Measurement and behavior of dual-polarization vegetation optical depth and single scattering albedo at 1.4- and 5-GHz microwave frequencies

A measurement procedure has been developed and tested to determine horizontal and vertical polarization radiative transfer properties, i,e., single scattering albedo (ω) and optical depth (τ), of vegetation under field conditions. The procedure was applied to a wheat crop for a series of biomass densities. The measurements were done using two different radiometers (1.4 and 5 GHz) and for different view angles. The measurements and calculations indicated that the ratios of horizontal and vertical polarization radiative transfer properties (α=Γ_h/Γ_ν, α'=τ_h/τ_ν and β=ωh/ω_ν) are slightly dependent on view angle. However, no significant dependence on biomass density could be discerned