Glacier monitoring One of the key indicators of global change is variation in glacier activity. Glacier monitoring is therefore essential for the prediction of potential environmental threats due to environmental change. Climate Change and Environment © PhotoDisc OMEGA project has developed a monitoring system, giving cost effective, accurate information to scientists and the public. Glaciers are monitored using INSAR, or SAR INterferometry. SAR interferometry uses the same point on the ground to generate interference between the two-phase signals. Space-borne instruments ERS-1/2 and RADARSAT Synthetic Aperture Radar (SAR) emit electromagnetic radiation (EMR) and then record the strength and time delay of the returning signal to produce images of the ground. The analysis of spaceborne SAR and optical imagery has provided evidence of significant glacier retreat over the last five years throughout Europe. An image-based approach to rheological modelling was devised based on repetitive SAR interferograms and high resolution IKONOS imagery. The system has been tested and validated in different glacier environments. A new methodology for INSAR surveying and modelling has also been developed, using an algorithm based on the calculation of interferometric phase gradients, GINSAR. Glacier slope maps are generated and differences between multitemporal slope maps provide simple, fast solutions to modelling of the glacier surface, unsupervised glacier change and motion estimation. Results from test sites monitored with this new algorithm have been accurate and expedient. The technique can be used to monitor temporal changes in glacier accumulation rate and mass balance on a regional scale. The algorithm is available in a software package.
