| As an important part of the global ecosystem,vegetation not only plays a key role in soil nutrient loss,wind-sand activity,hydrological erosion,and material migration,but also serves as an indicator of sensitive indicators in the environment.As an indicator of the ecological environment,the vegetation index can indicate the changing trend of the ecological environment.Shanxi Province is rich in coal resources,and long-term coal development and utilization has caused ecological and environmental problems such as surface vegetation degradation.Combining the current research progress and practical needs,understanding the temporal and spatial changes of vegetation in Shanxi Province and the analysis of influencing factors can provide a theoretical basis for the government and the ecological environment departments to make ecological environment-related decisions,which is of great significance.This article first takes Shanxi Province as the research area,uses MODIS13Q1 data from2001 to 2020 to obtain two vegetation index remote sensing images,NDVI and EVI,and analyzes the inter-annual,inter-seasonal,and inter-monthly three images of Shanxi Province through the pixel-by-pixel linear regression analysis method.The temporal and spatial distribution of the two vegetation indices on three scales;combined with meteorological factors such as temperature and precipitation,as well as terrain factors such as altitude,slope,and aspect,analyze the correlation between vegetation indices and meteorological factors and terrain factors.Finally,taking the Xishan coal field as an example,through the establishment of ecological verification areas,the vegetation index of each area is compared and analyzed by division and classification to explore the degree of influence of mining activities on the vegetation index of the mining area.Research shows that:(1)The vegetation index of Shanxi Province is on the increase from 2001 to 2020.From a spatial perspective,except for the north and west,the vegetation index of the rest of the region is relatively high.The vegetation index of the mountainous areas of the Lvliang Mountains and Taihang Mountains is relatively high,and the vegetation index of the middle basin is relatively low;from the perspective of inter-annual changes,the annual growth rate of vegetation is 0.005/a,and the overall trend is increasing;from the perspective of seasonal changes,The vegetation index has the largest value in summer,followed by autumn.The value of spring is smaller than that of summer and autumn,and the smallest in winter.From the perspective of inter-month changes,the growth pattern of vegetation index shows certain phenological characteristics.The maximum value is in August,and the minimum value is in January.(2)The change of vegetation index is affected by the two meteorological factors of temperature and precipitation,but in general it has a greater correlation with precipitation;the vegetation index of Shanxi Province shows an increasing trend with the increase in altitude,in the range of 2111-3054 m.The internal vegetation index reaches the highest value;the vegetation index is the highest in the area with a slope of 45°~79°;at the same time,the vegetation index does not change significantly with the slope direction.(3)From 2001 to 2020,both the vegetation index of the Xishan coal field and the verification area showed an increasing trend,and the farther the study area is from the mining area,the more obvious the increase in the vegetation index;the vegetation growth rate of the Xishan coal field was 16.77%,and the verification area was 22.30%.The growth rate of vegetation in Xishan coal field is-5.53% relative to natural ecological conditions;the mining area and surrounding ecological environment is affected by mining disturbance factors and is related to the distance from the mining area.Generally,the longer the distance,the greater the vegetation index and the greater the stability.Stronger,the less affected. |
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