Summary
Microwave remote sensing has been a useful tool to monitor the conditions of sea ice and ice extent in the polar regions. The study of the scattering mechanisms involved between the microwave and the sea ice medium is of interest to the researchers for understanding the important physical parameters affecting the radar returns received by the remote sensing satellite. The analysis carried out, and the knowledge gained, shall assist in the interpretation of the satellite images of the polar regions. In this paper, a theoretical model of a two layer medium is constructed consisting of a sea ice layer with a snow layer on top of it, and an ocean half space beneath it. In consideration of the number and density of the scatterers (brine inclusions and air bubbles) in the sea ice medium for the frequency range studied, it is regarded as an electrically dense medium as there is more than one scatterer within a wavelength. Unlike the conventional approach where sparse medium with independent scatterers is considered, the modeling of the electrically dense medium requires the consideration of coherent effects of the scatterers to be incorporated in the computation. An iterative solution with up to second order terms of the radiative transfer equation, which describes the energy propagation in the medium, is produced. The measurement data of the physical parameters of the sea ice area in Ross Island collected from 2001-2005 are applied to the model and the analysis of the results for various conditions and matching with Radarsat data is carried out. The effect of the sea ice thickness and the scattering mechanisms between the layers involved are studied to give a better understanding of the range of radar returns collected from the sea ice areas. With the snow layer on top of the sea ice, the wicking effect of the brine up to the snow-sea ice interface is also analysed. A study of the changes of the backscattering returns across frequency is also carried out to provide better understanding of the suitable frequency range to be considered for the monitoring of sea ice in polar regions.