Estimation of surface flow speed and ice surface temperature from optical satellite imagery at Viedma glacier, Argentina

The Viedma glacier is the largest glacier in Argentina and one of the most dynamic in the Southern Patagonian Icefield. It is a strategic water source. This study analyzes the interactions of glaciological variables that help better explain the behavior of the Viedma glacier. This paper presents the study of surface flow speed and ice surface temperatures during the 2015-2016 warm season by using remote sensing data and includes the statistical correlation between those variables. In addition, a reconstruction of the front fluctuation between 1979 and 2016 through CORONA and LANDSAT images is included. Finally, the displacement modes dominating the Viedma glacier are suggested. Our results showed that the mean surface flow speed during the study period was of around 1.2 ± 0.3 md−1 and reached maximum values of 5.5 ± 0.3 md−1 and 3 ± 0.3 md−1 at middle basin and terminus respectively. Thermal data revealed minimum values of −2 °C in the uppermost section of the study area, whilst the glacier's terminus showed supraglacial melt (values above pressure melting point). Front fluctuation analysis revealed the largest front retraction of the last 40 years between 2010 and 2016: around 281 my−1. Statistical correlation analysis and glaciological data suggested that the middle and lower basins of the Viedma glacier are widely dominated by basal sliding.