Analysis of Spatial and Temporal Variations of Vegetation Index Based on the GEE Platform——Take Hangzhou Bay of Ningbo as an Example
In order to determine the space-time characteristics of vegetation growing,aiming at the problems of poor efficiency in remote sensing information extraction of traditional methods,based on the Google Earth Engine (GEE) platform,NDVI data was extracted using Landsat image in the growing season from 1990 to 2020,and the space-time characteristics of vegetation were discussed with unitary linearity regression. The results showed that,1) In the past 30 years,the surface vegetation coverage in Ningbo-Hangzhou Bay has changed little,the proportion remains at around 85％. However,the proportion of medium and high vegetation coverage ( 0. 6<NDVI<0. 8) decreased by 67％,mainly transformed into low coverage (0. 2<NDVI<0. 4) and medium coverage (0. 4<NDVI<0. 6). Since 2015,the proportion of protected areas and coastal tidal flats with high vegetation coverage ( 0. 8<NDVI<1) has increased;2) The spatial distribution of NDVI in the study ar-ea has obvious differences,from land to sea,medium and high vegetation coverage showed a trend of the first decrease and then increase. Some high vegetation coverage was distributed along the tidal flat,mainly the Spartina alterniflora community,and its distribution was greatly affected by human reclamation activities. As an important quantitative factor,NDVI can provide basic data for the evaluation of environmental carrying capacity and ecological restoration.
NDVIHangzhou Bay of NingboGEEspatiotemporal variation
NETL
NSTL
万方数据
