Time-dependent Effects On Ridge Initiation In Sea Ice Leads

Coon, Max D.; Knoke, G.S.; Lau, Philipp

doi:10.1109/oceans.1989.587528

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…This equation is a good approximation to the average ridge building force and the viscoelastic-buckling load for a lead (for loads of six-hour duration). This is in good agreement with Parmerter and Coon (1973) (for friction of 0.3); Coon and Lau (1990); Coon et al (1989aCoon et al ( , 1989b.…”

Section: Report Documentation Pagesupporting

confidence: 85%

Sea Ice Mechanics Research

Coon¹

1999

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LONG-TERM GOALThe ultimate goal of this research is the development of a complete ice dynamics model that will include lead direction and ice thickness distribution in refrozen leads. OBJECTIVESNorthWest Research Associates, Inc. (NWRA) had two objectives during this past year. The first was to use stress data to develop a new formulation of ice strength to be used in the anisotropic model . The new formulation was developed and has been provided to Dr. R. S. Pritchard for his use in model development for PIPS3.0. The second objective for this year was to review other work being done on sea ice strength in Europe. APPROACHThe approach this year was to use measured sea ice stress and models to formulate the behavior of refrozen leads. Some of the data in the models was acquired by visits to several European universities. These visits were accomplished through an appointment as Adjunct Scientist to the International ONR Office in London. WORK COMPLETEDThe work with SIMI stress data analysis was completed and the results were presented in a paper, "Determination of Pack Ice Stress from Flatjack Sensors," submitted to the Journal of Cold Regions Science and Technology. Douglas C. Echert, Gerald S. Knoke and myself authored this paper. Important insight into sea ice strength was gained through visits to the Technical Universities of Denmark, Finland, and Norway, as well as a visit to the Scott Polar Institute of Cambridge University in England. On each visit, I made a presentation on the development of the Anisotropic Sea Ice Model and received useful review of the model. The findings from the visits are presented in the section below. The results of this year's work were also presented at the PIPS3.0 development meeting at NIC in July. RESULTSDuring my six-month visit to the Technical University of Denmark, I worked with Leif Toudal on a frazil/pancake ice model for the Greenland Sea that may have applications in support of PIPS3.0 for

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Section: Report Documentation Pagesupporting

confidence: 85%

Sea Ice Mechanics Research

Coon¹

1999

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“…The tensile strength is near zero. The compressive strength can be estimated from theories, numerical models [Hopkins, 1994], laboratory data, and field data for buckling [Coon et al, 1989], rafting [Pritchard et al, 1995], and ridging [Parmerter and Coon, 1972] of lead ice. The shear strength can be estimated from buckling and the shear strength of rubble ice [Weiss et al, 1981;Coon et al, 1995b].…”

Section: Isotropic Icementioning

confidence: 99%

The architecture of an anisotropic elastic‐plastic sea ice mechanics constitutive law

Coon¹,

Knoke²,

Echert³

et al. 1998

J. Geophys. Res.

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Abstract. The architecture for a new large-scale anisotropic constitutive law intended for use in a sea ice dynamics model is presented here. This architecture accounts directly for refrozen lead systems in the pack ice strength (with an anisotropic failure surface) and in the ice thickness distribution (with an oriented thickness distribution). The lower limit (5 km) of the model resolution is controlled by the fracture spacing of old, thicker ice and the maximum lead width. The upper limit of the model resolution (100 km) is controlled by curvature in the lead directions and variations in the lead width. These, in turn, are controlled by the variations in internal ice stress due to driving forces (winds and currents), which set the time resolution. This architecture features abrupt changes in the failure surface and the associated flow rule that cannot be averaged over a time step. In addition, the principal stress normal to a new lead must be zero as it opens. This model has subscale simulations that allow for the inclusion of phenomena such as ridging, rafting, buckling, and fracture on the behavior of the ice. With this new ice constitutive law, it is possible to test directly the ice failure strength, plastic flow rule, and ice thickness distribution. The data most useful for this testing come from ice stress and position buoys together with synthetic aperture radar deformation data. Some data comparisons have already been made.

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US research in ice mechanics: 1987–1990

Richter‐Menge

1992

Cold Regions Science and Technology

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Time-dependent Effects On Ridge Initiation In Sea Ice Leads

Cited by 5 publications

References 3 publications

Sea Ice Mechanics Research

Sea Ice Mechanics Research

The architecture of an anisotropic elastic‐plastic sea ice mechanics constitutive law

US research in ice mechanics: 1987–1990

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