正态云模型在皖江地区土地生态安全评价中的应用

Application of normal cloud model on the comprehensive assessment of land eco-security in Wanjiang district

为了对皖江地区土地生态安全程度进行综合评价,解决土地生态安全评价中模糊性和随机性共存的问题,将正态云模型应用于皖江地区土地安全评价研究中。选取人口密度、人均耕地面积、单位面积耕地农药负荷、人均水资源量等17个指标,构建皖江地区土地生态安全指标体系,采用熵值法对各指标赋权,利用正态云模型的3个数学特征定量刻画各指标条件下的待评价城市的土地安全等级,借助云隶属度描述评价等级的模糊性,采用超熵概念刻画隶属度本身存在的随机性,最后通过集成变换,得到皖江地区9个市的土地生态安全等级。基于正态云模型综合评价的结果表明:皖江地区土地生态安全程度整体上属于中等偏上,其中滁州、合肥、宣城处于安全级,只有马鞍山处于极不安全级。

In order to evaluate land eco-security of nine cities in Wanjiang district, a comprehensive assessment method on the normal cloud model is suggested. Firstly, assessment index system is constructed, and land eco-security grade is described through single index for each districts. Secondly, each index weight is calculated by entropy weight method, and each eco-security grade evaluated by corresponding indexes is described using three mathematical characteristics of the normal cloud model. Thirdly, according to each assessment index, matrix of membership cloud model for each grade is determined using positive cloud generator, then, the fuzzy transformation subset is obtained based on the weights and membership degree matrix. Finally, the biggest membership degree is chosen as the result of comprehensive evaluation, and all results are compared with that of by entropy weight and matter element model. The results show that the land eco-security of Chuzhou, Hefei, Xuancheng are in safe grade, Wuhu, Tongling, Chaohu in relative safe grade, Anqing in critical safe grade, Chizhou in less safe grade, and Ma＇anshan in high safe grade. Therefore, the land eco-security grade of nine cities in Wanjiang district belongs to the average level on the whole, which is most consistent with the result assessed by matter element model.