Electromagnetic Interactions with Vegetated Soils: An Integrative Modeling Approach

Many attempts have been made and are undertaken to model the electromagnetic (EM) interaction with vegetation-coveredsoils at different frequencies. The modelling concepts and architectures range from empirical correlations to simple andsophisticated physical models [1, 2]. However, a general understanding of the physical properties and interactions along frequencyand for a wider part of the EM spectrum is difficult if the different models are treating the single frequencies and acquisitioncharacteristics (e.g. active or passive recording) separately. Due to the increasing fleet of earth observation sensors operating inmultiple frequency bands, demand for a spectrum-overarching EM modelling is becoming increasingly important. An integrativemodeling approach offers the chance that the different insights into biophysical and biochemical processes can be consideredconsistently including the respective dielectric properties and structural characteristics. With this objective we developed a kernel-driven electromagnetic interaction model using vector radiative transfer (VRT), called SPIN (Spectrum Invariant Interaction)model, which represents an integrated model approach for active and passive microwaves and passive optical as well as thermalsignatures [3]. Preparatory research for this study was the development of the RadOptics Model [4]. The main advantage of a kernel-driven approach is its analytical invertibility and the representation of the VRT as sum of linear equations, which leads toan enlargement of the information by including multiple frequencies. In addition, the model does not require semi-empirical or statistical calibration (i.e. all model parameters have physical meaning and none just for model adjustment.).