Impact of variable atmospheric and oceanic form drag on simulations of Arctic sea ice
Impact of variable atmospheric and oceanic form drag on simulations of Arctic sea ice
Over Arctic sea ice, pressure ridges and floe and melt pond edges all introduce discrete obstructions to the flow of air or water past the ice and are a source of form drag. In current climate models form drag is only accounted for by tuning the air–ice and ice–ocean drag coefficients, that is, by effectively altering the roughness length in a surface drag parameterization. The existing approach of the skin drag parameter tuning is poorly constrained by observations and fails to describe correctly the physics associated with the air–ice and ocean–ice drag. Here, the authors combine recent theoretical developments to deduce the total neutral form drag coefficients from properties of the ice cover such as ice concentration, vertical extent and area of the ridges, freeboard and floe draft, and the size of floes and melt ponds. The drag coefficients are incorporated into the Los Alamos Sea Ice Model (CICE) and show the influence of the new drag parameterization on the motion and state of the ice cover, with the most noticeable being a depletion of sea ice over the west boundary of the Arctic Ocean and over the Beaufort Sea. The new parameterization allows the drag coefficients to be coupled to the sea ice state and therefore to evolve spatially and temporally. It is found that the range of values predicted for the drag coefficients agree with the range of values measured in several regions of the Arctic. Finally, the implications of the new form drag formulation for the spinup or spindown of the Arctic Ocean are discussed.
geographic location/entity, arctic, sea ice, Atm/ocean structure/phenomena, ekman pumping, models and modeling, climate models, ocean models, parameterization
1329-1353
Tsamados, Michel
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Feltham, Daniel L.
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Schroeder, David
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Flocco, Daniela
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Farrell, Sinead L.
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Kurtz, Nathan
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Laxon, Seymour W.
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Bacon, Sheldon
1e7aa6e3-4fb4-4230-8ba7-90837304a9a7
May 2014
Tsamados, Michel
c206a0fe-e2c2-4853-9d71-4d3d9c882af5
Feltham, Daniel L.
319e6819-8a82-47e0-a22e-9d496d35b7ad
Schroeder, David
60a22a99-a7c1-4a47-88ff-cb00834edf15
Flocco, Daniela
9878e3a9-c3c9-4cce-8730-0eb2586c8630
Farrell, Sinead L.
33710b51-9f03-4cc4-b73f-9d38e172ae34
Kurtz, Nathan
fb8b00a8-7868-40c3-b468-1d2d8487764a
Laxon, Seymour W.
9626beb4-a30c-4159-863a-7cfc745067f6
Bacon, Sheldon
1e7aa6e3-4fb4-4230-8ba7-90837304a9a7
Tsamados, Michel, Feltham, Daniel L., Schroeder, David, Flocco, Daniela, Farrell, Sinead L., Kurtz, Nathan, Laxon, Seymour W. and Bacon, Sheldon
(2014)
Impact of variable atmospheric and oceanic form drag on simulations of Arctic sea ice.
Journal of Physical Oceanography, 44 (5), .
(doi:10.1175/JPO-D-13-0215.1).
Abstract
Over Arctic sea ice, pressure ridges and floe and melt pond edges all introduce discrete obstructions to the flow of air or water past the ice and are a source of form drag. In current climate models form drag is only accounted for by tuning the air–ice and ice–ocean drag coefficients, that is, by effectively altering the roughness length in a surface drag parameterization. The existing approach of the skin drag parameter tuning is poorly constrained by observations and fails to describe correctly the physics associated with the air–ice and ocean–ice drag. Here, the authors combine recent theoretical developments to deduce the total neutral form drag coefficients from properties of the ice cover such as ice concentration, vertical extent and area of the ridges, freeboard and floe draft, and the size of floes and melt ponds. The drag coefficients are incorporated into the Los Alamos Sea Ice Model (CICE) and show the influence of the new drag parameterization on the motion and state of the ice cover, with the most noticeable being a depletion of sea ice over the west boundary of the Arctic Ocean and over the Beaufort Sea. The new parameterization allows the drag coefficients to be coupled to the sea ice state and therefore to evolve spatially and temporally. It is found that the range of values predicted for the drag coefficients agree with the range of values measured in several regions of the Arctic. Finally, the implications of the new form drag formulation for the spinup or spindown of the Arctic Ocean are discussed.
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Published date: May 2014
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Keywords:
geographic location/entity, arctic, sea ice, Atm/ocean structure/phenomena, ekman pumping, models and modeling, climate models, ocean models, parameterization
Organisations:
Marine Physics and Ocean Climate
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Local EPrints ID: 364941
URI: http://eprints.soton.ac.uk/id/eprint/364941
ISSN: 0022-3670
PURE UUID: 37c92647-e069-47f0-95f3-b8f8163ed034
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Date deposited: 15 May 2014 10:35
Last modified: 14 Mar 2024 16:43
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Author:
Michel Tsamados
Author:
Daniel L. Feltham
Author:
David Schroeder
Author:
Daniela Flocco
Author:
Sinead L. Farrell
Author:
Nathan Kurtz
Author:
Seymour W. Laxon
Author:
Sheldon Bacon
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