Future projection of heat waves over China under global warming within the CORDEX-EA-II project

Driven by four global climate models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) (i.e., CNRM-CM5, EC-EARTH, GFDL-ESM2M and MPI-ESM-LR) under the Representative Concentration Pathway8.5(RCP8.5) scenario, projections for future changes in heat waves over China are performed by Weather Research Forecasting(WRF) model simulations for future (FTR, 2031-2055) and present (1981-2005) periods. Six heat wave indices are applied to characterize heat waves based on their frequency, duration, magnitude, intensity, accumulated occurrence days and severity. Analyses show that notable increases in heat wave indices cover all of China. More areas will endure more frequent, longer lasting and more severe heat waves in the coming decades. The increasing tendencies of heat wave indices in the FTR period are more significant than those at present, indicating that heat waves will intensify more rapidly in the future. The impacts of climate changes on the accumulated properties of heat waves are more substantial than those on the individual aspects of heat waves. It is also projected that stronger heat waves with prolonged durations and more severe magnitudes will occur more often in the FTR period, whereas relatively weaker heat waves would occur less often. Hence, the occurrence of extreme heat waves shows a more remarkable increase than the occurrence of moderate heat waves. The changes in heat waves can be largely explained by the changes in the dominating high-pressure systems.