GEE-based NDVI in Beijing Analysis of Temporal and Spatial Changes

Ziyu Zhang
School of Information Engineering,China University of Geosciences Beijing, Beijing100000, Beijing, China

Abstract:

Based on the Google Earth Engine (GEE) platform, the average NDVI values of Beijing were calculated for every 4-year interval from 2000 to 2020, and the spatial and temporal changes of the vegetation cover in Beijing were quantitatively analyzed by using a combination of significance test and trend analysis. The analysis shows that: the annual average NDVI in Beijing increases steadily and gradually, the national vegetation protection policy for semi-arid areas has obvious effects, and the vegetation ecology shows an improving trend; the annual average NDVI index in Beijing shows the characteristics of high in the surrounding area and low in the middle, and the high value area gradually expands from the west and the north to the east and the south; the increased area of the NDVI is larger than the degraded area, and the significantly rising area is larger than the significantly decreasing area, so the overall condition of the vegetation cover in Beijing shows an improvement and restoration. NDVI increased more than the degraded area, and the significantly increased area was greater than the significantly decreased area, so the vegetation cover condition in Beijing showed an overall trend of improvement and recovery.