Research on the spatiotemporal evolution characteristics of NDVI in Shendong mining area based on GEE long-time series remote sensing images

The study on the spatiotemporal evolution characteristics of NDVI in Shendong mining area, conducted using long-time series remote sensing images from Google Earth Engine (GEE), holds significant value for ecological protection and sustainable development of mining areas. By analyzing the NDVI data from the period of 1986 to 2024, the research reveals a fluctuating growth trend in the overall surface vegetation.

The mean annual NDVI increased by 0.14 with an increase rate of 0.0036 per year, indicating a 54.46% rise over the 39-year period, and an average annual growth rate of 3.18%. The coefficient of determination (R) of the linear fitting equation reached 0.8975, further emphasizing the significant positive trend in surface vegetation.

Upon examining the 18 coal mines within the Shendong mining area, the research finds that their annual average NDVI also exhibited a clear fluctuating growth trend. The correlation coefficients (R) for each mine ranged from 0.8188 (Wujiata) to 0.9118 (Cuncaota), with the overall trends being largely similar across the mines. This suggests that the vegetation coverage and quality have been positively influenced by the presence of these coal mines.

The analysis of NDVI mean evolution trends in the Shendong mining area reveals a normal distribution pattern, characterized by strong spatial heterogeneity. The study finds that 55.38% of the area showed no significant change, 5.42% experienced extremely significant reduction, and 6.69% displayed extremely significant increase. Specifically, the regions of least significant change mainly comprise construction land and open-pit mining, while water bodies, forest land, and valley land are the primary areas of substantial increase.

This distribution pattern reflects the complex interplay between ecological restoration efforts and mining disturbances.

The research also highlights the extreme and uniformity of the spatiotemporal distribution characteristics of NDVI in the Shendong mining area over the 39-year period. The first principal component (EOF1) of the EOF analysis can represent the entire NDVI change trend in the entire Shendong mining area, exhibiting a "medium coverage as the main, high coverage as the supplement" pattern. This pattern underscores the balance between ecological restoration and mining impacts in the region.