| With the continuous development of the global economy and global climate change,bring about climate warming,resource shortages,environmental degradation.Drought,earthquakes,tsunamis,acid rain,haze,floods,mud-rock flow,land subsidenceand other types of natural disasters pose severe challenges to human life and the living environment.The contradiction between population,resources,the environment has become increasingly prominent,increasingly complex,an increasing number of uncertain factors,mankind has entered the era of global risk,the risk is everywhere,ever.Drought disaster is one of the worldwide prevalence of natural disasters,the harm is the most serious form of natural disasters,in recent years,droughts become more frequent,drought losses increasingly severe,brought great harm to human social life and economic development.The drought not only bring a heavy disaster to poor and backward countries,but also a huge loss to the developed and developing countries.Successive years of drought often cause catastrophic famine in poor countries or regions,leading to regional unrest,disease-prone,bring huge disaster to human.Because of the drought possess a slow onset and gradual change,a wide range,great harm etc.different characteristics compared with other natural disasters,so it is difficult to find out the drought essence comprehensively.In the past,it can only take passively emergency measures for drought,lack of full understanding of the drought cause,unable to grasp drought characteristics and law of development,response measures single-sided,take a crisis management mode,which caused the result is that a drop in grain production,drinking water difficulties,factories and mines were forced to intermittent production or discontinued,the ecological environment deterioration and economic development slowdown etc.The traditional drought crisis management mode can not effectively prevent or reduce drought hazards,in order to effectively prevent and resist drought,it is should that change "crisis management" to "risk management"for the drought management,and risk management is increasingly becoming keen research topic worldwide,risk single management is being developed into a comprehensive risk management,some scholars have pointed out that the "risk management" is one of the national prosperity cornerstones.In our country,it is also drought-prone,arid-water shortage contradiction become increasingly prominent,seriously hampered the development of the economy.In drought management which is in passive anti-anti situation for a long time in China,it is mainly take emergency drought mitigation measures,lacks comprehensive drought planning programs,can not be targeted to formulate operability well and measures effective anti-drought contingency plan,management methods lagged behind,scientific and technological means are low,it is a"crisis management" mode.completely In contrast,drought "risk management" is to drought carry through scientific management mode,three aspects management is included that the pre-disaster management,disaster period management and post-disaster management.It is that mainly take prevention and early warning measures prior to the occurrence of disasters,take drought disaster may appear nipped in the bud or the growth of the state,to minimize the probability of drought disasters.For those drought disasters which can not be avoided,it can be made control measures in advance,thus can fully prepared to deal with disasters and mitigate the damage.In post-disaster,in addition to rescue relief recovery and reconstruction,but also need summarize reasons of drought and drought results,take post-disaster evaluation in order to lays down countermeasure and plan which is of more comprehensive and effective measures for drought preparedness in the future.Drought risk management,the aim is that can reach prevention drought initiativly,and actively respond to drought risk,reduce or low drought losses or damaging effects.In recent years,drought is increasingly frequent and drought losses increasingly heavy in China,2009-2010 severe drought in southwest China which caused a large area of farmland crops died out,rivers dry up,people and livestock drinking water serious difficulties for drought and serious economic losses,sounded the alarm to China's drought management once again.In this context,this paper take Guangxi Rocky area as the research object and Tiandong County as typical,based on related research in the world,carried out drought risk management,to improve the regional prevent-drought and resist-drought ability.This paper follows closely the drought risk management content,the main aspects work as follows.(1)Starting from the basic characteristics of the Guangxi Rocky,analyzes its drought causes and drought characteristics,and selected influencing factors from the natural,social,economic and other aspects as the evaluation indicators to evaluate the degree of drought vulnerability of the disaster bearing body comprehensive based on entropy weight fuzzy comprehensive evaluation method,the results of analysis and evaluation showed that the degree of drought vulnerability reach to serious in most areas of Guangxi Rocky 30 counties(cities,districts),the results of its evaluation on how to reduce the degree of vulnerability of the region play a guiding role,and how to reduce blindness and risk for preventing and resisting drought decisions played an important role.(2)Drought identify is the basis of drought risk management,drought impact factors generally have precipitation,temperature,evaporation,scorching wind,soil,topography,geomorphology,hydrogeology,crop structure,water supply conditions and regional characteristics etc,in reference to the existing drought identification index system,it is the first time that applying entropy method to distinguish and evaluate and analyse dryland agriculture easy to drought area and drought months,quarterly transformation trend and the degree of drought based on water balance of supply and demand evaluation index between months and quarter during the year,and water supply and demand relative index evaluation indicator got by mean value approach,and the evaluation results were compared with the conventional traditional analysis methods.The results show that the entropy weight method can not only identify the degree of drought,but also to recognize the transformation trend of the drought.(3)Based on lack drought historical data of the research area and drought information incomplete case,take Tiandong County agricultural drought as an example to carry through risk assessment study using fuzzy information distribution method and beyond the limits of probability methods.Meanwhile,carry out a risk assessment and zoning risk map research of Guangxi Rocky agriculture and the people drink using information diffusion method.And using the traditional frequency calculation and classification method to analyse the drought characteristics of Guangxi Rocky area and drought risk maps zoning.(4)In order to forecast drought more accurate,provide the scientific basis for laying down effective resisting drought early warning plan,this paper on the basis of the annual rainfall forecast useingthe autoregressive integrated moving average ARIMA model,Elman neural network model,wavelet network analysis model,gray system theory model,through a variety of combinations,establish the preferred combined forecasting model based on entropy weight,the prediction accuracy of the model has been improved,and the fitting degree greatly improved,and provides new methods and theoretical support for drought prediction.(5)Analysis the causes of 09-10 year severe drought in Guangxi,and carry out the research on water tank protection against drought and fight against drought early warning.Aim at the impact of the 09-10 year severe drought,determine the size of the family water tanks volume,according to the relationship between the water tank water level and the number of days of available water supply to determine early warning response level bwtween the number of days of continuous no rain day and the remaining days of water supply.(6)Carry out Guangxi fight against drought social and economic benefits analysis,results show that the effectiveness and investment ratio(benefit cost ratio)for long-timeaverage annual value is 24.3,while severe drought is 12.4,even for moderate drought can reach more than 70,fight against drought benefit remarkable.This paper take Guangxi Rocky area as the research object and its Tiandong county as typical,starting from drought risk management models,analyze the existing problems in flight against drought and drought disaster alleviation,and according to the drought characteristics of this region,around the current domestic and international research hotspot and difficult problems,carry out analysis and evaluation for drought causes and vulnerability of Guangxi Rocky area,drought risk identification and evaluation,assessment and zoning,as well as drought forecasting study,regional risk management,flight against drought and drought disaster alleviation strategies and framework study,and flight against drought-effectiveness analysis in Guangxi,in order to provide scientific basis and theoretical support for future drought disaster prevention and reduction in this region. |
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