Characterization of intra-event patterns of heavy rainfall events in China during 2008–2019 by machine learning
摘要
The escalating intensity and frequency of heavy rainstorms pose critical challenges to natural ecosystems and human living environments. Understanding the intra-event pattern (IEP) of heavy rainfall events is crucial, as it significantly influences hydrological processes such as infiltration and runoff, which in turn govern the timing and scale of water-related disasters. This study proposes a machine learning framework that combines fuzzy c-means clustering with a real-coded genetic algorithm to characterize IEPs across seven engineering climate zones in China. Based on 12-year hourly rainfall data, the analysis revealed four key findings: (1) a temporal restructuring of rainfall events, marked by the growing dominance of short-duration, high-intensity storms and the decline of long-duration events in specific inland regions, indicating shifts in climatological dynamics; (2) a quadripartite clustering structure consistently emerging across all study zones, identifying four IEPs with distinct peak timings; (3) the parametric representation of normalized IEP curves and hyetographs using a two-parameter beta distribution, ensuring precision and flexibility; (4) detection of double-peak rainfall events through membership degree analysis, revealing multi-peak structures often overlooked in conventional models. These findings highlight the necessity for region-specific stormwater management strategies and climate-resilient infrastructure design, particularly in high-risk alluvial regions vulnerable to flash floods and waterlogging. By integrating IEPs into a systematic spatiotemporal characterization framework, this research contributes meaningfully to advancing urban climate resilience, flood risk mitigation, and sustainable stormwater management under evolving climate conditions.