Simultaneous retrievals of soil moisture and vegetation biomass from multi-configuration passive microwave measurements

A modeling approach is implemented to retrieve simultaneously soil and vegetation parameters from low-frequency microwave observations. The microwave observations were performed over a wheat field at L- and C-band. The model algorithm is based on a simple radiative transfer approach. The optical thickness τ is assumed to be proportional to the vegetation water content VWC. Two model parameters are used: r_τ and C_pol. The parameter r_τ is the ratio of the optical thickness at L- and C-band. The parameter C _pol is used to parameterize τ as a function of view angle and polarization. Using the inversion algorithm based on microwave and thermal infrared measurements, both soil moisture and VWC are retrieved during the vegetation cycle and during a four-hour irrigation phase. The study shows the inversion algorithm can provide accurate estimates of both soil moisture and vegetation biomass. The analysis also clearly demonstrates the high potential of the low-frequency passive microwave observations to monitor soil and vegetation characteristics