Estimation of terrestrial net primary production and its temporalspatial distribution in Henan Province based on GIS and RS

On the basis on data from the ground meteorological station and remote sensing, and differences in maximum light utilization efficiency, the CASA mode was used to estimate the net primary production (NPP) by the ARCGIS 9.2 and ENVI 4.5 in Henan Province, China. The results of this study showed that NPP in Henan Province was 34.87 Mt C, and its spatial distribution was closely related to vegetation type, indicating that NPP of forest was the biggest, NPP of shrub came to the second, and NPP of grassland and cropland was the third and the fourth. NPP in December, January, and February was the lowest, accounting for 1.38% of annual NPP, and those in May, July, and August were was the biggest, which was 56.84% of annual NPP. Compared to Miami, Montreal, Chinkugo model, this study was similar to results from Miami, and order of vegetation types was similar to order from Chinkugo. This study suggested that the CASA mode predicted well the NPP in Henan Province, and was suitable for simulating the NPP.