THE APPLICATION OF GROUND-PENETRATING RADAR TO THE STUDY OF GLACIAL HYDROLOGY

A major problem in the study of glacial hydrology has always been determining the exact location and interconnections of englacial and subglacial drainage networks. Advances in ground-penetrating radar (GPR) technology makes this possible. A PulseEKKO IV GPR system was used to survey the accumulation area and the termini of two high arctic glaciers, and a proglacial icing. Near-surface detail was best imaged using a 200 MHz/400 V configuration, while the 50 MHz/1000V configuration imaged through thicker ice. While minor variations in ice properties were not imaged, major changes in ice character were detected and large air, water, and sediment inclusions were mapped with gridded surveys. Pulse phase modeling was used to differentiate air-filled from water-filled voids. The low attenuation and decreased directivity of the radar signal in ice resulted in the generation of very long diffraction tails (>30 m) from point source reflectors within the ice. This enabled the determination of the precise location of these reflectors by interpolating their position between survey lines. As a result, the three dimensional position of drainage tunnels within the ice was mapped. Key words: ground penetrating radar, glaciology, hydrolog