A Precipitation Classification Scheme for China with Special Consideration of Extreme Events

This is the authors' abstract. We don't add key points for this paper.

Due to global warming, extreme weather and climate events are becoming more frequent, highlighting the need to explore the changing characteristics of precipitation, including extreme precipitation, in China. A clustering algorithm was developted to classify daily summer (June, July and August) precipitation in China from 1961 to 2020, considering spatial distribution, standard deviations, and frequency of extreme precipitation events. The result reveal six distinct precipitation climate zones, which differ from previous divisions. While overall precipitation has decreased in most regions, the frequency of extreme precipitation events has increased across all clusters, indicating a shift in precipitation distribution patterns. Analysis shows the weakened Baikal high and strengthened Mongolian cyclone influence the arid region in northwest China (cluster 1), with the lowest precipitation. The transition zone between the monsoon and arid region (cluster 2) is affected by the Mongolian cyclone, water vapor from the Indian Ocean, and variations in the monsoon boundary. Clusters 3 and 4 represent areas associated with summer monsoon advancement and retreat. In the Meiyu region, two distinct subregions special areas exist. Cluster 4 is primarily influenced by the East Asia-Pacific wave train. Clusters 4 and 5, despite similar climate drivers and proximity, differ significantly due to topographic differences and the degree of urbanization. Cluster 5 has a higher average precipitation, greater variability, and more frequent extreme events. Cluster 6 exhibits highest overall precipitation in the coastal areas of Guangdong and Guangxi, where abundant water vapor contributes to a higher frequency of extreme precipitation. In addition, anthropogenic activities and urbanization significantly influence the precipitation in Beijing-Tianjin-Hebei and Yangtze River Delta regions. This research proposes a precipitation classification scheme integrating multiple precipitation parameters, providing support for risk management and mitigation strategies in the face of increasing extreme precipitation events.