average monthly runoffs in low-flow season have seen decreasing trends under SSP245 and SSP585 scenarios during the 2050s, while there has been an obvious increasing trend of average monthly runoff in high-flow season during the 2080s; 3) there is a decreasing trend in design floods below the 50-year return period under two future scenarios during the 2050s, while there has been an significant increasing trend in design flood during the 2080s in most cases and the amplitude of increase becomes larger for a larger return period. The study suggests that future flood will probably occur more frequently and an urgent need to develop appropriate adaptation measures to increase social resilience to warming climate over the upper Huai River basin.
Highlights
Climate change associated with global warming, mainly owing to the rise of greenhouse gas emissions in the atmosphere, has caused an increase of the evapotranspiration over the land surface, which in turn has accelerated the hydrological cycle and altered the hydrological element (Arnell and Gosling, 2013; Schewe et al, 2014; Wang et al, 2017)
It is necessary to assess the performances of the chosen models (i.e., BCC, CanESM, CESM, and MRI models) in order to investigate the influences of climate change on seasonal runoffs and floods in the Xixian basin
This paper quantitatively evaluates the changes of future floods in response to climate change coupling of CMIP6 models and XAJ hydrological model in the Xixian basin
Summary
Climate change associated with global warming, mainly owing to the rise of greenhouse gas emissions in the atmosphere, has caused an increase of the evapotranspiration over the land surface, which in turn has accelerated the hydrological cycle and altered the hydrological element (Arnell and Gosling, 2013; Schewe et al, 2014; Wang et al, 2017). A warmer climate will intensify very wet and very dry weather and climate events These extreme events are expected to trigger further, leading to increasing weather-related hazards such as destructive flooding or drought, which possibly pose tremendous societal, economic, and environmental challenges around the world. It is of great necessity to enhance the understanding of future changes in the hydrological responses and flood characteristics under the context of climate change to provide support for appropriate adaptation strategies and water resources management
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