Velocities field of mountain glacier obtained by synthetic aperture radar interferometry. comparison of insar and surveyed velocities

The Mer de Glace and Argentiegravere glaciers are located in the Mont Blanc region, French Alps. They are temperate glaciers and their velocity flow is about one hundred meters a year (~270 mm a day). This paper presents a use of synthetic-aperture radar (SAR) interferogram obtained from the two European Remote-Sensing satellites (ERS1-2) to measure the motion of Mer de Glace and Argentiegravere glaciers. We investigate whether the interferometric data are quantitatively consistent with terrestrial velocity measurements along two transverse profiles and two longitudinal profiles. Interferometric and terrestrial velocity are in agreement if a (terrestrially measured) surface-normal velocity component is properly accounted for. This suggest that both the interferometric velocities and the conversions of terrestrial data to the winter period are reliable. Finally we show that the application of repeat-pass SAR interferometry to the glaciers enable precise mapping of ice flow dynamics at a much higher level than usually obtained