Research On Marine Disaster System Of Coastal City Based On Catastrophe Theory

From south to north,marine disasters have occurred every ocean area and coast of our country.The growth of economic loss caused by marine disasters is hard to decline.Given the seriousness of Marine disaster,the study of China's coastal city Marine disaster system,which has profound theoretical significance and practical significance.It can improve our country's Marine disaster response capacity to all kinds of major problems of Marine disasters.This dissertation reviewed the Marine disaster research at home and abroad,through the basic condition of the Marine disasters in China,China's existing problems in disaster prevention and mitigation and analysis of the causes,this dissertation mainly carry research on three aspects,including marine disaster mechanism of coastal city,Marine disasters loss prediction and the assessment of coastal city's disaster prevention and mitigation capacity.The results can be put into China's disaster prevention practice,which can also provide some useful reference for other coastal countries.It can gradually increase the consciousness of the whole society to the Marine disaster risk prevention.The main conclusions and innovation points embodied in the following respects:(1)Swallowtail catastrophic model was set up.Catastrophe potential function,profile of equilibrium equation and singular set were given,and bifurcation set equation was calculated.According to the space curved surface figure,from the people,the coastal city,environment three control variables analyze coastal city system's stability,discuss the change of system state with the control variable,more intuitive understanding of the coastal city's system state changes.(2)Grey-cusp catastrophic model is established to analysis the marine disasters loss.Through the empirical study of storm surge disaster loss prediction,time difference is calculated to predict the catastrophic year.According to the comparison between prediction result and actual data,it shows that this prediction method is featured by rationality and availability.According to the result of prediction on the Marine disaster,we can take effective measures on protection emphasis in advance to prevent severe instability mutation losses occured.(3)Using fuzzy matter-element evaluation method based on coefficient of variation for coastal urban disaster prevention and mitigation capacity's assessment,which has strong guiding significance for the whole construction of city planning.This method can objectively analyze the relations among fuzzy index,reveal the characteristic and mutual relation of index.By stratifying the index system,catastrophe evaluation method interprets the subjection between upper and lower index layer,and independence and relevance of the same index layer.It simplifies the calculation process.Moreover,introducing coefficient of variation in catastrophe evaluation method,can avoid subjective judgments on the relationship of the same index layer in the evaluation process.And ensure the objectivity of the evaluation results.It has been demonstrated by an example that the evaluation method calculation is simple,and results have a logical conclusion.It can improve the objectivity and scientificness of coastal cities' comprehensive disaster prevention and mitigation ability evaluation,and more practical.(4)Finally,according to the discussion of the present situation of China's marine disaster prevention and realistic demand,summed up the shortage of the building work of disaster prevention and mitigation capacity,several policy suggestions were given from early warning and forecasting,disaster prevention,disaster relief and disaster resilience.There are seven implementation methods: ocean development,optimization of marine disaster prevention management mechanism,improvement of marine disaster prevention laws and regulations,strengthen the team construction,improvement of disaster management information system of disaster prevention and mitigation,increasing investment in disaster prevention science research,popularization of Marine disaster prevention and mitigation education.