A comprehensive analysis of meteorological drought stress over the Yellow River basin (China) for the next 40 years

Abstract The complexity of climate system dynamics calls for more elaborate drought evaluation and trend projection under different future climate scenarios. In this study, the meteorological drought stress over the Yellow River basin (YRB) of China for the next forty years (2021–2060) is comprehensively evaluated based on meteorological simulations of eight climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) with three representative concentration pathway scenarios (RCP2.6, RCP4.5 and RCP8.5). The standardized precipitation evapotranspiration index (SPEI) is used as a metric of drought magnitude at multiple temporal scales, while the multi‐threshold run analysis is conducted for the definition of drought events and derivation of drought characteristics (e.g., frequency, duration and severity). The Mann–Kendall test is adopted as a universal tool to analyse the trends in climate variables (precipitation and temperature), multi‐temporal SPEI drought indices and drought characteristics (duration and severity). Our preliminary conclusions include that partially increasing precipitation and generally rising temperature are likely to be seen in the YRB from 2021 to 2060. More importantly, a warmer YRB may undergo either a nearly regular atmospheric regime (e.g., comparable to the baseline period of 1961–2000) with RCP2.6 scenario or significantly drying processes with RCP4.5 and RCP8.5 scenarios. Meanwhile, the enhanced spatiotemporal variability/heterogeneity of meteorological forcing (e.g., precipitation and temperature) and drought characteristics (e.g., magnitude, frequency, duration and severity) would also increase future uncertainty of meteorological drought stress over the YRB, such as the encounter of drought with long duration and/or high severity and relevant increasing trends. Understanding the spatiotemporal influences of specific climate and emission scenarios on projected drought vulnerability might help improving our knowledge of climate‐human interactions and selecting rational development strategy (like the low emission scenario of RCP2.6 or so) for regional adaptation to future climate change.