Abstract:
Guangzhou has experienced frequent extreme rainfall events with increasing urban flood risks in recent decades. Based on the rainfall data from 80 provincial meteorological stations in Guangzhou during 2012—2021, and the minutes-level rainfall records from five national meteorological stations over the past 60 years, this study investigates the spatiotemporal distribution characteristics of extreme precipitation. The Chicago rainfall pattern (storm hyetograph) method and equal frequency analysis method were employed to synthetically construct design rainfall patterns for both short- and long-duration rainfall events, respectively. The main findings are as follows: (1) The spatial distribution of the maximum 1-hour precipitation in Guangzhou exhibits a pattern of higher values in central Cuangzhou and lower values in the northeast and southwest, with the highest value observed in southern Zengcheng. In contrast, the maximum 24-hour precipitation is higher in northeast-high and lower in the southwest, with a high-value center located at the junction of Conghua and Zengcheng, while low-value areas extended from Panyu to Nansha, Indicating a notable spatial heterogeneity. (2) For short-duration design rainfall patterns, the peak positions at Guangzhou and Huadu stations vary considerably with rainfall duration, accompanied by large fluctuations in the peak position coefficient. In comparison, The peak position coefficients at Conghua and Zengcheng stations remain relatively stable, followed by those at Panyu station. The peak rainfall intensity is the strongest at the Zengcheng station, followed by the Panyu and Conghua stations, whereas Guangzhou and Huadu stations exhibit comparatively lower peak rainfall amounts. (3) For long-duration design rainfall patterns, the maximum 1-hour cumulative rainfall intensity ranks as follows: Guangzhou > Huadu > Zengcheng > Panyu > Conghua. In terms of the proportion of accumulated rainfall occurring at the peak time, the order is Panyu > Guangzhou > Zengcheng > Huadu > Conghua.