Article
YIN Jie, DAI Erfu, WU Shaohong, PAN Tao
Typhoon disasters cause great losses in coastal regions of China, and typhoon disaster risk assessment can provide scientific basis for disaster loss prevention. It is a basic work to assess its risk quantitatively in discussion on the relationship between typhoon intensity grade and disaster loss. In this paper, 174 typhoon paths data and disaster situation data from 1954 to 2008, and intensity grade information for each typhoon event from track dataset are used to analyze the relationship between typhoon intensity grade and 8 loss indices. The typhoon intensity grade is characterized by average wind speed. The loss indices include crop afflicted area, crop failure area, afflicted population, mortality, injuried, settlement population, collapsed buildings, and direct economic loss, which belong to four kinds of hazard resilient society (crops, population, house and economy). Based on typhoon wind theory, the affected range of each typhoon is extracted by doing buffer in spatial analysis module on ArcGIS9.3. According to the ranges, the 8 indices for loss rates could be calculated. The relationship between typhoon intensity grade and disaster loss rates are fitted by statistical method, and the loss rate curves are obtained subsequently. The loss rate curves are showed in exponential forms. Based on the typhoon intensity grade division standard and loss rate curves, the scheme of typhoon disaster loss criteria is established, which could be divided into four grades: slight, light, medium and severe. In the criteria, each grade could be characterized by 8 loss indices. The results indicate that loss rates are exponentially increasing with typhoon intensity grade, namely, the higher the intensity grade, the larger the amount of losses. When the intensity grade is 4, the loss rates are increasing sharply. Crops are the most affected in four kinds of hazard resilient society when typhoons landing, and in the severe case, 63.25% of crops area suffers from typhoon disaster. However, mortality rate, injury rate, collapsed buildings rate and direct economic loss rate are relatively low, which indicate that China has the capacity of calamity reduction to avoid large losses. The typhoon disaster loss rate criteria established in this paper could be suitable in China and useful in quantitative vulnerability and risk assessment in further studies.