Modeling Pol-InSAR Measurements of Vegetation Three-dimensional Structure at X-,L-,and P-Band.

Shadi Oveisgharan, JPL, shadi.oveisgharan@jpl.nasa.gov (Presenter)
Sassan Saatchi, CALTECH/JPL, sassan.saatchi@jpl.nasa.gov

Estimation of forest height from combined interferometric and polarimetric synthetic aperture radar (Pol-InSAR) measurements has been the focus of radar remote sensing studies in the past decade. Forest height is a critical indicator of forest successional stage and is used in quantifying the distribution of forest biomass. However, the estimation of forest height from Pol-InSAR depends on several factors such as the radar wavelength, the geometry of measurements, spatial heterogeneity of forest structure, and environmental variables (wind and moisture). Understanding these factors and quantifying their effects on the measurements and estimation algorithms require an accurate formulation of scattering mechanisms within the three-dimensional heterogeneous forest canopies over complex terrains. Pol-InSAR measurements of vegetation performed at low microwave frequencies (X-, L-, and P-band) allow global observations regardless of cloud cover and atmospheric condition, resolutions of meters to tens of meters to capture the spatial variability of forest structure. Penetration into the forest canopy improves as wavelength increases, and L-band and P-band have shown particular promise with regard to vegetation parameter estimation (Siqueira et al., 2008). In this study, we present a physically based model to simulate the Pol-InSAR measurements at these three frequencies. The model is based on electromagnetic wave theory and the distorted born approximation and the forest canopy is represented by a layer of discrete randomly distributed dielectric scatterers (e.g. leaves, branches, and stems) with vertical and horizontal heterogeneity over a rough soil surface. The interferometric cross- correlation is formulated from three dominant scattering mechanisms of volume, surface-volume interaction, and surface scattering from the forest floor. The model is finally used to simulate and discuss the impacts of measurement geometry (baseline, incidence angle) and forest structure and moisture on Pol-InSAR measurements over a temperate forest at X-,L-, and P-Band.

Presentation Type:  Poster

Session:  Other   (Wed 10:00 AM)

Associated Project(s): 

• Related Activity

Poster Location ID: 236