Dynamic Risk And Driving Force Of Agricultural Drought In Shaanxi Procince

Drought disaster seriously restricts the development of agricultural economy in Shaanxi Province,which is known as "nine droughts in ten years".Agricultural drought risk assessment is the basic work for scientifically customized drought mitigation strategies and measures.This paper uses principal component analysis to select evaluation indicators,uses analytic hierarchy process and improved entropy weight method to determine index weights,and constructs a comprehensive index assessment model for agricultural drought risk based on disaster risk theory.Dynamic risk assessment and driving force analysis of agricultural drought in Shaanxi Province were carried out.The main research results are as follows.(1)Two risk indicators,five exposure indicators,four vulnerability indicators and five adaptability indicators were selected through principal component analysis and combined with disaster risk theory.Based on the four elements of drought risk,the agricultural drought risk assessment index system of Shaanxi Province was established.(2)Through the correlation verification of grain yield per unit area and fruit yield per unit area series and the comprehensive evaluation index of agricultural drought risk calculated by the two methods,it is judged that the weight calculated by AHP is more consistent with the actual situation of this study.(3)The spatial and temporal characteristics of the four factor indexes and comprehensive indexes of dynamic risk assessment of agricultural drought in Shaanxi province were analyzed by AHP.The results showed that the spatial distribution of risk index was similar to that of natural environment.Except for the two cities in northern Shaanxi,the exposure index of other cities showed a downward trend,the vulnerability index of each city remained stable over time without fluctuation,and the adaptability index of each city in the whole province showed an upward trend.The fluctuation of agricultural drought risk composite index is affected by risk index.(4)Each factor index of each city was analyzed,and the degree of influence was sorted through the influence integral to determine the degree of influence of the four factors in each region;The factor contribution degree of each factor is calculated to determine the contribution degree of different indicators of each factor in different cities.Combining the influence degree of each city by the four factors and the index contribution degree of each factor,the corresponding drought resistance countermeasures are put forward.