Research Of Natural Disaster Database Construction And Risk Assessment In Yangtze River Delta Region

Currently, the increasingly serious disasters have caused great concern of the Chinese government and academia. The natural disaster risk assessment is a prevention-oriented, proactive disaster prevention and mitigation measures. It is the basis and foundation to carry out a comprehensive disaster reduction and the development of emergency management countermeasures. It is also the focus of the field of disaster research. The frequency, intensity and loss of natural disasters are constantly increasing in the context of global warming and sea level rise. China’s Yangtze River Delta region (the whole territory of Jiangsu, Zhejiang and Shanghai) is selected as the study region for research of natural disaster risk assessment. The research which is based on theory and the latest results in natural disasters apply scenario analysis and GIS. The paper discusses the establishment of natural disaster classification system, collecting relevant disaster data, construction of natural disaster metadata standard and database. It provides a scientific basis for government departments to build a regional risk management system and promote the work of disaster prevention and mitigation. The followings are main conclusions of the research1. Determine the properties and classification of natural disasters according to circle structure based on Earth System Science. In this classification system, four types of disasters which are meteorological disaster, hydrological disaster, geological disaster and biological disaster correspond to atmosphere, hydrosphere, lithosphere and biosphere in the earth surface system structure. The system is conducive to the identification and analysis for the environment of hazards and the development of targeted vulnerability assessment and risk analysis. The classification system which has a good compatibility and scalability is an important reference for construction of natural disaster metadata standard and the Yangtze River Delta natural disaster database. It with reference to the current international classification method of natural disaster, but also take into account the domestic disaster research and classification used by related departments for a long time.2. Collection of natural disaster history data in the newspapers should focus on three issues:the semantic understanding of text and natural disaster data extraction, description and matching on temporal and spatial position of natural disaster event, accuracy and reliability assessment of natural disaster data or text information. After data preprocessing and included work completed, each record need a scientific data coding as identifier by set a unique serial number. Natural disaster type encoding method can be used to identification code and classification codes, natural disaster event code can be used to the number and date.3. Develop design ideas of natural disasters metadata standards by analyzing definitions, characteristics, classification as well as the role of metadata and metadata standard. Completed the construction of natural disaster metadata standards, can provide services, data management, and database development for natural disasters and also provides support for data sharing of natural disasters. Preparation of the natural disaster metadata standards, defines the content, structure and format of the natural disasters metadata. Specific standard covers6entities,33elements, and another36sub-elements. Each metadata element has nine properties for restrictions and instructions.4. Comparative analysis on the domestic and foreign main natural disaster database, summarizing the advanced international experience and China’s existing problems, puts forward the ideas of natural disasters in the Yangtze River Delta database, mainly includes three aspects which are the construction principle, the overall design and the environment of hardware and software. Completed the structural design of Yangtze Delta natural disasters database, established a conceptual data model and introduced the structure and relationship between data tables in detail. Finally, the paper discussed the management and maintenance of Yangtze River Delta natural disasters database, including user management, data management, database maintenance, database backup and recovery.5. Analyze spatial and temporal patterns and characteristics of space-time evolution of natural disasters for the past60years in the Yangtze River Delta region. Research of the annual and monthly changes of natural disasters from the provincial and county levels and analyze the number of natural disasters space distribution. The high incidence of natural disasters is concentrated in the coastal counties. More serious natural disasters of the central and southern parts of the Yangtze River Delta region compared to northern. Established two order linear regression prediction model to analyse and predict the future trend of natural disasters in the Yangtze River Delta region. The number of natural disasters in the Yangtze River Delta region is on the rise to2020according to the calculation results. Expected to2016, number of natural disasters will be back in2010. By2020, there will be a new historical peak.6. In a return period of10years typhoon disaster scenario, loss rates were low in counties, lower vulnerability and middle vulnerability regions have a considerable area. The majority of the counties belong to the low risk. In a return period of50years typhoon disaster scenario, most regions had a high vulnerability and the low vulnerability counties only scattered. Area of low risk regions is substantially reduced and Jiangsu and Zhejiang had many medium-risk or high-risk counties. In a return period of100years typhoon disaster scenario, Most of the Yangtze River Delta region counties show higher vulnerability or high vulnerability. The middle regions are almost all high-risk or high-risk areas. There are a large number of medium-risk areas in northern. Southern had a relatively low risk.7. Lianyungang, Yancheng, Yangzhou, Shanghai, Shaoxing, Lishui, Taizhou region presents high or higher vulnerability and Changzhou, Suzhou and other regions to render the overall low vulnerability in a return period of10years flood disaster scenario. The central region of Yangtze River Delta has a higher risk, a lower risk of large areas in Northern Jiangsu and central and southern of Zhejiang. The risk of southern Jiangsu, northern Zhejiang had improved in a return period of50years flood disaster scenario. Lower vulnerability areas are down to Suichang and Liyang. The low-risk area reduced by about half and high-risk areas expanse to the north and south. Majority of the Yangtze River Delta region presents high vulnerability in a return period of100years flood disaster scenario. High-risk areas of the Yangtze River in central region continues to expand, lower risk regions except for Lishui district in the southwestern Zhejiang is represented by a small area.8. In a return period of10years rainstorm disaster scenario, the counties in Yangtze River Delta region belong to the low vulnerability and lower risk. In a return period of50years rainstorm disaster scenario, the overall vulnerability of the Yangtze River Delta region is on the rise and the vast majority of regions have a high vulnerability. Lower vulnerability only sporadic distributed in central and northeastern Zhejiang province. The moderate risk regions increased more area. Low-risk regions are mainly distributed in the northern part of Jiangsu and southern part of Zhejiang. In a return period of100years rainstorm disaster scenario, the vulnerability of Yangtze River Delta region continues to rise. There are a large number of high vulnerability areas and only a small amount of medium vulnerability areas in Jiangsu and Zhejiang. The original high-risk region developed to north rapidly and southern Zhejiang has a relatively low risk and low risk region.9. In a return period of10years storm surge disaster scenario, coastal regions of Yangtze River Delta generally showed lower-middle vulnerability. The overall level of risk is not high. In a return period of50years storm surge disaster scenario, most coastal regions of Yangtze River Delta are in the middle vulnerability. High vulnerability areas have increased significantly and the risk is mainly concentrated in central coastal zone of Yangtze River Delta. In a return period of100years storm surge disaster scenario, vast majority of counties in the coastal regions of Yangtze River Delta presented high vulnerability and in a high-risk level. High-risk areas continue to expand and only the northern areas of Jiangsu and north along the coast of Zhejiang have a small amount of regions which showed a relatively low risk.10. In a return period of10years drought disaster scenario, Yangtze River Delta region as a whole does not appear high vulnerability areas. The small amount of low vulnerability areas occurred mainly in northern Jiangsu, central Zhejiang and Zhoushan districts. High-risk areas are mainly concentrated in the middle of Yangtze River Delta region. The lowest risk areas are located in southern Zhejiang. In a return period of50years drought disaster scenario, the central and northern parts of Yangtze River Delta region there had been a certain amount of high vulnerability counties. Lower vulnerability areas are only down in Dongyang City and Jinhua City. High-risk area has expanded in the middle of Yangtze River Delta region. In a return period of100years drought disaster scenario, majority of counties in Yangtze River Delta region show high vulnerability and there are no longer relatively low vulnerability areas and low-risk areas. In addition to the overall level of risk of the western and southern parts of Zhejiang province was relatively low, the rest of the regions are almost in the middle and high level of risk.