Sea-ice mass balance in the Arctic in a new ice—ocean coupled model: impact of sea ice deformations
Guillaume Boutin1, Einar Ólason1, Pierre Rampal2,1, Heather Regan1, Camille Lique3, Claude Talandier3, Laurent Brodeau2, Robert Ricker4
IICWG 22/03/2023
1. Nansen Environmental and Remote Sensing Center, Bergen, Norway
2. CNRS, Univ. Grenoble, Institut de Géophysique de l'Environnement, Grenoble, France
3. Univ. Brest, CNRS, IRD, Ifremer, Laboratoire d’Océanographie Physique et Spatiale (LOPS), Brest, France
4. NORCE, Tromsø, Norway
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Introduction
Breakup event in the Beaufort Sea (Feb. 2013)
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Introduction
Schematic by J. Rheinlænder
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To quantify this impact, we need to reproduce this heterogeneity in our models
Breakup event in the Beaufort Sea (Feb. 2013)
Introduction
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State-of-the-art sea ice models struggle to reproduce this heterogeneity
For resolution> 5km, modelled sea ice properties are very homogeneous
Sea ice model: neXtSIM
Ocean model: OPA (NEMO)
Simulations start in 1995 and stop end of 2018.
Horizontal resolution is 0.25deg (12km in the Arctic)
Landfast ice → Lemieux et al. 2015.
Plotting tools: Laurent Brodeau
CRACKS
Using a sea ice model with a brittle rheology
Solution:
Problem:
Introduction
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Can we get a good Arctic sea ice mass balance using a brittle rheology?
If yes, what is the impact of small-scale dynamics on this mass balance?
Changing rheology impacts:
- Large-scale motions (transport)
→ First order importance in the mass balance
Introduction
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Sea ice evaluation in the model
Shear rate on April 16th, 2007. (1/day)
The model compares very well against sea ice deformations from RGPS
This was the original objective of neXtSIM developers.
Can we do more than that?
Sea ice deformations
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Sea ice evaluation in the model
Sea ice volume evolution consistent with CS2SMOS, small negative bias against PIOMAS (not observations!) before 2008
Sea ice volume
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Sea ice evaluation in the model
OBS.
Winter sea ice thickness 2011-2017 climatology
MODEL
Ex: Sea ice thickness vs CS2SMOS
Spatial distribution is consistent ,
thickness magnitude is well captured!
[m]
[m]
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Daily Pan-Arctic sea ice drift speed from MODEL and OSI-SAF (OBS) over 2018
Good consistency with observations
Sea ice evaluation in the model
Ex: Sea ice drift speed
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Coverage:
Sea ice evaluation in the model
Winter mass balance:
Ricker et al., 2021
Total volume change = Dynamic change + Thermodynamic change
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Coverage:
Sea ice evaluation in the model
Winter mass balance:
Ricker et al., 2021
Total volume change = Dynamic change + Thermodynamic change
CS2/Envisat
(ESA CCI)
CS2/Envisat
+ monthly motions from merged radiometers & scatterometers (from CERSAT)
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Ricker et al., 2021
Sea ice evaluation in the model
Winter mass balance: dynamic change (import/export)
Coverage:
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Ricker et al., 2021
Sea ice evaluation in the model
Winter mass balance: dynamic change (import/export)
Coverage:
Variability is (generally) well captured!
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Sea ice evaluation in the model
Winter mass balance: thermodynamic change
Ricker et al., 2021
Coverage:
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Sea ice evaluation in the model
Winter mass balance: thermodynamic change
Ricker et al., 2021
Coverage:
The model does well for thermodynamics, and very well for dynamics!
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Impact of leads on winter ice production
Domain includes:
- Latitudes>81oN
- Depth > 300m
Ice formation in open water
(lateral growth)
November 2007 to March 2008
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2000-2018 climatology of the ratio of winter new thin ice production in open water to total ice production
Methodology:
Domain includes:
- Depth > 300m
- Latitudes>81oN in the Atlantic sector
Impact of leads on winter ice production
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2000-2018 climatology of the ratio of winter new thin ice production in open water to total ice production
Methodology:
Impact of leads is clearly visible in 18-year long climatology of winter ice production
Domain includes:
- Depth > 300m
- Latitudes>81oN in the Atlantic sector
Impact of leads on winter ice production
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Evolution of contribution of leads to total ice growth in winter (January to March)
20 to 30% of ice production takes place in leads! (and it’s going up)
We integrate in the Arctic Basin:
Selected domain:
Impact of leads on winter ice production
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Impact of leads on winter ice production
Contribution of leads & polynyas
to total winter ice growth [-]
No shelf (<300m)
Where does it matter the most?
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Impact of leads on winter ice production
Where does it matter the most?
Contribution of leads & polynyas
to total winter ice growth [-]
North of Fram Strait:
→ Break-up as sea ice flows out of the Arctic Basin
Beaufort Sea
→ Strong intermittent break-up events
(see 2013 event, Rheinlænder et al., 2022)
No shelf (<300m)
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Impact of leads on winter ice production
Where does it matter the most?
Contribution of leads & polynyas
to total winter ice growth [-]
Deep + shelf
No shelf
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Impact of leads on winter ice production
Where does it matter the most?
Contribution of leads & polynyas
to total winter ice growth [-]
Deep + shelf
No shelf
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Impact of leads on winter ice production
Where does it matter the most?
Contribution of leads & polynyas
to total winter ice growth [-]
Deep + shelf
Very important at the coast→ Role of coastal polynyas!
No shelf
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Impact of leads on winter ice production
Where is it increasing?
Contribution of leads & polynyas
to total winter ice growth [-]
Leads: increases everywhere, only significant in the Chukchi Sea
No shelf (<300m)
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Impact of leads & polynyas on winter ice production
Where is it increasing?
Contribution of leads & polynyas
to total winter ice growth [-]
Leads & polynyas: In the Arctic marginal Seas, mostly in the western part of the Arctic.
Mostly on the shelf!
→ Importance of coastal polynyas (and landfast ice)
No shelf
Deep + shelf
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There is more to explore!
Impact of leads on winter ice production
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Conclusion
Can we get a good Arctic sea ice mass balance using a brittle rheology?
If yes, what is the impact of small-scale dynamics on this mass balance?
Yes, we can (and we do).
From January to March, ~30% sea ice production takes place in leads.
This contribution is increasing (whereas total ice production is not)
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Interested in our work?
G.Boutin et al.: Modelling of wave-ice interactions: impact on ice dynamics
The end
Beaufort Breakup event:
Rheinlænder, J. W., Davy, R., Ólason, E., Rampal, P., Spensberger, C., Williams, T. D., et al. (2022). Driving mechanisms of an extreme winter sea ice breakup event in the Beaufort Sea. Geophysical Research Letters, 49, e2022GL099024. https://doi.org/10.1029/2022GL099024
This work:
Boutin, G., Ólason, E., Rampal, P., Regan, H., Lique, C., Talandier, C., Brodeau, L., and Ricker, R.: Arctic sea ice mass balance in a new coupled ice–ocean model using a brittle rheology framework, The Cryosphere, 17, 617–638, https://doi.org/10.5194/tc-17-617-2023, 2023.
Publications: