Abstract:

Quantitative RSIM (Remote Sensing Information Model)was improved to evaluate the desertification degrees by using the data of state produced hyperspectral resolution imagining spectrometer, and the mainly quantitative factors on desertification assessment were retrieved which including the vegetation cover, the biomass and the soil water content. For the indexes which are difficult to count, the recoding maps based on the visual interpretation are obtained and then imaged respectively to be used in the RSIM. Every pixel in image can be used to acquire the indexes of all the evaluative factors. Based on the current methods on desertification assessment, quantitative RSIM on the basis of the pixel is developed and the distributing map of desertification degree is plotted in this paper. The result shows that it is relied to retrieve quantitatively the vegetation cover, the biomass and the soil water content of the desert area by the data of hyperspectral resolution imagining spectrometer, when there are both the shrub and the grassland in the retrieved region, the precision of the polynomial model is obvious higher than that of the linear model, contrastingly when the type of the vegetations is simplification, the linear model has the higher precision but limited applied range and can only be applied in block. So the retrieval efficiency can be improved by using the polynomial model in the region having only the shrub and the grassland. The method retrieving the soil water content is suitable to the flat area with sparse vegetations, at the same time the research shows that the model based on the soil thermal inertia stands against the interference of vegetations. On the whole, the precision of the desertification assessment RSIM lies on the data acquired precision and the current methods on desertification assessment that is to say whether the appraisable indexes are rationale and scientific or not and whether the weigh and the grade criteria that the experts give are objective or not.

Key words: Hyperspectral resolution, Desertification assessment, Remote Sensing Information Model