变化环境下城市洪水演变驱动机理——以北京市温榆河为例

气候变化和人类活动被认为是城市洪水演变的主要驱动因素，不同区域气候变化和城市化对洪水演变的影响不尽相同，科学识别城市洪水演变的关键驱动要素、量化气候变化与城市化对城市流域洪水演变的影响是城市洪水管理的重要依据。本文以高度城市化的北京市温榆河流域为例，以季节降雨量、气温、流域前期湿度、不透水面积比及流域内地下水埋深作为潜在驱动要素，对温榆河夏季不同概率的洪水建立GAMLSS模型，分析探讨城市流域洪水演变的主要驱动机制。研究结果表明:温榆河流域夏季不同概率的洪水在研究期均呈现出非一致性特性；城市不透水面积的扩张和降水是温榆河流域夏季洪水变化的主要驱动要素，不同等级洪水的变化具有不同的驱动机制，高于概率70%的小洪水的变化主要受到流域下垫面变化的影响，而小于概率45%的低频洪水的变化主要受降水的影响。

Driving mechanisms of urban floods under the changing environment: case study in the Wenyu River basin

Climate change and urbanization are regarded as the major driving factors for floods in urban watersheds. Many studies have witnessed the impact of climate change and urbanization on streamflow in different regions are different. Identification of driving factors for floods and quantifying the impact of climate change and urbanization on urban flood variation are important significance for floods management in urban watersheds. The Wenyu River basin in Beijing, which has undergone a highly urbanized process, is selected as the study area in this study. The GAMLSS model was developed for different probability of discharges in summer, with seasonal precipitation, air temperature, antecedent wetness, impervious areas and groundwater level as covariates, to study the mechanism of discharge variation in urban watershed. Results showed that all of the different probability of discharges in summer showed the nonstationary characteristics; increasing impervious areas and precipitation are major driving factors for floods in the Wenyu River basin. Different probability of discharge has different driving mechanism, smaller discharges with probability higher than 70% was mainly affected by changes of land use on ground surface, while the greater one, especially the extreme floods below 45% probability were mainly influenced by precipitation.