Integrated Modeling of Active and Passive Microwaves and Passive Optical Signatures

A method of physical integration of electromagnetic (EM) interaction models is presented here to estimate the backscattering coefficient (BSC) for L-band, brightness temperature (TB) for L- and C-Band and the reflectance for visible (VIS) and near-infrared (NIR) region for dynamic vegetated terrain. The SPIN (Spectrum Invariant Interaction) model is obtained by solving vector radiative transfer (VRT) equations kernel-based and therefore for different wave interaction mechanisms. To demonstrate its application for the microwave region, the measurements during the growing cycle of corn from the Eleventh Microwave, Water, and Energy Balance Experiment (MicroWEX-11) have been used. For the optical part the results are compared with the PROSAIL model. By applying the SPIN model in the radar regime, it could be shown that the modeled backscattering coefficients (BSC) correlate strongly with the vertical polarization measurements (Pearson 0.83, R
²
0.69) and are less correlated with the horizontal measurements (Pearson 0.45, R
²
0.20). In addition, the modeled brightness temperatures (L- and C-band) in both polarization states are also correlated with the MicroWEX-11 measurements (L-band: Pearson 0.755, R
²
0.57; C-band: Pearson 0.73, R
²
0.53). Finally, the optical results are consistent with the results of other standard optical models (Pearson 0.99, R
²
0.98), like PROSAIL.