Remote Sensing Monitoring Of Surface Ecological Disturbance In Ionic Rare Earths Mining Area Based On Temperature Differentiation

The application of ionic rare earths is extremely extensive.It has made significant contributions to China's economic development and it is an extremely important strategic resource for China.Because of the disorder management,excessive competition and excessive profit of rare earth industry,the activity of plundering rare earth was rampant and rare earth was over-exploited in some places,which has brought severe surface ecological disturbance and social problems to the local people.Based on above situation,the Lingbei ionic rare earth mining area in Ganzhou district as the study area was chosen in this paper,and the Landsat series satellite images were taken as the main data sources.The land surface temperature(LST)of the ionic rare earths could be obtained by inversion using the four equations: Artis algorithm,single channel algorithm,mono-window algorithm and radiative transfer equation.The paper compared and analyzed the separability and accuracy of those four algorithms for retrieving the LST of rare earth mining area objects,the best inversion algorithm of ionic rare earth mining area LST could be selected.The response relationship between temperature difference index(TDI)and vegetation index with surface ecological disturbance in rare earth the mining area were analyzed and compared.A better indicative factor of surface ecological disturbance could be selected.A general relational model which could represent the surface ecological disturbance of rare earth mining area was constructed based on selected indicative factor.And this model could be used to study the multiple temporal and spatial surface ecological disturbance in ionic rare earth mining area from 1991 a,2000a,2009 a and 2014 a.The results of the study are as follows:(1)The difference between the maximum temperature and the lowest temperature of the ionic rare earth mining area is very large in those four algorithms.In 2009 year,these regions of middle temperature and high temperature in LST and brightness temperature(BT)map in the rare earth mining area were inversed with the four algorithms,were mainly interpreted as the tailings produced by the rare earth mining,the situ leaching vegetation,the orchard and the farmland in historically Google Earth high resolution remote sensing image,which shows that rare earth mining activities and human activities lead to temperature anomalies in the mining area.(2)The objects' LST in rare earth mining area inversed by the mono-window algorithm has a separability index of 3.86662,which the separability index is the largest among those four algorithms.And the objects' LST of the ionic rare earth mining area inversed by this method showed the best separability.The difference between the average LST inversed by mono-window algorithm and the statistical average temperature of MODIS in rare earth mining area is only 0.24 K,which it is the highest accuracy of the above four algorithms.Considering the separability and accuracy of the objects' LST in the mining area,the mono-window algorithm is the best temperature inversion algorithm in the rare earth mining area.(3)Compared with the vegetation index,the TDI has obvious advantages in reflecting the surface ecological disturbance in the rare earth mining area.And it could better monitor the most intensely disturbed areas of the rare earth mining area which are tailings and in-situ leaching vegetation.At the same time,for human activities related to farmland,orchards,and reclaimed vegetation,such as the stronger surface ecological disturbance areas subjectively operated by humans could be better identify with the TDI.Compared with 1991 a,the mining scale of 2000 a rare earth mining area has been greatly reduced.The work of closing mountains and cultivating forests and reclaiming vegetation on the ground of dumping tailings has been actively promoted.The ecological environment of ionic rare earth mining area has been improved to a large extent.After 2000,the continuous expansion of the scale of rare Earth mining and the gradual popularization of in-situ leaching process in the mining area,which made the area of temperature difference degree(TDD)of heavier and severe grades increase continuously.The distribution of severe grade patches in the TDD map changed from aggregation to fragmentation.And it continuously spreads to the entire rare earth mining area,so that the restoration and governance in rare earth mining area become more difficult.