Evaluation on Net Primary Productivity of Alpine Meadow Based on HJ-1Satellite Data:A case study in the Zoige Grassland

Based on HJ-1 satellite data,digital elevation model data,meteorological data and measured data in field,the net primary production(NPP) of the Zoige Grassland in 2010 was simulated by using the improved CASA model in order to assess the potential application of HJ-1 satellite data in NPP estimation in alpine grassland.The results showed that:(1) Comparison between the actual measured biomass and the grass biomass simulated by using the CASA model indicated that the correlation was higher,the simulation accuracy was more than 80%,and R2=0.8726.The CASA model could be used to estimate NPP in the Zoige Grassland.(2) Although the simulated NPP was greater than that acquired by the other researchers,the improved CASA model was more suitable in the Zoige Grassland.(3) HJ-1 satellites could offer the high time and high spatial resolution data sources for estimating NPP in alpine grassland.