Preprints
https://doi.org/10.5194/os-2022-16
https://doi.org/10.5194/os-2022-16
 
01 Apr 2022
01 Apr 2022
Status: this preprint is currently under review for the journal OS.

The role of oceanic heat flux in reducing thermodynamic ice growth in Nares Strait and promoting earlier collapse of the ice bridge

Sergei Kirillov1, Igor Dmitrenko1, David G. Babb1, Jens K. Ehn1, Nikolay Koldunov2, Søren Rysgaard1,3,4, David Jensen1, and David G. Barber1 Sergei Kirillov et al.
  • 1Centre for Earth Observation Science, University of Manitoba, Winnipeg, Manitoba, Canada
  • 2Alfred Wegener Institute, Bremerhaven, Germany
  • 3Arctic Research Centre, Aarhus University, Aarhus, Denmark
  • 4Greenland Institute of Natural Resources, Nuuk, Greenland

Abstract. The ice bridge in Nares Strait is a well-known phenomenon that affects the liquid and solid freshwater flux from the Arctic Ocean through the strait and controlling the downstream North Water polynya in the northern Baffin Bay. Recently, the ice bridge has been in a state of decline, either breaking up earlier or not forming at all, and thereby increasing the sea ice export out of the Arctic Ocean. The decline of the ice bridge has been ascribed to thinner and therefore weaker ice from the Arctic Ocean entering Nares Strait, however local forcing also affects the state of the ice bridge and thereby influences when it breaks up. Using a variety of remotely sensed data we examine the spatial patterns of sea ice thickness within the ice bridge; highlighting the presence of negative ice thickness anomalies on both the eastern and western sides of the Strait, and identifying a recurrent sensible heat polynya that forms within the ice bridge near Cape Jackson in northwestern Greenland. Using the sea ice-ocean model FESOM2, we then attribute these ice thickness anomalies to upwelling of warm modified water of Atlantic origin (mAW) that reduces thermodynamic ice growth throughout winter. The consequently weaker and thinner areas within the ice bridge promote instability and the earlier break up. This work provides new insight into the Nares Strait ice bridge, and highlights that a combination of thinner ice and warmer mAW entering the Strait is contributing to its decline.

Sergei Kirillov et al.

Status: open (until 27 May 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on os-2022-16', Anonymous Referee #1, 10 May 2022 reply
  • RC2: 'Comment on os-2022-16', Humfrey Melling, 16 May 2022 reply

Sergei Kirillov et al.

Data sets

1km-res FESOM2 data for Nares Strait Sergei Kirillov, Nikolay Koldunov https://doi.org/10.5281/zenodo.6360063

Sergei Kirillov et al.

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Latest update: 27 May 2022
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Short summary
The sea ice bridge usually forms during winter in Nares Strait and prevents ice to drift south. However, this bridge has recently become unstable, and in this study we investigate the role of oceanic heat flux in this decline. Using satellite data, we identify areas where sea ice is relatively thin and further attribute those areas to the heat fluxes from the warm subsurface water masses. We also discuss the potential role of such impact on the ice bridge instability and the earlier break up.