Shallow Fracture Buffers High Elevation Runoff in Northwest Greenland
Riley Culberg, Winnie Chu, Dustin M. Schroeder
Abstract
Abstract The expansion of refrozen ice slabs in Greenland's firn may enhance meltwater runoff and increase surface mass loss. However, the impermeability of ice slabs and the pathways for meltwater export from these regions remain poorly characterized. Here, we present ice‐penetrating radar observations of extensive meltwater infiltration and refreezing beneath ice slabs in Northwest Greenland. We show that these buried ice complexes form where supraglacial streams or lakes drain through surface crevasses into relict firn beneath the ice slabs. This suggests that the firn can continue to buffer mass loss from surface meltwater runoff and limit meltwater delivery to the ice sheet bed even after ice slabs have formed. Therefore, a significant time lag may exist between the initial formation of ice slabs and the onset of complete surface runoff and seasonal meltwater drainage to the subglacial system in interior regions of the ice sheet.