NPP Estimation of Wuhan Area Using Landsat Data: Changes between 1988 and 2002

Industrial development and human activities have greatly altered land cover over the past several decades. To measure net primary production (NPP) is a way to understand the photosynthesis capabilities of the vegetation. Great progress was made in the study of zonal NPP estimation, especially in world wide or in China; however, quantitative research on NPP at the regional scale using multi-temporal satellite data is still inadequate. In this study, Wuhan city of Hubei Province, China, was chosen as the study area.17 scenes of Land sat images were used to estimate annual NPP of 1988 and 2002 using photosynthesis curve model with vegetation index based on universal pattern decomposition method (VIUPD). NPP of Wuhan area in 1988 was estimated to be 2.64times10-3PgC/a, and average NPP was 356.76gC/m2/a; where NPP in 2002 was estimated as 2.52times10-3PgC/a, and average NPP was 341.17 gC/m2/a. Although NPP of China increases 0.6973 PgC from 1982 to 2000 with the speed of 0.0367 PgC per year, NPP of Wuhan decreased. It was found because of speeding up urbanization of Wuhan for these twenty years by spatial-temporal patterns analysis.