Seasonal flow variability of a temperate glacier in the Mont Blanc massif observed by GPS

International audienceWe present four years of GPS data acquired continuously on the Argentière glacier in the Mont Blanc massif, France. Our local permanent GPS network is composed of two stations on the glacier at altitudes of 2441 m and 2770 m, and two stations in static places, one in the valley of Chamonix at an altitude of 1121 m and the other on a rock outcrop near the glacier at the altitude of 2835 m. The measurements yield average displacement rates of about 13 cm/day for the upper glacier station (2770 m) and 17 cm/day for the lower site (2441 m). Moreover, we observe an annual variability of the displacement rates of up to 28 %, with fastest flow in late summer. The continuous monitoring of the Argentière glacier flow over several annual cycles can now be used to determine the correlation with climatological parameters such as temperature and cumulated precipitations