The Variability of NDVI over northwest China and its relation to temperature and precipitation

Abstract

Land vegetation plays a major role in the global climate change through carbon cycle, and climate change in turn affects vegetation growth and its photosynthetic activity. In arid and semi-arid area, sparse vegetation cover characterizes environments. Thus quantitative temporal series analysis of vegetation distribution and its variations enables observing annual trends, helps to find out the reason for environment variability. There are serious environmental problems, such as deforestation, soil erosion, salinization, and desert encroachment in the northwestern China, its natural conditions is very delicate. In this paper, we built the time series of vegetation change by the NDVI (normalized difference vegetation index) covered northwest regions in recent 19 years, and analyze the time serial NDVI variability using three methods, which are simple differencing, slope map of NDVI, slope map of biomass. The correlation analysis between NDVI with the temperature and precipitation in northwestern China was carried out. The results showed that there was significant positive correlation between NDVI and precipitation, and temperature was not strong correlation relatively with NDVI in the northwest China.