Aboveground Biomass Inversion of Grassland in Ili Area Using MODIS Data

The basic data involved the observed data of aboveground biomass from July to August in 2012 in Ili as well as the MODIS data during this period,and the purpose of this study was to protect and utilize grassland resources reasonably.The correlation relationships among enhanced vegetation index(EVI),normalized difference vegetation index(NDVI) and observed data of aboveground biomass were analyzed by linear regression model,quadratic polynomial regression model and index regression model.The spatial distribution of aboveground biomass in the grassland of Ili was simulated and analyzed.The results showed that a significant correlation relationship existed between vegetation index and aboveground biomass,while the quadratic polynomial regression model based on EVI(y=14759~x2- 4758 x + 1346.2,R~2=0.8402)was the most suitable one,and estimation accuracy was 92.19%.The dry weight per unit area in the grassland of Ili was 1817 kg·hm~(-2),and the total yield was 70.59×10~8 kg in 2012.Along with the increasing elevation,aboveground biomass increased first and then decreased.