Extreme melting at Greenland's largest floating ice tongue ...

• Main Authors: Zeising, Ole, Neckel, Niklas, Dörr, Nils, Helm, Veit, Steinhage, Daniel, Timmermann, Ralph, Humbert, Angelika
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2024
• Subjects: glacier; Greenland
• Online Access: https://dx.doi.org/10.5445/ir/1000169567; https://publikationen.bibliothek.kit.edu/1000169567

The 79° North Glacier (Nioghalvfjerdsbrae, 79NG) is one of three remaining glaciers with a floating tongue in Greenland. Although the glacier has been considered exceptionally stable in the past, earlier studies have shown that the ice tongue has thinned in recent decades. By conducting high-resolution ground-based and airborne radar measurements in conjunction with satellite remote-sensing observations, we find significant changes in the geometry of 79NG. In the vicinity of the grounding line, a 500 m high subglacial channel has grown since ∼ 2010 and has caused surface lowering of up to 7.6 m a−1. Our results show extreme basal melt rates exceeding 150 m a−1 over a period of 17 d within a distance of 5 km from the grounding line, where the ice has thinned by 32 % since 1998. We find a heterogeneous distribution of melt rates, likely due to variability in water column thickness and channelization of the ice base. Time series of melt rates show a decrease in basal melting since 2018, indicating an inflow of ...