Radar Studies of Internal Stratigraphy and Bedrock Topography along the US ITASE Traverse

This project involves radar studies of internal layers and bedrock topography along the ITASE traverses. It uses a relatively low frequency radar which gives good penetration of the ice so that signals may be returned from up to 1 mile (2 km) in depth or more. In this way it is complementary to the other radar project on the traverse which focuses on the shallowest layers within the ice and therefore the most recent deposits from the atmosphere. Both views are important to understanding the history of ice flow in areas along the traverse and in interpreting change.

As the traverse proceeds, the radar will provide real-time information on ice thickness and internal layer structure to help in the selection of ice core drilling sites and to generalize spatially the observations made from the ice cores.

In addition to continuous coverage along the traverse route, the radar will be used in more detailed studies on grids surrounding each of the core locations to better characterize accumulation and bedrock topography in each area. This will also enable investigators to depict the ice flow patterns around each of the core sites, information which is helpful in interpreting climate.

The image above was created from a radar profile traversing Siple Dome, from ice stream C on the left, to ice stream D on the right. Radar signals are sent through the ice and are reflected back to a receiver. The glacial bed gives a strong echo that can easily be seen between 400 and 600 meters below sea level. Echoes also arise from buried debris layers which depict flow deformation of the ice; these layers are easily seen in this image in the upper half of the ice sheet.