Preprints
https://doi.org/10.5194/tc-2021-323
https://doi.org/10.5194/tc-2021-323

  01 Nov 2021

01 Nov 2021

Review status: this preprint is currently under review for the journal TC.

Modelling the effect of submarine iceberg melting on glacier-adjacent water properties

Benjamin Joseph Davison1,2, Tom Cowton1, Andrew Sole3, Finlo Cottier4,5, and Pete Nienow6 Benjamin Joseph Davison et al.
  • 1Department of Geography and Sustainable Development, University of St Andrews, St Andrews, UK
  • 2School of Earth and Environment, University of Leeds, Leeds, UK
  • 3Department of Geography, University of Sheffield, Sheffield, UK
  • 4Scottish Association for Marine Science, Scottish Marine Institute, Oban, UK
  • 5Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway
  • 6School of Geosciences, University of Edinburgh, Edinburgh, UK

Abstract. The rate of ocean-driven retreat of Greenland’s tidewater glaciers remains highly uncertain in predictions of future sea level rise, in part due to poorly constrained glacier-adjacent water properties. Icebergs and their meltwater contributions are likely important modifiers of fjord water properties, yet their effect is poorly understood. Here, we use a 3-D ocean circulation model, coupled to a submarine iceberg melt module, to investigate the effect of submarine iceberg melting on glacier-adjacent water properties in a range of idealised settings. Submarine iceberg melting can modify glacier-adjacent water properties in three principle ways: (1) substantial cooling and modest freshening in the upper ~50 m of the water column; (2) warming of Polar Water at intermediate depths due to iceberg melt-induced upwelling of warm Atlantic Water, and; (3) warming of the deeper Atlantic Water layer when vertical temperature gradients through this layer are steep (due to vertical mixing of warm water at depth), but cooling of the Atlantic Water layer when vertical temperature gradients are shallow. The overall effect of iceberg melt is to make glacier-adjacent water properties more uniform with depth. When icebergs extend to, or below, the depth of a sill at the fjord mouth, they can cause cooling throughout the entire water column. All of these effects are more pronounced in fjords with higher iceberg concentrations and deeper iceberg keel depths. These iceberg melt-induced changes to glacier-adjacent water properties will reduce rates of glacier submarine melting near the surface, but increase them in the Polar Water layer, and cause typically modest impacts in the Atlantic Water layer. These results characterise the important role of submarine iceberg melting in modifying ice sheet-ocean interaction, and highlight the need to improve representations of fjord processes in ice sheet-scale models.

Benjamin Joseph Davison et al.

Status: open (until 27 Dec 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Benjamin Joseph Davison et al.

Benjamin Joseph Davison et al.

Viewed

Total article views: 346 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
263 81 2 346 0 0
  • HTML: 263
  • PDF: 81
  • XML: 2
  • Total: 346
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 01 Nov 2021)
Cumulative views and downloads (calculated since 01 Nov 2021)

Viewed (geographical distribution)

Total article views: 320 (including HTML, PDF, and XML) Thereof 320 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 26 Nov 2021
Download
Short summary
The ocean is an important driver of Greenland glacier retreat. Icebergs influence ocean temperature in the vicinity of glaciers, which will affect glacier retreat rates, but the effect of icebergs on water temperature is poorly understood. In this study, we use a model to show that icebergs cause large changes to water properties next to Greenland's glaciers, which could influence ocean-driven glacier retreat around Greenland.