Enlarging Difference Between Persistent Extreme Precipitation and Fixed-Time Extremes in China

Abstract

Extreme precipitation occurs persistently in nature and has caused a series of social, environmental, and ecological problems. However, most analyses of extreme precipitation are conducted at fixed-time intervals, which may lead to misconceptions of the spatial-temporal changes and causes, hindering scientific understanding and engineering prevention. In this study, we quantified the differences between persistent and fixed-time extreme precipitation in China using historical observations from over 2,400 meteorological stations between 1960 and 2019 and future simulations from 10 global climate models during 2021–2100 under three scenarios (SSP126, SSP370, and SSP585). The national average annual-maximum persistent precipitation (Rx1event) was 2.5 times greater than extremes for fixed-time precipitation (Rx1day) historically, and 2.8 times higher in the future period. Although Rx1day increased faster than Rx1event in the historical period, it is projected to grow more slowly than Rx1event in all three future scenarios. Both Rx1day and Rx1event exhibit Hook structures responding to temperature. The Peak temperatures of Hook structures are expected to rise by 2–6°C with projected future climate change, causing the precipitation-temperature response curve to shift to the high-value direction, thereby increasing the magnitude of Rx1day by 5%–12% and Rx1event by 22%–29%. Our research enlightens disaster preventers and researchers to pay more attention to persistent extreme precipitation, especially in areas where it differs significantly from the fixed-time scale.