Estimation of Glacier Dynamics for Glacier De Corbassière Using Satellite Image Cross Correlation Approach

The present work investigates the surface ice flow velocity and the spatially distributed ice thickness of the Corbassière glacier (Glacier de Corbassière), which is a mountain glacier situated in the Alpine region of Switzerland. An automatic python-based algorithm has been adopted to estimate the spatially distributed glacier ice thickness over the whole surface of the glacier which uses ice flow law and surface ice flow velocity. For assessing the ice flow velocity of the glacier, Landsat-8 optical data with a Panchromatic band of spatial resolution of 15 m have been used for the water year 2017–2018. This approach works on sub-pixel normalization using non-proprietary software COSI-Corr (Co-registration of Optically Sensed Images and Correlation) in the ENVI (Environment for Visualizing Images) platform. Results show a maximum flow velocity of 70 m/year with a mean flow velocity of 19 m/year during the period of study. The ice thickness derived from ice flow law using the estimated surface velocity and the slope was found to be around 250 m and 78 m on a maximum and average scale respectively. On analyzing the spatially distributed surface flow map of the glacier, patchy high flow velocity over the accumulation and mid ablation zones (elevation > 2750 m) has been seen due to the presence of crevasses. The lower ablation zone and snout show an average surface velocity of less than 15 m/year. The surface flow velocity results obtained from the present study were validated with the stack point measurements (in-situ) of the Glaciological Report No. 139/140, ‘The Swiss Glaciers 2017/18 and 2018/19’. A comparative study reveals that the results correlate well with five out of seven stack points with surface ice flow velocity error less than 7 m/year.