Ice-sheet elevations from across-track processing of airborne interferometric radar altimetry

• Published in: Geophysical Research Letters
• Main Authors: Hawley, R. L., Sheperd, A., Cullen, R., Helm, Veit, Wingham, D. J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2009
• Subjects: Antarc*; Antarctica; Greenland; Ice Sheet
• Online Access: https://epic.awi.de/id/eprint/21155/; https://doi.org/10.1029/2009GL040416; https://hdl.handle.net/10013/epic.33644

Interferometric Radar Altimeters (IRA's) use dual receive antennas to overcome one of the spatial limitations of pulse-limited altimeters. In a conventional IRA measurement, the range and across-track direction of a scatterer are determined using the phase difference between the antennas. We demonstrate a method of determining multiple elevation points across a swath orthogonal to the instrument ground track in regions of steep terrain, such as ice-sheet margins. We use data from an airborne IRA (a prototype of the CryoSat-2 instrument), and compare the results to simultaneous Airborne Laser Scanner (ALS) observations. This application results in a 75-fold increase in measurement density compared to conventional radar altimetry. Along a ∼2.5 km ground track, the RMS departure between the IRA- and ALS-derived measurements was 1.67 m. Based on our result, although our approach is limited to areas of relatively steep slope, a 25- to 75-fold increase in elevation measurements could be achieved in coastal regions of Antarctica and Greenland with similar processing of CryoSat-2 data.