Poyang Lake Wetland Plants Microwave Scattering Characteristics Research and Biomass Inversion

Poyang Lake, which has a high level of biomass, is the largest freshwater lake in China with an area of about 3,000km². Its wetland ecosystem has a significant impact on China´s environment change. In order to investigate the biomass information of Poyang Lake wetland plants, the characteristics of wetland plants must be researched firstly. The MIMICS (Michigan Microwave Canopy Scattering) forest backscattering model was modified to accommodate the two scattering components of wetland plants. Using GoogleEarth as one of the references, a reasonable field sampling route was planned and carried out during from 2007-3-29 to 2007-4-3. Thus we can calculate the backscattering coefficient in MIMICS model using surveyed data. By analyzing of the output, it is found that height, gravimetric moisture content and leaf number density are the main three factors dominating the backscattering coefficients, in other words, the major scattering is from crown directly. At last, ANN (Artificial Neural Networks) method was used to retrieve the biomass information of Poyang Lake wetland. The biomass is 1.06 times 10⁹kg in April, 2007.