Glacier elevation changes in the Semi-Arid Chilean Andes from Synthetic Aperture Radar

Globally, mountain glaciers are retreating under the effects of climate change. Many of these mountain glaciers are part of important water tower regions (Immerzeel et al., 2020), and their retreat threatens the water security of local communities and downstream catchments. In the Semi-Arid Chilean Andes, mountain glaciers are particularly important as water from precipitation is limited in this arid climate, which is currently experiencing a ‘mega drought’.   However, estimating the changing ice volume is challenging due to two key reasons. Firstly, a large proportion of the glaciers are small in extent and have a high degree of debris-cover, meaning the ice extent is challenging to measure using satellite remote sensing data. This is most pronounced in the case of rock glaciers, which are numerous in this region. Secondly, there are few in situ observations of ice thickness and extent to validate the multispectral remote sensing observations. Given this context, we present new observations of glacier elevation changes using derived from recently acquired Synthetic Aperture Radar (SAR) observations. This work aims to better understand how glacier mass balance in the Semi-Arid Chilean Andes affects water resources for downstream catchments, and we evaluate the applicability of the SAR data including ESA’s Sentinel-1 in this context. We use DEM differencing and radar backscatter analyses to study glacier changes in order to track retreat and estimate changing ice content. We will present the findings of this work and comment on the possible opportunities and limitations this approach offers.