The quantitative estimation of periurban vegetation ecology using hyperspectral remote sensing

The environment of the mountainous area is one of important parts in urban ecological and economic system. It has an impact on the stabilization of urban ecological environment. Mentougou District in Beijing, a mountainous area, had abundant mineral resources originally. Many years´ exploitation activities made the mineral resources exhausted. It is an inevitable objective law that each mining site has to face. Of course, we know that it brought enormous benefits for the local government and the mine group, while it also had caused tremendous environmental damage. In order to realize the periurban ecological barrier of Beijing, the damaged ecosystem must be restored and the rapid succession of the architecture of plant community should be finished successfully. The paper took the Wangpingcun coal mine as a case study, the estimation models of the biophysical and biochemical parameters of vegetation were established by hyperspectral remote sensing technology. The fresh weight estimation model of vegetation was built based on the vegetation index of R752/R548 by thrice function method. The estimation model of chlorophyll concentration (SPAD) was established through linear four-point interpolation technique. The total nitrogen content estimation model was created based on derivative spectrum among the absorption bands ranging from 350 nm to 2500 nm through the multivariate regression modelling. Based on the construction of above models, the spatial distribution maps of biophysical and biochemical parameters of vegetation were extracted by the parameter mapping and regularities of distribution were revealed. The research results showed that the precisions of above estimation models were very high. The multiple determinant coefficients (R²) of fresh weight and SPAD and the total nitrogen content estimation models of vegetation were 0.883, 0.814 and 0.795 respectively. The spatial distribution maps indicated that the chlorophyll concentration and fresh weight - of vegetation around the coal wastes pile were the minimum. The more the SPAD and fresh weight became, the farther the distance away from the coal wastes pile became. The regularity of distribution of the total nitrogen content was completely opposite to the fresh weight and SPAD. It is concluded that estimating biophysical and biochemical parameters of vegetation using hyperspectral remote sensing is completely possible. It has theoretical significance for restoring service function of ecosystem and transforming regional industrial structure.