The change of NDVI time series based on change vector analysis in China

Change vector analysis (CVA) in NDVI time-trajectories space is a powerful tool to analyze land-cover change. The magnitude of the change vector indicates the amplitude of the change, while its direction indicates the nature of the change. CVA is applied to two remotely sensed indicators of land surface conditions, NDVI and spatial structure, in order to improve the capability to detect and categorize land-cover change. The magnitude and type of changes are calculated in China from 1989 to 1999. Through the research, the main conclusions are: 1) the change of NDVI is very different between east China and west China, and change scope in the east is bigger than in the west. The trend in NDVI time series is a smooth increase, the increases happened mostly in Taiwan, Fujian, Sichuan, Henan province and the decreases are located in Yunnan, Xinjiang province. 2) The spatial structure indicator is able to detect changes in the seasonal ecosystem dynamic for spatially heterogeneous landscapes. Most of spatial structure changes, which occurred in South China, correlated with vegetation growth processes and the directions of strike of the mountains