Characteristics of meltwater export from Jakobshavn Isbræ and Ilulissat Icefjord

• Published in: Annals of Glaciology
• Main Authors: Nicholas Beaird, Fiammetta Straneo, William Jenkins
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2017
• Subjects: glacier discharge; icebergs; ice/ocean interactions; meltwater chemistry; polar and subpolar oceans; Meteorology. Climatology; QC851-999; Ilulissat; Jakobshavn Isbræ; Annals of Glaciology; Ice Sheet; Jakobshavn; Jakobshavn isbræ
• Online Access: https://doi.org/10.1017/aog.2017.19; https://doaj.org/article/236d3413e1724d7fb0cb67f3de2d7aca

Jakobshavn Isbræ, which terminates in Ilulissat Icefjord, has undergone rapid retreat and is currently the largest contributor to ice-sheet mass loss among Greenland's marine terminating glaciers. Accelerating mass loss is increasing fresh water discharge to the ocean, which can feed back on ice melt, impact marine ecosystems and potentially modify regional and larger scale ocean circulation. Here we present hydrographic observations, including inert geochemical tracers, that allow the first quantitative description of the glacially-modified waters exported from the Jakobshavn/Icefjord system. Observations within the fjord suggest a deep-reaching overturning cell driven by glacial buoyancy forcing. Modified waters containing submarine meltwater (up to 2.5 ± 0.12%), subglacial discharge (up to 6 ± 0.37%) and large portions of entrained ocean waters are seen to exit the fjord and flow north. The exported meltwaters form a buoyant coastal gravity current reaching to 100 m depth and extending 10 km offshore.