Projected changes in extreme precipitation events over China in the 21st century using PRECIS

ABSTRACT:

This study evaluates possible spatial and temporal changes in precipitation extremes over China under Representative Concentration Pathway (RCP) scenarios using the regional climate model system ‘Provide Regional Climates for Impacts Studies’ (PRECIS), driven with HadGEM2-ES. The extreme precipitation indices applied are consecutive dry days (CDDs), simple daily precipitation intensity index (SDII), maximum consecutive 5 d precipitation (RX5D) and total precipitation amount on extremely wet days (R95P). PRECIS can satisfactorily reproduce the spatial distribution of extreme precipitation indices compared to the observed data. By the end of the 21st century, CDD and SDII are projected to increase under all RCP scenarios in southern China, and R95P and RX5D are projected to increase under RCP4.5 and RCP8.5 scenarios, which indicates the possible increasing risks of prolonged dry spells and heightened floods in these regions. In northern China, CDDs are expected to decrease, while other indices are expected to increase in the future, implying a decrease in the risk of prolonged drought periods and an increase in flood risk; this pattern is most prominent over northwestern China. For the temporal evolution of the extreme precipitation indices, the change rates are most significant under the RCP8.5 scenario. Compared to present-day levels, from low to high emission scenarios, CDDs would decrease by ~1-10%, SDII would increase by ~6-14%, R95P would increase by ~9-21%, and RX5D would increase by ~6-26%, respectively, suggesting that dry extremes would be alleviated, while wet extremes would become more pronounced in general over China toward the end of the 21st century.