Grey Cluster Evaluation Of Agricultural Drought Vulnerability In Henan Province

Drought is one of the natural disasters that seriously restrict agricultural development.In the field of disaster science,the degree of drought risk is directly proportional to vulnerability.Scientific assessment of agricultural drought vulnerability is of great significance to agricultural drought risk management.Henan Province is a big grain province in China,but with the global climate change,the drought problem in Henan Province is becoming more and more serious.Therefore,a reasonable evaluation of agricultural drought vulnerability in Henan Province can provide theoretical basis for drought prevention and disaster reduction in Henan Province.Considering that the occurrence of drought is gradual,grey uncertainty and randomness,the grey C-type correlation model and normal grey cloud clustering evaluation model based on panel data are constructed and applied to the assessment of agricultural drought vulnerability in Henan Province.The specific contents are as follows:(1)Taking Henan Province as the research object,combined with the actual situation in the study area,13 indicators,such as multiple cropping index,fertilizer application amount per unit area,agricultural GDP ratio and total power of agricultural machinery,were selected to construct an index system.Based on the data of Henan Province from 2013 to 2018 in recent years,the indicators were explained,the weights of indicators were determined by entropy method,and the vulnerability assessment model of agricultural drought was constructed by weighted synthesis method.The model is used to comprehensively evaluate the drought vulnerability in Henan Province,which provides certain decision support for the implementation of drought relief work.(2)Drought is gradual,so it is more practical to consider drought based on three dimensions: index,sample and time.To solve the problem that the existing evaluation models can not fully integrate time elements,taking the representation of panel data matrix as a starting point,the displacement correlation degree,velocity correlation degree and acceleration correlation degree of behavior matrix are calculated by exponential function,and a grey C-type correlation model based on panel data is constructed.Comparative analysis shows that the model is simple and effective,and is not affected by the order of samples.Applying the model to the analysis of agricultural drought vulnerability index in Henan Province has certain reference value for the implementation of drought prevention and control work.(3)The occurrence of drought has great randomness and grey uncertainty.In view of the problem that the existing drought vulnerability assessment model can not reflect these characteristics at the same time,the normal grey cloud is introduced into the whitening weight function,and the cluster assessment model of normal grey cloud is constructed based on the analysis results of drought vulnerability index.The cluster analysis of agricultural drought vulnerability in 18 areas of Henan Province is carried out by using this model,which provides a theoretical basis for drought prevention and disaster reduction in Henan Province.