Evidence of Cascading Subglacial Water Flow at Jutulstraumen Glacier (Antarctica) Derived From Sentinel-1 and ICESat-2 Measurements

Abstract

Migration of subglacial water underneath thick Antarctic ice is difficult to observe directly but is known to influence ice flow dynamics. Here, we analyze a 6-year time series of displacement maps from differential Sentinel-1 SAR interferometry (DInSAR) in the upstream region of Jutulstraumen Glacier. Our results reveal short-term (between 12 days and 1 year) interconnected subsidence- and uplift events of the ice surface, which we interpret as a pressure response to the drainage and filling of subglacial lakes. This indicates an episodic cascade-like water transport with longer quiescent phases in a dynamically stable glacial setting. Abrupt events appear in the DInSAR time series and are confirmed by ICESat-2 altimetry. The events can be traced for a 1-year period along a (Formula presented.) 175 km flow path. We are able to observe the migration of subglacial water with unprecedented spatial and temporal resolution, providing a new observational baseline to further develop subglacial hydrological models.