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Shifts of the Recirculation Pathways in central Fram Strait drive Atlantic Intermediate Water Variability on Northeast Greenland shelf
  • Rebecca A. McPherson,
  • Claudia Wekerle,
  • Torsten Kanzow
Rebecca A. McPherson
Alfred Wegener Insitute

Corresponding Author:[email protected]

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Claudia Wekerle
Alfred Wegener Institute for Polar and Marine Research
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Torsten Kanzow
Alfred Wegener Institute in Bremerhaven
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Abstract

Increased oceanic heat transport plays a key role in the accelerated mass loss of Greenland’s marine-terminating glaciers. The melt rate of major glaciers in Northeast Greenland (NEG) is controlled by ocean variability, in particular warm Atlantic Intermediate Water (AIW), on the continental shelf. A high-resolution configuration of the ocean sea-ice model FESOM2.1 is validated at local and regional scales, and used to investigate the drivers of AIW temperature variability on the NEG shelf. The seasonal to decadal variability of the AIW is characterised, featuring both pronounced interannual fluctuations and a long-term warming trend. A major source of AIW is Atlantic Water (AW) originating from the West Spitsbergen Current that recirculates in Fram Strait. AW anomalies are advected westwards and partly control the AIW temperatures on the shelf. Increased AIW temperatures are also connected to more pronounced northern and middle branches of recirculating AW in Fram Strait, and enhanced AW temperatures more regionally. This strengthening of the pathways brings more and warmer AIW onto the northern part of the NEG shelf. There, it circulates anti-cyclonically and results in shelf-wide warming. Regional atmospheric forcing is connected to the changes in the AW circulation regime. The strengthening of the northern AW branches is likely caused by anticyclonic wind anomalies over the Barents Sea that drive an enhanced northwards AW transport in Fram Strait. Thus, controlled by a combination of both upstream and regionally forced circulation conditions, the changes in local AIW temperatures may also affect the oceanic heat transport reaching the Arctic Ocean.
11 Apr 2023Submitted to ESS Open Archive
16 Apr 2023Published in ESS Open Archive