Preprints
https://doi.org/10.5194/tc-2022-211
https://doi.org/10.5194/tc-2022-211
 
01 Nov 2022
01 Nov 2022
Status: this preprint is currently under review for the journal TC.

Modelling the evolution of Arctic multiyear sea ice over 2000–2018

Heather Christine Regan1, Pierre Rampal2, Einar Ólason1, Guillaume Boutin1, and Anton Korosov1 Heather Christine Regan et al.
  • 1Nansen Environmental and Remote Sensing Center, and the Bjerknes Center for Climate Research, Bergen, Norway
  • 2CNRS, Institut de Géophysique de l’Environnement, Grenoble, France

Abstract. Multiyear sea ice (MYI) cover in the Arctic has been monitored for decades using increasingly sophisticated remote sensing techniques, and these have documented a significant decline in MYI over time. However, such techniques are unable to differentiate between the processes affecting the evolution of the MYI. Further, estimating the thickness, and thus the volume of MYI remains challenging. In this study we employ a sea ice-ocean model to investigate the changes to MYI over the period 2000–2018. We exploit the Lagrangian framework of the sea ice model to introduce a new method of tracking MYI area and volume, which is based on identifying MYI during freeze onset each autumn. The model is found to successfully reproduce the spatial distribution and evolution of observed MYI extent. We discuss the balance of the processes (melt, ridging, export, and replenishment) linked to the general decline in MYI cover. The model suggests that rather than one process dominating the losses, there is an episodic imbalance between the different sources and sinks of MYI. We identify those key to the significant observed declines of 2007 and 2012; while melt and replenishment are important in 2012, sea ice dynamics play a significant role in 2007. Notably, the model suggests that convergence of the ice, through ridging, can result in large reductions of MYI area without a corresponding loss of MYI volume. This highlights the benefit of using models alongside satellite observations to aid interpretation of the observed MYI evolution in the Arctic.

Heather Christine Regan et al.

Status: open (until 27 Dec 2022)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2022-211', Anonymous Referee #1, 24 Nov 2022 reply

Heather Christine Regan et al.

Heather Christine Regan et al.

Viewed

Total article views: 318 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
228 84 6 318 1 1
  • HTML: 228
  • PDF: 84
  • XML: 6
  • Total: 318
  • BibTeX: 1
  • EndNote: 1
Views and downloads (calculated since 01 Nov 2022)
Cumulative views and downloads (calculated since 01 Nov 2022)

Viewed (geographical distribution)

Total article views: 310 (including HTML, PDF, and XML) Thereof 310 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 08 Dec 2022
Download
Short summary
Multiyear ice (MYI), sea ice that survives the summer, is more resistant to changes than younger ice in the Arctic, so is a good indicator of sea ice resilience. We use a model with a new way of tracking MYI to assess the contribution of different processes affecting MYI. We find two important years for MYI decline: 2007, when dynamics are important, and 2012, when melt is important. These affect MYI volume and area in different ways, which is important for interpretation of observations.