基于频率-强度联合分类的中国极端降水及人口暴露度时空演变特征

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

摘要

【目的】极端降水的演变及其引发的人口暴露风险是全球气候变化研究的重要议题。传统的单一维度(频率或强度)评估难以全面揭示极端降水演变的复杂性,旨在从“频率-强度”双重维度视角,解析中国区域极端降水演变格局,并定量识别人口暴露度变化及其驱动因素,为制定精准防灾策略及气候变化适应方案提供科学参考。【方法】基于多源融合降水产品(MSWEP)和中国历史人口空间分布千米网格数据集,采用K-means聚类方法构建了极端降水频率-强度联合分类体系。对比1981—1999年与2000—2020年两个时期,识别了极端降水类型的不同转变模式,并探讨了人口暴露度演变特征并量化气候、人口因子等的贡献。【结果】研究结果表明:极端降水强度与频率的演变呈现明显非对称性特征,全国约23%的区域发生了极端降水类型转变,其中以频率或强度单方面为主导的演化模式(如强度增强而频率不变)最为常见,而强度与频率同步变化的区域仅占约1%。此外,两个时期极端降水人口暴露度变化也表现出显著的空间异质性,全国约70%的区域暴露度呈上升趋势,华南和华东沿海地区增幅尤其明显。全国范围来看,人口变化是驱动暴露度变化的主要因素(贡献率约67%),气候变化的贡献次之(约30%),但在我国东北和西北地区,气候因子对暴露度变化的主导作用明显。【结论】研究成果揭示出我国极端降水在频率、强度两个维度上差异化演变的复杂特征,单一维度的传统评估可能低估或错估灾害风险,未来极端天气灾害风险管理需要基于极端降水类型演化的异质性制定差异化的防灾减灾及适应性策略。

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.

关键词

极端降水类型 / 人口暴露度 / 时空演变 / 强度 / 频率 / 气候变化 / 防灾减灾 / 时空演变

Key words

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

基金资助

国家自然科学基金项目(41807513)

2025年秦岭气候经济研究中心(院)开放研究基金项目(202503)