Electrical anisotropy in sea ice and a dual-polarization radar system to mitigate the effects of preferential attenuation in imaging sea ice

Preferential alignment in the physical structure of the sea ice crystal matrix results in anisotropy in the electrical properties of the bulk sea ice. Previous field data and our data demonstrate that both sea ice conductivity and its electrical anisotropy can impede ice thickness profiling using ground penetrating radar (GPR). Preferential attenuation caused by conductive anisotropy can reduce or eliminate ice bottom reflections when the polarization is not optimally aligned. A dual-polarization GPR configuration reliably imaged the sea ice/water interface, even in the presence of well-developed conductivity anisotropy. Additionally, by combining data from both polarizations, the system provides information about the horizontal direction of the ice matrix alignment, which may indicate the direction of dominant current flow underlying sea water. (C) 2015 Elsevier B.V. All rights reserved.