Spatiotemporal evolution of extreme precipitation and population exposure in China based on a frequency-intensity combination classification

Abstract

[Objective] The evolution of extreme precipitation and the result ing population exposure risks are critical issues in global climate change studies. However, traditional assessments focusing solely on frequency or intensity cannot fully capture the complexity of these evolutionary processes. The evolving pattern of extreme precipitation across China from a dual-dimensional perspective of frequency and intensity is analyzed, and quantitatively identify changes in population exposure and the underlying drivers, thereby providing a scientific reference for formulating precise disaster prevention strategies and climate change adaptation plans. [Methods]The Multi-Source Weighted-Ensemble Precipitation(MSWEP) dataset and the China Historical Population Spatial Distribution Kilometer-Grid Dataset were employed. The K-means clustering method was adopted to establish an integrated classification system for extreme precipitation based on frequency and intensity. By comparing the periods of 1981—1999 and 2000—2020, different shifts in extreme precipitation type were identified, and the evolutionary pattern of population exposure as well as the contributions of distinct factors(e. g. climate, population) were quantitatively assessed. [Results] The results revealed that approximately 23% of the area in China experienced a shift extreme precipitation types, dominated by changes in either frequency or intensity alone(e. g., intensified intensity with unchanged frequency), whereas synchronous alterations in these two aspects only accounted for about 1%. Furthermore, changes in population exposure to extreme precipitation across the two periods displayed marked spatial heterogeneity, with an increase of exposure occurring in around 70% of the whole country, especially in southern and eastern coastal regions. At the national scale, population change dominated the change in exposure with national average contribution rate of 67% followed by climate change(~ 30%). However, in northeastern and northwestern China, climatic factor exerted a dominant influence on the changes in population exposure. [Conclusion] The findings reveal the complex characteristics of divergent evolution of extreme precipitation in China across both frequency and intensity. Traditional assessments relying on a single dimension might underestimate or misjudge disaster risks. Future management of extreme weather risks requires formulation of differentiated strategies for disaster mitigation, prevention and adaptation based on the spatial heterogeneity of evolution in extreme precipitation type.

Keywords

extreme precipitation type / population exposure / spatiotemporal evolution / intensity / frequency / climate change / disaster prevention and mitigation / spatiotemporal evolution