基于信息扩散方法的中国台风灾害年月尺度风险评估

利用1985—2014年中国台风灾情和社会经济资料,对中国年和月尺度的台风直接经济损失的时空变化规律进行分析,并采用信息扩散方法开展损失风险评估,为提高台风灾害风险管理能力提供参考。结果表明:全国年及7—9月各月的直接经济损失均呈增加趋势。直接经济损失的月际变化特征明显,8月致灾台风个数多、损失最严重;与1985—1994年相比,后两个10年年内变化幅度大,且9一10月损失大于6—7月。随着直接经济损失水平的增加,发生中、高风险的地区逐渐减少,年直接经济损失≥50亿、≥100亿元水平下,浙江风险概率为全国最高。在10年、20年、30年一遇三个风险水平下,浙江、广东、福建、广西年直接经济损失一直维持特重灾等级;20年、30年一遇风险水平下,北方地区的山东与辽宁年和8月、河北年台风直接经济损失也达特重等级,防台应对不容忽视。

Annual and Monthly Risk Assessment of Typhoon Disasters in China Based on the Information Diffusion Method

By employing the typhoon disaster information, social and economic data of China during 1985-2014, spatio-temporal characteristics of annual and monthly typhoon direct economic losses in China were analyzed. Risk assessments were carried out by using the information diffusion method to provide reference for improving the capability of typhoon disaster risk management. The results are as following. Annual and monthly typhoon-caused direct economic losses from July to September in China show slightly increasing trends during 1985-2014. The monthly variations of direct economic losses are obvious, particularly in August, in which the disaster-caused typhoons are most and the economic losses are most serious in a year. Compared to the period 1985-1994, the range of monthly variations become greater and total economic losses in September and October are greater than in June and July in the recent two decades, i.e., 1995-2004 and 2005-2014. Along with the increasing of direct economic losses levels, the regions with middle and high risk levels are decreasing gradually. Under the condition with annual direct economic losses greater than or equal to 5 or 10 billion RMB yuan, risk probability in Zhejiang Province is the highest in China. Under the three risk levels (returning period=10, 20, 30 years), annual direct economic losses in Zhejiang, Guangdong, Fujian and Guangxi are kept at the specially serious degrees. Under the risk levels with 20 and 30 years returning periods, annual and monthly (August) direct economic losses in Shandong and Liaoning and annual losses in Hebei have also reached the specially serious degree. Thus, the defense response to typhoon should not be neglected in these regions.