Remotely sensed estimate of biomass carbon stocks in Xilingol grassland using MODIS NDVI data

Accurate estimate of grassland biomass carbon stock is very important to carbon cycling and rational utilization of grassland resources. The natural ecosystem of Xilingol grassland has traditionally been the source of the most productive and highest quality grass in northern China. Based on the plant growing season MODIS-NDVI and Meteorological data, the present study employed the CASA model and plants withered loss model to estimate the above-ground carbon stocks of Xilingol grassland in 2002, 2005, 2009, and further calculate the below-ground biomass carbon stock according to the proportion of above-ground and under-ground biomass. The validation result indicates that the model achieved the reasonable results with an accuracy of 92.47%. Generally, the biomass carbon stocks in Xilingol grassland experienced a decreasing trend from 2002 to 2009., with a total carbon stock of 8.68, 8.09 and 7.61Tg (1Tg=1×1012g) in 2002, 2005, and 2009, respectively, and the corresponding below-ground biomass carbon stock was 40.64, 37.48 and 36.04Tg in three study years, which is approximately five times about the above-ground.