Mapping Supraglacial Water as a Window into Surge Hydrology: Linking Surface Water, Drainage Efficiency, and Surge Dynamics on Negribreen, Svalbard

Abstract

We analyze the dynamics of Negribreen Glacier System, a polythermal glacier in Svalbard, during its ongoing surge and investigate the role of supraglacial (surface) water as both an indicator of ice-dynamic processes and a driver of surge evolution. We identify three distinct surge phases: the initial acceleration phase, mature phase, and return to quiescence. Comparing the quiescent supraglacial hydrological state to each of the surge phases, we observe a sudden increase in hydrological connectivity between the glacier surface and base during initial acceleration, followed by a gradual return to quiescent water extent. In the mature surge phase, emergent water-filled crevasses coincide with regions of compressive forcing and extensive deformation, follow local accelerations, and preceded smaller, secondary accelerations. Additionaly, rapid drainage of surface ponds is observed in the mature surge. A data-fusion approach, using Maxar WorldView(c) imagery, ICESat-2 altimetry, and Sentinel-1 Synthetic Aperture Radar, is taken to create a time series of supraglacial water maps, water volumes, surface velocity changes, and spatial ice surface roughness. These observations provide a qualitative (process understanding) and quantitative (water time series) basis for supraglacial water sources as a driver and indicator of surge activity for Arctic glaciers.