Monitoring model of aboveground biomass in Gannan grassland based on remote sensing

In this paper, using 16 days 250m MODIS vegetation index dataset, the relationship between eight vegetation indexes (Vis) and aboveground biomass in Gannan grassland of China, was analyzed. Based on their correlations, monitoring models of aboveground biomass was constructed, and then the aboveground biomass of the whole Gannan Autonomous Region and its every county were estimated. The results showed that in most growth period, there are very significant relativity between vegetation indexes and aboveground biomass, which is the most obvious with synchronous EVI(r=0.782). And the cubic polynomial model of EVI fits aboveground biomass better than other vegetation indexes and functions. Based on above formula, aboveground biomass of Gannan grassland in 2007 and 2008 are separately 5610kg/hm² and 5605kg/hm². As to every county, comparing with that in 2007, aboveground biomass of 2008 in Lintan, Zhuoni and Diebu County increased, while in Hezuo, Maqu, Luqu, Xiahe and Zhouqu County it decreased.