Future changes in the frequency of extreme droughts over China based on two large ensemble simulations

Abstract Future changes in the frequency of extreme drought events are vital importance for risk assessment and relevant policy making. But a reliable estimation their probability is intrinsically challenging due to limited available observations or simulations. Here, we use two large ensemble simulations, 50 members from CanESM2 40 CESM1 under future RCP8.5 scenario, elaborate projection 100-year (once century) different warming levels. It however necessary firstly remove systematic biases simulated temperature precipitation through bias-correction method based on quantile mapping. Droughts diagnosed with Standardized Precipitation Evapotranspiration Index (SPEI), which considers both potential evapotranspiration (PET, involving temperature). The results show that droughts increases continued global warming. Some differences between ensembles also observed, especially high China-averaged occur once century current climate by factors 1.52 (1.90) 1.44 (2.02) 1.5°C 2°C levels, respectively. A simple statistical scheme shows increasing mainly effect PET occurrence events, while almost keeps constant