The sensitivity of near-infrared band to biomass decreases with the increase of vegetation density, while there is no significant change in red spectral reflectivity. Using SAR data to quantify the biomass usually suffers from the influence of soil humidity, surface conditions, especially those areas with low and middle biomass, resulting in the phenomenon that different biomass have the same or approximate total radar backscattering coefficient. In this paper, we have done research on the sensitivity to the biomass for three kinds of vegetation indices NDVI, RVI and DVI, and improved parameters of MIMICS model to simulate scattering components, setting up the simulation database of all backscattering components. And then we used Landsat TM and ENVISAT ASAR alternating polarization data with their reciprocal advantages, selecting the difference vegetation index DVI=0.45 as the threshold to divide the wetland plant into two parts. For DVI<0.45, we apply the statistical analysis methods to build a linear regression model with samples. For DVI>=0.45 the areas with high leaf density, it can be estimated by using C-band approximate microwave scattering models. Finally the entire wetland biomass of Poyang Lake is approximately 2.1×10⁹ kg.

Date Published: 3 November 2010
PDF: 10 pages
Proc. SPIE 7841, Sixth International Symposium on Digital Earth: Data Processing and Applications, 78411D (3 November 2010); doi: 10.1117/12.873263

Published in SPIE Proceedings Vol. 7841:
Sixth International Symposium on Digital Earth: Data Processing and Applications
Huadong Guo; Changlin Wang, Editor(s)