Multiple Scattering Effects With Cyclical Correction in Active Remote Sensing of Vegetated Surface Using Vector Radiative Transfer Theory

Modelling and Validation of Combined Active and Passive Microwave Remote Sensing of Agricultural Vegetation at L-Band

“…The consistent combined active and passive model based on NMM3D-DBA adopts a single scattering model for vegetation; it has been shown to be able to provide good estimations for backscatter and brightness temperature at L-band for wheat, winter wheat, pasture, and canola fields. As the frequency increases, multiple scattering effects in vegetation become more important [26]. Thus, at frequencies much higher than L-band, a multiple scattering approach should be used for vegetation instead of the distorted Born approximation.…”

“…Collective scattering effects of the vegetation scatterers are important for the soybean [38], thus a more accurate coherent model must be used for this vegetation type. For the corn field, multiple scattering effects [26] must be included because of the large scattering albedo and optical thickness. These two vegetation types and more accurate scattering models for higher frequencies will be studied in the future.…”

“…The leaf thickness is much smaller than the wavelength at L-band, and thus the total area of the leave is more important than its shape [26]. Similar to the pasture and wheat case, these elements are assumed to be uniformly distributed in the canola layer with different orientations.…”

“…The collective and multiple scattering effects do not contribute significantly for the fields studied in the paper since bistatic surface scattering mostly dominates among the three scattering mechanisms and the scattering parameter ω as well as the optical thickness τ is not large for these fields. Thus the distorted Born approximation which is easier to implement and requires less input parameters than the coherent model [21] and the multiple scattering model [26] is applied to these fields. The model results are compared with the brightness temperature and backscatter observations from SMAPVEX12 [14].…”

A Generic First-Order Radiative Transfer Modelling Approach for the Inversion of Soil and Vegetation Parameters from Scatterometer Observations

“…Theoretical models that estimate ω from assumptions on geometrical and dielectrical properties of the vegetation-constituents usually obtain much higher values. For example, Ferrazzoli et al [40] obtains values between ∼ 0.4 to 0.6 for the "branch-layer of an old forest at L-band (θ 0 = 35 • )", Xie et al [41] reports ω-values ranging from 0.3 to as high as 0.8 for "soy-and cotton fields with varying leave-and stem parameters at C-, X-and Ku-band" and Liao et al [42] investigates the dependence of ω on the vegetation-water content of corn-fields and finds values between 0.4 and 0.6 for V-polarized radiation at 1.26 GHz.…”