Unveiling the link between extreme precipitation events and flood disasters in China: from a 3D perspective

Abstract. Extreme precipitation events and their triggered flood disasters have received increasing attention owing to their severe threats to human lives and socioeconomic development. However, there is still a lack of research on their evolutionary characteristics and driving factors from a three-dimensional (3D) event-based perspective. Here, we developed a 3D automatic recognition algorithm based on the connected component 3D algorithm. This method was applied to investigate the 3D characteristics of 632 flood-causing precipitation (FCP) events in China from 2000 to 2023. The associated flood disasters and their underlying driving factors were further analysed. The FCP events with larger accumulated magnitudes and affected areas are mainly distributed in the center of Southern China (SC) and Northern China (NC), mostly moving eastward with longer distances and lifespans. FCP-induced flood disasters are more severe in the SC and parts of the NC, while a relatively higher proportion of flood disaster losses are concentrated in the southeastern fringe of the Qinghai-Tibetan Plateau (TP) and southwestern China (SWC). In other words, flood disasters caused by FCP in China exhibit the changing characteristics of "high impact-low losses ratio" in SC and NC and "low impact-high losses ratio" in TP and SWC. Notably, despite the increase in 3D characteristics of FCP events over the past two decades, flood disasters have shown a significant reduction, except for the direct economic losses. Driving factor analysis indicates that the combination of precipitation and environmental factors have the greatest explanatory power for most flood disasters in China, while human activities have a prominent impact on the flood disasters in the center of SC and NC. These findings provide new insights into the characteristics of FCP events and their associated flood disasters from a 3D event-based perspective.