Backscattering simulation for nonuniform forest canopies using multilayer MIMICS

In this paper, we introduce a multilayer MIMICS for nonuniform forest canopies and present the model applications. The Michigan Microwave Canopy Scattering model (MIMICS) has been developed to simulate microwave backscattering from tree canopies. However, the crown-trunk canopy model is too restrictive for nonuniform canopy coverage. Multilayer MIMICS is developed to remove the two-layer canopy restriction. The model is a simulation solution to an array of radiative transfer equations and it includes the layer interactions between overlapping layers. This paper is focused on the model validation and application of multilayer MIMICS. Our collaborators have supplied us with extensive ground truth data from a 220,000 ha woodland and forest study areas within central Queensland, Australia. The field measurement is at the individual tree level. We can simulate the polarimetric backscattering for the ground measurement. AIRSAR data of the same area are obtained to validate the model simulation. The results show good agreement between the model simulation and SAR measurements. Analyzing an individual layer´s contribution offers better understanding of canopy composition effects on backscattering. The multilayer canopy configuration improves the estimate accuracy over that from a crown-trunk layer model, as in the older version of MIMICS.