Chinese Wisdom: Investigating Future Patterns of Extreme Precipitation Based on the Twenty-Four Solar Terms

The Twenty-Four Solar Terms are an ancient and unique Chinese contribution, developed by agrarian laborers for the convenience of agricultural scheduling. Historically, each Solar Term has exhibited a significant correlation with climate change. Our study revisits and validates the Solar Terms’ sensitivity to regular precipitation metrics over the past half-century. We assessed the reliability of this temporal framework by comparing 30-day cumulative precipitation and the number of effective rainfall days around typical Solar Terms, along with the correlation of China’s Standardized Precipitation Index (SPI) with the Heihe-Tengchong Line, known as the Hu Line, during various Solar Terms. The research further investigates the correspondence between multiple scenarios of future extreme precipitation events, including Event-based Extreme Precipitation (EEP), and the Solar Terms. This study focuses on identifying which Solar Terms have historically been, and are likely to continue being, prone to extreme precipitation, as well as their spatial distribution patterns across China. The result indicates that under four different socio-economic pathways in future scenarios, over 55.2% of the regions in China will witness a concentration of extreme precipitation events during the Minor Heat and Major Heat Solar Terms. These events are predominantly expected to occur in the Qinghai-Tibet region, averaging over 10 instances every five years that exceed the 95th percentile for extreme rainfall, showing an increasing risk trend over time. This study not only enhances the cultural depth of our research but also fosters a profounder understanding of the cyclical patterns of extreme precipitation and the related flood risks it entails, offering a novel perspective for guiding flood prevention efforts and the study of extreme precipitation patterns.