Using Satellite InSAR To Measure The Response Of Ice Caps To Climate Change
- Paper number
IAC-07-B1.I.15
- Author
Mr. Steven Palmer, United Kingdom
- Year
2007
- Abstract
Global climate changed during the 20th century, with the ten hottest years on record having occurred since 1991. Over the past 100 years, temperatures have risen by about 0.6 oC and sea level has risen by about 18cm, mostly due to thermal expansion of the oceans and melting land ice. 70% of the cryospheric contribution to 20th century sea level rise comes from glaciers and ice caps and they have the potential to add a further 50cm to the oceans. Earth’s ice caps are sensitive to changes in temperature and precipitation and, being widely distributed, can be used as indicators of regional and global climate change.
Measuring the mass balance of ice caps gives an indication of their response to climate change. In recent years, space-borne SAR (Synthetic Aperture Radar) instruments have provided accurate measurements of ice displacement which can be used to estimate glacier mass balance via the mass budget method. I use interferometry software to process pairs of raw ERS (European Remote sensing Satellite) SAR data scenes, using a digital elevation model to remove the topographic phase component. Application of a phase unwrapping algorithm yields ice displacement in the look direction of the radar. By combining data from ascending and descending satellite passes and assuming surface parallel ice flow, it is possible to derive ice velocity. Balance velocities can be computed from surface energy balance models and compared to the observed velocities to indicate how far the ice caps are from mass balance. I will present InSAR (Interferometric Synthetic Aperture Radar) derived ice velocity measurements and mass balance estimates for various sites including Langjökull, Iceland and King George Island, Antarctica.
- Abstract document