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There two profiles
are from an area with a particularly smooth bed near South Pole. The
UT/TUD image (left) was collected in 1998/99 as part of our Transantarctic
Mountains project. We repeated a section of the line in 2001 with the
UT/JPL system. Maybe its hard to see in these figures, but the layer
resolution is finer in the UT/JPL data that the UT/TUD data, though
the layers really aren’t resolved any deeper. |
Laura Lindzey, then an undergraduate research assistant at UT, spent a summer on characterizing the 'lake' surface from the echo amplitudes. She presented her results in a poster at Fall AGU, 2003. Here's the abstract: Airborne
Radar Sounding Studies of a Subglacial "Lake" Near South Pole
Station, Antarctica Radar ice sounding transects have revealed what appears to be a subglacial lake beneath 2800 meters of ice 10.5 kilometers from the South Pole. It has been proposed that sterile drilling be tested at this lake, a location accessible from the existing South Pole Station. Not only would this allow for techniques to be tested before risking contamination of Lake Vostok, but there is also the possibility of finding exotic microorganisms in a permafrost-like bed. Other workers have concluded that the lake is frozen by analyzing temperature measurements in the South Pole ice and extrapolating a base temperature at the "lake" using several different models. Here, we attempt to determine the material of the lake by extracting its properties through a complete solution to the radar equation. The radar equation accounts for all the factors that influence the returned echo strength, including radar system parameters and propagation effects. The largest unknown quantity is the ice loss, which depends on the temperature and impurities throughout the ice. For this analysis, we use temperature profiles corresponding to both a frozen and a liquid base and several possible dielectric loss models to compute ice loss. The strength of the returned echo is also affected by the material making up the "lake" and its roughness. The reflection coefficients calculated for a temperature profile allowing melt are not consistent with a glacier/liquid-water interface, thus implying that this "lake" is indeed frozen. Further analysis of the reflection coefficients indicates that they correspond to impure ice, and local topography suggests that this feature is possibly an ancient lake. ...and here's a poster snippet:
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