Prediction of extreme floods based on CMIP5 climate models: a case study in the Beijiang River basin, South China

Abstract

Abstract. The occurrence of climate warming is unequivocal, and is expected to be experienced through increases in the magnitude and frequency of extreme events, including flooding. This paper presents an analysis of the implications of climate change on the future flood hazard in the Beijiang River basin in South China, using a variable infiltration capacity (VIC) model. Uncertainty is considered by employing five global climate models (GCMs), three emission scenarios (representative concentration pathway (RCP) 2.6, RCP4.5, and RCP8.5), 10 downscaling simulations for each emission scenario, and two stages of future periods . Credibility of the projected changes in floods is described using an uncertainty expression approach, as recommended by the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). The results suggest that the VIC model shows a good performance in simulating extreme floods, with a daily runoff NashSutcliffe efficiency coefficient (NSE) of 0.91. The GCMs and emission scenarios are a large source of uncertainty in predictions of future floods over the study region, although the overall uncertainty range for changes in historical extreme precipitation and flood magnitudes are well represented by the five GCMs. During the periods 2020-2050 and 2050-2080, annual maximum 1-day discharges (AMX1d) and annual maximum 7-day flood volumes (AMX7fv) are expected to show very similar trends, with the largest possibility of increasing trends occurring under the RCP2.6 scenario, and the smallest possibility of increasing trends under the RCP4.5 scenario. The projected ranges of AMX1d and AMX7fv show relatively large variability under different future scenarios in the five GCMs, but most project an increase during the two future periods (relative to the baseline period .

Current Efforts for Prediction and Assessment of Natural Disasters: Earthquakes, Tsunamis, Volcanic eruptions, Hurricanes, Tornados, and Floods

“…An approach to real-time prediction of oods generated by overtopping failure in natural dams was developed by Ma and Fu [220]. Studies of extreme oods were carried by Takeuchi [193] and Wu et al [188].…”

“…Due to climate warming, extreme precipitation is expected to be more intense and frequent [188], which may lead to oods and other natural disasters such as landslides. Also, other hydrologic processes, such as snowmelt, can increase the occurrence of oods [189][190].…”

Water allocation under future climate change and socio-economic development : the case of Pearl River Basin

“…Similar conclusions were drawn recently by Xiao et al (2013) for the West River, the Yujiang River, the Guijiang River, Hongshuihe River, and the North River (Beijiang) using five different GCMs under RCP4.5. Only Wu et al (2014) yielded different conclusions; they found low likelihood of increasing treads in high flow under the RCP4.5 scenario in the North River. Decreases in annual average low flows are projected for the whole basin.…”

“…In terms of future climate change, some studies preferred hypothetical climate change scenarios (Jiang et al, 2007;Li et al, 2011). Few studies used the output of GCMs to force the hydrological models in the Pearl River Basin (Liu et al, 2012;Wu et al, 2014;Xiao et al, 2013). However, more attention was paid to annual discharge and extreme flood events (Wu et al, 2014).…”

“…Few studies used the output of GCMs to force the hydrological models in the Pearl River Basin (Liu et al, 2012;Wu et al, 2014;Xiao et al, 2013). However, more attention was paid to annual discharge and extreme flood events (Wu et al, 2014). For a basin which is suffering from water shortage and saltwater intrusion in the dry seasons, it is in particular important to assess variations in low flow over the basin.…”