Ice-penetrating radar survey of the subsurface debris field at Camp Century, Greenland

Abstract The warming climate is changing the surface dynamics of the Greenland Ice Sheet, including the balance between snowfall and melt. Increasing surface melt impacts the structure of the relatively porous near-surface layer known as firn. Camp Century, a base abandoned in 1967, now comprises a subsurface debris field within the firn in Northwest Greenland. We collected 80 km of 100 or 250 MHz radar data in nested grids over this subsurface debris field. Here, we present a comprehensive analysis and interpretation of this ice-penetrating radar survey. The vast majority (95%) of subsurface reflectors are located at depths of greater than 32 m. The tunnel network, as well as an overlying layer associated with historical surface activities, is readily visible in the radar data. This subsurface debris field is approximately circular with a radius of less than 1 km. Local downwarping of clear internal layers – likely annual accumulation layers - identifies now-collapsed liquid sumps. Analysis of radar signal polarity suggests that liquid hydrocarbons are likely present in one of these sumps. The radar data and a geo-referenced site map of Camp Century are freely accessible at www.campcenturyclimate.dk .