Vegetation Net Primary Productivity Estimates, And The Relationship Between The Level Of Urbanization

Estimate of NPP is the basis and main content of carbon cycle research. On the basis of the Vegetation Classification of SPOT5 remote sensing image,Remote sensing estimation of vegetation NPP of parts of Shanghai in June 2005 was realized.The estimate made use of CASA model,weather and other ground data. The thesis has analysised the relationship between NPP and the level of urbanization and NPP of various land cover types in various regions.Finally, the study put forward advice for the sustainable development plan of Shanghai .In this paper, the research work and conclusions are as follows:(1)The FLAASH and 6S are used as the atmospheric correction models.In order to evaluate and validate the correction results, The object spectral reponse curve and NDVI profile curve were used to analyse the images after atmospheric correction.As a result, the FLAASH atmospheric correction model is better to SPOT5 remote sensing images than 6S model.(2) The land cover information was extracted from the study area making use of the support vector machine classification and maximum likelihood classification. Evaluating the classification results of two methods evaluate, the results show that the accuracy of Support vector machine classification is higher and the phenomenon of surface features misclassification is less.(3)According to NPP density distribution map, High value of NPP is in the various regions of the study area. Generally, the probability of high value appears relatively low in urban area, and the probability of high-value appeared relatively high in Pudong, Nanhui, Fengxian, Jinshan and other suburbs. The phenomenon consistent with the facts that woodland and farmland are less in urban, and woodland and agricultural land are relatively more.(4) NPP is closely related to the level of urbanization.With the level of urbanization increased, NPP is decreased. NPP of different land cover types are comparatively analyzed in each region.The results show that the forest NPP is the largest;carbon sequestration capacity is the highest, followed by grassland, and cropland carbon sequestration capacity is relatively low.