Analysis of system characteristics and vulnerability of rainstorm hazards in Shanghai

Based on nearly 30 years rainstorm data,this paper did dynamic research on the exposure,vulnerability of the Shanghai urban system under the impact of rainstorms.Under the rainstorm environment,the evolution process characteristic of the system was also studied.The result showed that the amount and the intensity of rainstorm indicate a significantly increasing tendency in recent 30 years;the rainstorm increased the hazard of urban waterlogging.While the impact of urban flood disaster caused by low intensity rainstorm is slight,extreme rainstorms still bring great threat to the city.In urban construction and development process,social system change,such as the design and the improvement of drainage capacity,rebuilding of old district and the improvement of housing standards,reduced urban waterlogging hazards and vulnerabilities.However,with the development of the urban area,new weak and hazardous regions emerge,thus it is necessary to contnue doing dynamic analysis on the disaster vulnerability of the system.