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Extreme melting at Greenland's largest floating ice tongue

Zeising, Ole; Neckel, Niklas; Dörr, Nils ORCID iD icon 1; Helm, Veit; Steinhage, Daniel; Timmermann, Ralph; Humbert, Angelika
1 Institut für Photogrammetrie und Fernerkundung (IPF), Karlsruher Institut für Technologie (KIT)

Abstract:

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 colder water into the cavity below 79NG. We discuss the processes that have led to the changes in geometry and conclude that the inflow of warm ocean currents has led to the extensive thinning of 79NG's floating ice tongue near the grounding line over the last 2 decades. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000169567
Veröffentlicht am 25.03.2024
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Photogrammetrie und Fernerkundung (IPF)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 22.03.2024
Sprache Englisch
Identifikator ISSN: 1994-0424
KITopen-ID: 1000169567
Erschienen in The Cryosphere
Verlag Copernicus Publications
Band 18
Seiten 1333–1357
Nachgewiesen in Scopus
Dimensions
Web of Science
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