Passive microwave sensing of soil moisture under vegetation canopies

Abstract

Vegetation cover has a significant effect on the ability of passive microwave radiometers to detect changes in near‐surface soil moisture. A quantitative technique for isolating the effect of vegetation was developed using a theoretical model as the basis of a parametric approach. This approach was evaluated using data collected by truck‐mounted sensors over experimental plots. Results show that a microwave radiometer operating at a 21‐cm wavelength can provide volumetric surface soil moisture estimates to ∼5% of accuracy for fields covered with moderate vegetation. In addition, all of the data required for applying the parametric model can be measured using remote sensing.