  Using a bistatic radar system on the ice surface, we have studied
radiofrequency reflections off internal layers in Antarctic ice at the South
Pole. In our measurement, the total propagation time of ~ns-duration,
vertically broadcast radio signals, as a function of polarization axis in the
horizontal plane, provides a direct probe of the geometry-dependence of the ice
permittivity to depths of 1--2 km. Previous studies in East Antarctica have
interpreted the measured azimuthal dependence of reflected signals as evidence
for birefringent-induced interference effects, which are proposed to result
from preferred alignment of the crystal orientation fabric (COF) axis. To the
extent that COF alignment results from the bulk flow of ice across the
Antarctic continent, we would expect a measurable birefringent asymmetry at
South Pole, as well. Although we also observe clear dependence of reflected
amplitude on polarization angle in our measurements, we do not observe direct
evidence for birefringent-induced time-delay effects at the level of 0.1 parts
per mille.
