An Air-to-Soil Transition Model for Discrete Scattering-Emission Modelling at L-Band
The sketch of the air-to-soil transition (ATS) model (a) and the dielectric depth profile in the ATS zone (b). refers to the cumulative probability of density of , and 1- corresponds to the total air volume fraction of the ATS zone. is the total dielectric roughness thickness (unit: cm) of a soil area with the order by ( cm at L-band). (unit: cm) refers to the dielectric roughness thickness at the topsoil structures. (unit: cm) is the dielectric roughness thickness in the soil volume. is the average surface geometric height with standard deviation (unit: cm). The ECH2O 5TM probes (Decagon Devices, Inc., USA) are located at different depths (e.g., 2.5 and 10 cm). (b) describes the under wet and dry soil conditions with of 0.9 cm, in which is the real part of the dielectric constant of bulk soil, for , and for .