Study On The Impact Range Of Coal Mining On Vegetation Based On Fourier Analysis

In recent years,with the rise of coal resources in the northwest arid desert area,the surface vegetation degradation and other problems caused by large-scale coal mining in Ningdong and Wuhai have had a huge impact on the ecological environment.In order to explore the impact of coal mining on the local environment To analyze the time series of vegetation index changes in Ningdong and Wuhai mining areas and the range of coal mining on the surrounding vegetation,which is conducive to provide a theoretical basis for the corresponding ecological protection work in the mining area.In this paper,the Ningdong mining area and the Wuhai mining area are used as research areas,and the reference area is set up at the same time.The spatial analysis of GIS is used to set up buffer zones with different distances and intervals.The MOD13Q1 remote sensing images from 2008 to 2017 are selected based on the normalized vegetation index.,Using the Fourier analysis method,and comparing with the vegetation in the reference area to analyze the time-series changes of the vegetation index of the mining area,through the Fourier fitting order results and combining the 2017 land use type statistical table to explore the impact of coal mining on the surrounding vegetation range.The main conclusions of this article are as follows:(1)Through the Fourier fitting of the NDVI time series of Ningdong and Wuhai mining areas from 2008 to 2017,it can be seen that the vegetation growth status of the mining area is well fitted,and the monthly NDVI value is obviously related to the phenological period of vegetation For the phenological correspondence,the vegetation index curve has a peak every year.The maximum value is mainly in August,partly in July and September,and the lowest value occurs in January or February.These are all related to the seasonal change of vegetation growth in the mining area.Correspondingly,and overall,the vegetation index of Ningdong mining area showed a trend of increasing volatility,while under the extensive coal mining method,the vegetation index of Wuhai mining area showed a trend of decreasing volatility.(2)Fourier fitting processing is also performed on the vegetation index of the reference area and compared with the Ningdong mining area.The overall vegetation growth status is better than that of the Ningdong mining area,it shows that the vegetation in the reference area without human interference is in good condition.This comparison shows once again the negative impact of human intervention such as coal mining on the regional vegetation and the positive impact of human activities such as ecological restoration of the mining area on the vegetation in the mining area.(3)By comparing the Fourier fitting order results of the Ningdong mining area and the reference area,it is found that the impact of coal mining on the regional vegetation in the Ningdong mining area is the area 6km away from the boundary of the mining area,and the vegetation within 3km is affected.The Ningdong mining area has the greatest impact.With the increase of the buffer zone distance,the mining impact of the surrounding vegetation is gradually weakening.The same analysis shows that the impact area of the Wuhai mining area includes the area of 5km around the boundary of the mining area,and is particularly affected by coal mining within 2km.Afterwards,the impact of vegetation in the buffer zone decreases as the distance increases.Combining the analysis of different land use types and the setting of the reference area provides a certain basis for the rationality and accuracy of the results of the impact of the mining area on the surrounding vegetation.