Measurement of the Thickness of the Greenland Ice Sheet and High-Resolution Mapping of Internal Layers
Project Award Date: 08-15-1999
As part of a long-term study, researchers from the Radar Systems and Remote Sensing Laboratory (RSL) travel north to Greenland almost every year to measure the ice sheet thickness. RSL's research in Greenland began in 1993 and is part of a large NASA project involving scientists from NASA centers, other universities, and institutes in Denmark and the United Kingdom. The objective of the project is to determine the mass balance of the Greenland ice sheet with an ultimate goal of directly linking ice sheet variations to changes in global sea level.
Sea level has been rising about 2 mm/year during the last century. The factors contributing to this increase are the thermal expansion of the ocean, melting of mountain glaciers, and changes to the great ice sheets in Antarctica and Greenland. However, there is a large uncertainty in the relative contribution of each component. Since the great ice sheets lock up about 80 percent of the world's fresh water, their potential contribution to sea level can be large. If the Greenland ice sheet were to melt completely, it would cause sea level to rise about 7 m with devastating consequences to coastal regions.
Sivaprasad Gogineni, Deane E. Ackers Distinguished Professor of Electrical Engineering and Computer Science, and David Braaten, KU associate professor of physics and astronomy, are working on the most recent aspect of this ongoing project. Gogineni has co-authored a study that appeared July 21, 2000, in the journal Science. The KU team acquired ice thickness data for this study, which concluded that interior regions of the ice sheet are not changing, whereas ice sheet margins in the southeast are showing dramatic decreases in ice volume. Gogineni and Braaten said that long-term observations coupled with glaciological and atmospheric models are required to explain and understand the significance of these observed changes. Ice thickness is a key variable in understanding and modeling glacier dynamics.
In 1995, KU undergraduate students developed for a senior design project the prototype of RSL's radar for measuring ice thickness using Radio Frequency Integrated Circuits (RFICs). This radar-Coherent Radar Depth Sounder, or CoRDS-has been flown on a NASA P-3 aircraft, providing precise ice thickness data over vast areas of the Greenland ice sheet.
Jon Bamber at the University of Bristol, United Kingdom, has combined new ice thickness data from KU with previous data sets to generate a more complete thickness and bed topography map of the entire ice sheet. These maps are now being used in modeling studies of the dynamics of the ice sheet and its response to climate change.
The KU team continues to be involved in future ice sheet measurements and is now developing a new high-resolution, aircraft-based ice penetrating radar for obtaining unique snow accumulation measurements over the ice sheet.
Faculty Investigator(s): Sivaprasad Gogineni (PI), David Braaten, James Stiles
Student Investigator(s): Saikiran Namburi, Vijaya Ramasami, Krishna Kumar Gurumoorthy, Sreenivas Penumarthy, James Pingenot, Kuok-Wai (Wilson) Wong, Bharath Parthasarathy, Jason Henslee
Primary Sponsor(s): National Aeronautics and Space Administration (NASA)