The reflection properties of radio waves on the ice cap

Abstract

The surface of the Greenland and Antarctic continent is covered by a thick ice cap. When the radio waves are reflected from this surface, a large percentage of energy is attenuated due to the dielectric properties of the ice and snow. The average thickness of the ice cap is known to be about 2700 meters by seismic sounding measurements. The surface is composed of snow and becomes harder in proportion to the depth until it becomes ice under the pressure of its own mass. The ice contains tiny air cells under high pressure. The measured value of the dielectric constant of snow and ice is 1.5 to 4.0, and the dissipation factor \tan \delta is 0.1 to 0.0002 with the frequency range from 1 MHz to 1 GHz. The propagation loss is calculated to be 0.07 dB/m. The magnitude of the reflection coefficient of radio waves on the surface for vertical incidence is calculated to be about 0.1. From this investigation it is shown that the large attenuation of radio waves reflected by the ice cap becomes an important factor similar to the attenuation of the ionospheric reflection.