Multi-scale Spatiotemporal Pattern Analysis And Prediction Of Non-ferrous Metal Industry Sites

In the past 40 years of reform and opening up,with the rapid development of China’s economy and industrialization,the demand for non-ferrous metals is strong,which makes the number of non-ferrous metal industrial sites increase substantially and the site scale expand considerably.Therefore,it is a potential threat to the environment around the site and the health of residents.Its risk is highly related to the control of enterprises and government departments due to the complex driving factors involved in non-ferrous metal site pollution.As a result,the spatiotemporal distribution of non-ferrous metal industrial sites and its formation mechanism are very complex.To study and summarize the spatiotemporal distribution characteristics and evolution mechanism of multiscale nonferrous metal industrial sites,and to predict their spatiotemporal distribution are helpful for enhancing the understanding of the spatiotemporal distribution law of non-ferrous metal industrial sites in China.It provides a paradigm for the study of the spatiotemporal distribution of other types of industrial sites in China and a reference for the development of various types of social and economic entities.This paper takes the country,Hunan Province,and Chenzhou City as the research areas to construct a multiscale non-ferrous metal industry site standard database,including site distribution data,environmental data,and socioeconomic data from 1990 to 2020.Taking the provincial scale as an example,based on existing studies,elevation,slope,aspect,number of ore deposits,distance from ore deposits,distance from development zones,distance from main roads,distance of protected areas,presence of development zones,changes in the level of economic development,changes in the level of industrialization,and changes in the proportion of industrial land are taken as the 12 independent variable factors.In this paper,the random forest model is used to reveal the driving effects of the above factors on the spatiotemporal pattern evolution of non-ferrous metal industrial sites in Hunan Province.Based on the time series trend model,the multivariable autoregressive model of policy superposition,and the maximum entropy–temporal regression ordinary Kriging model,the spatial distribution of the number and the probability of the presence of non-ferrous metal industrial sites in 2025 is predicted at the municipal administrative unit and grid unit scales,respectively.Research indicates the following:(1)In the past 30 years,the number of non-ferrous metal industrial sites at all scales increased remarkably.The growth rate was fast before 2010 and then slowed down.In addition,the evolution of distribution pattern has substantial directionality.The mining sites of non-ferrous metals in China are concentrated in Yunnan Province and Hunan Province,which are rich in non-ferrous metal resources,whereas the smelting sites are mainly distributed in Hunan Province and Jiangsu Province,which are subject to their resource dependence.The overall distribution of non-ferrous metal industrial sites in China has the characteristics of “more in the east and less in the west,” “faster in the east and slower in the west,” showing the evolution characteristics of spreading from the core provinces to the surrounding,and showing the trend of inland and northward center.The non-ferrous metal industrial sites in Hunan Province have formed the spatial distribution characteristics of“multicore and multisub,” with Chenzhou,Hengyang,and Xiangxi autonomous Prefecture as the core distribution areas,and Loudi,Yiyang,and Changsha East as the subcore distribution areas.The evolution direction is “southeast–northwest” and gradually dispersed from 2000 to 2010,showing a trend of “dispersion–aggregation–dispersion.”Most areas of Chenzhou City have non-ferrous metal industrial sites,among which Suxian District has the largest number of mining sites,and Yongxing County has the largest number of smelting sites.The mining sites show a trend of spreading from Suxian District and Linwu County to surrounding areas.The smelting sites form a distribution pattern of “one core and multiple units,” with the northern part of Yongxing County as the core,and the southeastern part of Guiyang County,the western part of Yongxing County,and the central and western parts of Zixing City as the secondary cores.(2)Location policy,population density,and economic development level are the main factors affecting the formation and evolution of non-ferrous metal industrial sites.Among them,location policy is the most important factor for site formation because relying on the background of urbanization,land use planning policies and preferential land tax policies have been formulated for industrial parks and development zones at all levels,attracting a large number of enterprises and factories to settle in.In addition,the most important goal of industrial site selection is to reduce production cost,and labor cost becomes the most important factor in site selection.Cheap,plentiful labor can bring enormous advantages to the operation of industrial sites.The level of economic development can also indirectly promote the formation of non-ferrous metal industrial sites,provide convenience and guarantee for the progress,upgrade,and development of the non-ferrous metal industry,and broaden the development space of China’s non-ferrous metal industry.(3)In this paper,the maximum entropy model is used to calculate the distribution probability of non-ferrous metal industrial sites in 2018.By using the time series model,multivariate autoregressive model based on policy superposition,and maximum entropy–temporal regression ordinary Kriging model,the number of municipal non-ferrous metal industrial sites and the probability of existence of non-ferrous metal industrial sites in the grid unit(Chenzhou city as the research area)in China are predicted.The results show that by 2025,the number of non-ferrous metal mining sites in most cities of China will be less than 50,the number of smelting sites will be less than 90,and the number of non-ferrous metal industrial sites in central Yunnan,southern Hunan,and southern Jiangxi will be more.In Hunan Province,608 and 335 sites are in Chenzhou and Xiangxi,respectively.Chenzhou and Hengyang have more smelting sites,544 and 302,respectively.As for the probability distribution of non-ferrous metal industrial sites in Chenzhou,compared with 2018,the overall probability of mining and smelting sites in Chenzhou will increase in 2025,and the high-probability areas are widely distributed.The high-probability areas of mining sites are mainly concentrated in Suxian District,Beihu District,Linwu County,and Yizhang County.The high-probability regional distribution of smelting sites is similar to that of mining sites,mainly concentrated in Suxian District,Linwu County,and Yongxing County.