Analysis of Spatial-temporal Variation Characteristics of Vegetation in the Yellow River Source Region from 1982 to 2019

As an important component of surface cover, the changes of vegetation can reflect the changes of regional environment at different spatial and temporal scales, and the normalized difference vegetation index (NDVI) based on remote sensing can effectively reflect the growth status of surface vegetation, and the study of the spatial and temporal characteristics of NDVI changes of vegetation in long time series can help the protection and sustainable development of regional ecological environment. In this study, based on the overlapping period data of Global Inventory Modeling and Mapping Studies (GIMMS) NDVI from 1982 to 2015 and Moderate-resolution Imaging Spectroradiometer (MODIS) NDVI from 2000 to 2019 in the Yellow River source region (YRSR), we established the GIMMS NDVI dataset from 1982 to 2019 in the YRSR, and analyzed the spatial and temporal characteristics of vegetation NDVI changes in the YRSR for 38 years by using linear regression analysis, accumulative anomaly method and moving ttest method. The results showed that the spatial distribution of NDVI in the YRSR was high in the southeast and low in the northwest, and the spatial trend was increasing in the north and decreasing in the center. The mean NDVI from 1982 to 2019 showed an overall weak increasing trend, with abrupt changes in NDVI in 2000 and 2008. This study will contribute to a better understanding of the vegetation cover changes in the YRSR, which is of great significance for the ecological protection of the YRSR.