Spatial-temporal variation of NPP of vegetation in Xuzhou city based on TM data

Vegetation net primary productivity (NPP) has a great impact on terrestrial carbon cycle, which is an important index to determine the size of vegetation productivity and regulate ecological processes. In this paper, the urban with high spatial heterogeneity was selected as the research background, and the urban vegetation of Xuzhou was selected as the research object, then Landsat remote sensing images were used to estimate the net primary productivity of urban vegetation. First, the remote sensing image data were used to calculate the Normalized Difference Vegetation Index (NDVI) of Xuzhou, then LAI was calculated with the empirical model and NPP was further calculated to study the spatial-temporal distribution of NPP in Xuzhou from 2006 to 2016. Finally, combined with slope method, the variation trend of Xuzhou NPP was analyzed. The results showed that there was a significant improvement in the NPP in the eastern part of Xuzhou, while the central and western regions had a decreasing trend. So that the result can provide the planning basis for ecological garden city construction of Xuzhou.