Abstract
Abstract. Most glaciers in Patagonia have been rapidly shrinking during the past decades in response to ongoing global warming. To extend techniques to monitor their dynamics is crucial to understand individual glacier response to climate change and its consequences. In that context, our study aims to investigate recent dynamic behaviour of two near-site outlet glaciers placed at the Southern Patagonian Icefield (Tyndall and Grey glaciers) with the usage of simple and cheap remote sensing techniques. Sentinel-1 images were used to estimate surface velocity by using the Offset-tracking algorithm, while Sentinel-2 images were used to estimate area change in the ice front. Moreover, climatic variables (e.g., accumulated precipitation and air temperature) were analysed in order to assess its influence on glacier dynamics. Our results indicates that precipitation rather then temperature changes has been playing a major role in both glaciers retreat. While Tyndall tends to stabilize its retreat, Grey exponentially enhances retreat by its east tongue. Additionally, mean ice speed was of 0.448 ± 0.242 m.day−1 for Grey and 0.439 ± 0.245 m.day−1 for Tyndall, which agrees with literature. However, high ice speeds near the ice front indicated by previous work could not be captured here. Our results also suggests that ice flow is a delayed response of precipitation in the accumulation zone, and that may be the cause of decrease in Tyndall’s retreat. Overall, Offset-tracking is an useful tool for studying time series of Patagonian glaciers dynamics. It should be used carefully, however, around high dynamical regions such as the glacier terminus.
Highlights
Most Patagonian glaciers have been rapidly shrinking during the past decades due to recent global warming, which may have implications for sea-level rise (Aniya et al, 1997; Rignot et al, 2003)
Water ow through glaciers exerts an important control on ice dynamics, and in uences the quantity and quality of water delivered to environments downstream of glacierized basins (Brown, 2002)
Since total mass loss by melting at the calving front is found to be small compared to the mass loss by calving (Vieli et al, 2002), front variability may be a useful proxy for estimating frontal ablation
Summary
Most Patagonian glaciers have been rapidly shrinking during the past decades due to recent global warming, which may have implications for sea-level rise (Aniya et al, 1997; Rignot et al, 2003). Andes glaciers experienced the largest cumulative mass losses in the world since 1961 (Zemp et al, 2016); from which the Southern Patagonian glaciers presents the most negative mass balance as well as the strongest thinning rates over the entire Andes Cordillera (Dussaillant et al, 2019). Climate change affects both temperature and precipitation patterns, and influences the accumulation and ablation rates of glaciers (Strozzi et al, 2002). Since total mass loss by melting at the calving front is found to be small compared to the mass loss by calving (Vieli et al, 2002), front variability may be a useful proxy for estimating frontal ablation
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