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Back to Young UTIG Researchers Talks
Anomalous Radar Reflectors and Topographic Interference
Below South Pole Subglacial Lake
By Benjamin Williams
Abstract:
Airborne ice sounding radar data collected during the 2001 season near the South Pole indicates a strong radar return following either a clean-glacial-ice/dirty-ice interface or an ice/rock interface. It is plausible, but unlikely, that radar could penetrate and return a strong echo from beneath a clean-ice/dirty-ice interface, but it is very unlikely that radar will return a signal through rock. However, it is possible that the radar echo actually returns from terrain to the side of the radar on the airborne platform. Evaluation of the region shows that subglacial bedrock located in the first side lobe of the radar antenna pattern is the proper depth beneath the ice surface to explain the echoes in question, after accounting for oblique two-layer propagation. This terrain is also of a shape conducive to strong radar reflections. To determine if the returns are the result of this side lobe interference, and are not an indication of an error in data, I shall use the latitude and longitude of the radar position during the measurements to compare the difference in position of the strong geometric reflector and the apparent radar return. Preliminary evaluation indicates that topography within the first radar antenna side lobe resulted in the anomalous echo return, and the lake in the vicinity of the South Pole is apparently not penetrable by this radar.
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