Engineers with the University of Kansas have taken Synthetic Aperture Radar (SAR) images of the bedrock beneath ice sheets near Summit Camp, Greenland. The radar signal was broadcast in the range of 120–300 MHz, which is roughly equivalent to television stations in the U.S. broadcasting in channels 7 through 13. Using a new algorithm to compute the estimated direction of an arriving signal, they have been able to reproduce the topography of the bedrock with a relative accuracy of 10 meters. From the Kansas City infoZine article.
The radar system is a game-changing development for researchers in global climate change. Previously, glaciologists could only know the thickness of the ice and bed conditions along a single line from a sole pass of a radar or at a single point where ice core samples had been drilled.
From the paper Ice-sheet bed 3-D tomography in the Journal of Glaciology :
Three-dimensional tomographic techniques produce a 3-D image of the ice and bed. For digital elevation model generation, we are interested in locating the ice–bed interface in the 3-D space. This work presents a simple, automated method for finding the ice–bed surface and removing point errors. Automation is critical for surface fitting due to the large number of data collected.
via Kansas City infoZine : KU Radar System Provides 3D Image of Earth Through Miles of Ice
via Journal of Glaciology : Ice-sheet bed 3-D tomography
