| Summary: | The aim of this research, carried out at Spitsbergen (Svalbard) over a 13-years period (2009-2022), is to monitor changes in the transfer from the continent to Kongsfjorden of sedimentary and liquid flows associated to continental glaciers of the southern coast of the fjord. The idea is to identify periods, threshold values, when the system switches from glacial to periglacial and to identify the associated processes. As a result of climate change, the deltas and prodeltas, fed by sub-glacial rivers draining material from basal moraines formed by continental glaciers (Le Vestre and Midtre-Lovenbreen), could prograde, stagnate or even be eroded. We used Edgetech 272 TD side-scan sonar and acquired acoustic mosaics, calibrated with sediment samples, to track the evolution of the prodeltas. We identified 3 phases of evolution during our observation time: progradation, erosion and finally stabilization of the prodeltas. At the same time, onshore acquisition of the coastline (i.e with a DGPS, enabled us to monitor the evolution of the deltas. By using these in situ data to calibrate the automated shoreline detection algorithm, it should be possible to extract the waterline over the last 25 years, using Landsat and Sentinel-2 satellite images (1995, 2006, 2018, 2019, 2020, 2021. Finally, to estimate the transfer of flows between the glacier and the fjord and to assess to the isostatic rebound of the continent, we analysed satellite positioning GNSS and space gravimetry (GRACE and GRACE -Follow one) data the Erath’s response to mass transfer with millimetric accuracy. These complementary approaches enable us to understand the “glacier to fjord” transfer system as a whole and to follow the isostatic rebound impact on the coastal evolution.
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