Characteristics of extreme hourly precipitation variability and influencing factors in the Central Yunnan Urban Agglomeration of China  

滇中城市群小时极端降水演变特征及其影响因素

作　　者：JIN Hanyu CHENG Qingping 金韩宇;程清平

机构地区：[1]College of Soil and Water Conservation,Southwest Forestry University,Kunming 650224,China [2]Yunnan Key Lab of International Rivers and Transboundary Eco-Security,Yunnan University,Kunming 650091,China

出　　处：《Journal of Geographical Sciences》2025年第4期886-920,共35页地理学报(英文版)

基　　金：National Natural Science Foundation of China,No.42461012;Yunnan Fundamental Research Projects,No.202201AU070064。

摘　　要：Understanding the evolutionary trends and driving factors behind extreme hourly precipitation(EHP)in typical urban agglomerations is crucial for predicting and preventing rapid floods.We collected hourly precipitation datasets from 31 observation stations in the Central Yunnan Urban Agglomeration(CYA)spanning from 2004 to 2020.Urban and rural observations were dynamically classified based on impervious surface fraction.Linear(Granger)and nonlinear causal methods(convergent cross-mapping and Liang–Kleeman information flow)were used to identify the causal impact mechanisms of large-scale circulation,environment and urbanization on EHP.Moreover,geo-detector further reveals the spatial influence of these factors and their interactions on EHP.Our findings revealed that EHP mainly occurred in the afternoon and at midnight.Also,the frequency and intensity of EHP in the CYA significantly(p≤0.05)increased from 2004 to 2020,especially in urban areas.The increasing rate in urban areas was higher than that in rural areas.However,the duration of EHP/hourly total precipitation exhibited a significant/nonsignificant decreasing trend with no significant difference between urban and rural areas.Causality tests and geo-detector indicated that EHP was impacted by natural variability and urbanization.Large-scale circulation indices such as the Pacific Decadal Oscillation,El Ni?o-Southern Oscillation,and Indian Ocean Dipole nonlinearly influenced EHP.Additionally,urban landscape layout,vegetation,and population variation may strengthen EHP by changing environmental factors such as temperature and relative humidity.Interactions exist between these factors and influence EHP,although large-scale circulation remains the dominant influence.With global climate warming and rapid urbanization in the CYA,the frequency and intensity of EHP may further amplify in the future.

关 键 词：evolutionary trends extreme hourly precipitation high-altitude urban agglomeration linear and nonlinear causality test 

分 类 号：P426.6[天文地球—大气科学及气象学]