L-Band Full-Wave Simulations of the Effective Permittivity of Bi/Tri-Continuous Media With Applications to Firn Aquifer in Polar Regions and Terrestrial Wet Snow

Full-wave simulations of the effective permittivity of firn aquifer and wet snow at L-band are reported. The Monte Carlo simulations are carried out for bicontinuous media embedded in a sphere, and the scattering cross section and absorption cross section are calculated. By averaging over realizations, the effective permittivity is extracted by comparing it with Mie solutions. The simulations are validated by using three numerical methods of 3-D solutions of Maxwell equations: finite difference frequency domain (FDFD), finite element method (FEM), and the discrete dipole approximation (DDA). Full-wave simulation results are compared with those from the classical Maxwell–Garnett and Polder–van Santen mixing formulas. The results show large differences from mixing formulas when there are large permittivity contrasts between the background medium and the scatterers, which are scenarios in aquifer and wet snow. The significance of these results is examined for the L-band microwave remote sensing of terrestrial wet snow and aquifer in polar regions.