Remote sensing based monitoring of interannual variations in vegetation activity in China from 1982 to 2009

Terrestrial vegetation is one of the most important components of the Earth＇s land surface. Variations in terrestrial vegetation directly impact the Earth system＇s balance of material and energy. This paper describes detected variations in vegetation activity at a national scale for China based on nearly 30 years of remote sensing data derived from NOAA/AVHRR（1982–2006） and MODIS（2001–2009）. Vegetation activity is analyzed for four regions covering agriculture, forests, grasslands, and China＇s Northwest region with sparse vegetation cover（including regions without vegetation）. Relationships between variations in vegetation activity and climate change as well as agricultural production are also explored. The results show that vegetation activity has generally increased across large areas, especially during the most recent decade. The variations in vegetation activity have been driven primarily by human factors, especially in the southern forest region and the Northwest region with sparse vegetation cover. The results further show that the variations in vegetation activity have influenced agricultural production, but with a certain time lag.