中国沿海地区雨潮复合灾害联合分布及危险性研究

沿海地区极易受到极端降雨和高潮位引发的复合洪涝灾害影响。研究风暴增水和累积降雨同时发生的概率,设计雨潮联合分布函数,对提升沿海城市防洪除涝应对措施的有效性、减少城市复合洪涝灾害造成的损失具有重要意义。论文以1979—2014年中国沿海逐日最大风暴增水和邻近雨量站日累积降雨数据作为统计样本,采用Copula函数构建雨潮联合概率模型,并利用Kolmogorov-Smirnov检验、赤池信息准则、贝叶斯信息准则评价雨潮联合分布拟合优度,优选中国沿海雨潮联合概率分布函数模型。基于此模型,定量化设计中国沿海雨潮复合灾害情景。结果表明：在空间分布上,中国沿海雨潮复合灾害频次呈现明显的“两头多中间少”格局,其中,广东西部沿海、福建北部、浙江南部、山东及辽宁沿海频次相对较高;在50年一遇联合重现期下,北部湾、海南岛北部、浙江沿海、渤海湾部分沿海表现为极端降雨和较高的风暴增水,雨潮遭遇的复合灾害事件十分值得关注。研究结果在一定程度上揭示了中国沿海地区雨潮复合灾害的时空变化规律,并为复合灾害情景预测提供了定量化评估方案。

Joint distribution and risk of the compound disaster caused by rainfall and storm surge across Chinese coastal region

Coastal regions are extremely vulnerable to compound floods caused by extreme rainfall and strong storm surge. To improve the effectiveness of flood control measures in Chinese coastal cities and reduce the losses caused by urban compound flooding, it is important to analyze the joint probability of occurrence of extreme rainfall and strong storm surge and design the joint distribution function of daily storm surge and cumulative rainfall. In this study, we employed the Copula function to fit the joint probability distribution of storm surge and cumulative rainfall from 1979 to 2014. Then we used the Kolmogorov-Smirnov (K-S), Akaike Information Criteria (AIC), and Bayesian Information Criteria (BIC) statistical methods to obtain the optimal Copula function between storm surge and cumulative rainfall at each gauge alone the coast of China. Finally, based on the Copula method, we assessed the design value of compound scenarios of storm surge and rainfall in coastal China. The results indicate that the northern and southern parts of Chinese eastern coast have high frequency and the middle part has low frequency of compound disasters of strong storm surge and extreme rainfall. Western Guangdong, northern Fujian, southern Zhejiang, Shandong, and Liaoning provinces have a high frequency of compound disasters. Under the 50-year return period, the Beibu Gulf, northern Hainan Island, the coast of Zhejiang Province, and parts of the Bohai Bay have extreme rainfall and high storm surge. This study shows the temporal and spatial distribution of compound disasters of storm surge and rainfall in coastal China, and provides a framework for compound disaster scenario prediction.