Comparison of NPP estimation by remote sensing-based parametric model and ecological processed model over forest at regional scale

This study compared remote sensing based method and ecological process model (Biome-BGC) to characterize Fujian forest ecosystems in terms of net primary productivity (NPP). The results of Biome-BGC model showed that the annual mean NPP of Fujian´s forest ecosystem was 759.63 g C m^-2 a^-1 from 1991 to 2005, the average total NPP for the same period was 2.04×10⁸ g C a^-1. Driven by MODIS data in 2005 and corresponding spatial weather data yield by spatial interpolation, this study estimated NPP of Fujian´s forest ecosystems in 2005 was 818.585 g C m^-2 a^-1, total NPP was 2.19×10⁸ g C a^-1, and there were two significant peaks of NPP during the year. The estimations of the two models agreed on the NPP of Fujian´ forest ecosystem in 2005 both spatially and quantitatively, and their estimates of NPP agreed quite well with those reported by previous investigators which was summarized from direct field measurements in subtropical forest ecosystems. There were obvious regional variations in the distribution of NPP, with higher NPP in the two mountains areas of Fujian province where elevation is relative high and little influence by anthropogenic activities.