Spatial-temporal variations of NDVI and its response to climate in China from 2001 to 2020

Vegetation plays an important role in global or regional environmental change. In this study, the spatial-temporal variations of NDVI and its response to climate in China and its seven sub-regions were investigated based on MODIS NDVI data, ERAS-land precipitation (PRE) and temperature (TEM) data from 2001 to 2020. The inter-annual growth rate of NDVI in China was 0.0021/yr in the past 20 years. The inter-annual growth rates of NDVI in seven sub-regions had significant differences at regional or seasonal scales. The ratio of improved vegetation area to the total studied area reached about 70%. In summer, vegetation degradation was concentrated in East China and Southwest China. The vegetation in Central China and South China improved more obviously in autumn than in the other seasons. The vegetation of Northeast China had a remarkable degradation in autumn and winter, especially in winter. The influence degree of PRE (q = 0.54, P < 0.01) was greater than that of TEM (q = 0.27, P < 0.01) in the control of the spatial distribution of NDVI. The interaction influence degree q of PRE boolean AND TEM was about 0.71 in the last 20 years. However, the PRE and TEM played different roles in vegetation growth in seven sub-regions.