Three arrays of Radio-Echo Sounding profiles have been recorded on the Worthington Glacier. The 1994 survey was recorded using different field methods than the field methods used in 1996 & 1998. The same eqpuipmet was used in all three surveys as well as the same data processing techniques.
The first profiles were recorded in 1994 and oriented parallel to the ice flow direction. The locations of these profiles were not measured accurately, and the profiles were recorded a few at a time over a period of about a month. The resulting glacier bed map was not very accurate, with a resolution of about 40 x 40 meters.
The 1996 radar profiles were recorded in the cross-glacier direction. The location of every fourth trace of each profile was measured with optical surveying equipment using a local coordinate system seen in the map below. The profiles were spaced 20 m apart and a trace recorded every 5 m along each profile. The resulting glacier bed map had a resolution of 20 x 20 meters.
In 1998 we used the radio-echo sounding equipment to look for englacial conduits that transport surface meltwater through the glacier to its bed. This study required the maximum resolution that we could obtain from the eqpuipment, so the profiles and traces were spaced every 5 m. Every fourth trace on each profile was surveyed to locate it to within 0.25 m and the entire RES survey was recorded in two days. The survey was repeated a month later to look for changes in the geometry of any englacial conduits found. The first RES survey was processed to produce a map of the glacier bed surface with a resolution of 17.5 x 17.5 m. The maximum resolution obtainable by an RES survey is half of the signal wavelength. Our 5 MHz system, therefore, can obtain 17 x 17 m resolution under the best of circumstances.
Return to the Worthington Glacier Map
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Updated: July 01, 2002
© 1998, Brian C. Welch,
Univ. of Wyoming