Differential Sea-Ice Drift. II. Comparison of Mesoscale Strain Measurements to Linear Drift Theory Predictions
- 1 January 1974
- journal article
- research article
- Published by Cambridge University Press (CUP) in Journal of Glaciology
- Vol. 13 (69), 457-471
- https://doi.org/10.1017/s0022143000023224
Abstract
A comparison of mesoscale strain measurements with the atmospheric pressure field and the wind velocity field indicate that the ice divergence rate and vorticity follow the local pressure and wind divergence with significant correlation. For low atmospheric pressures and converging winds the divergence rate was found to be negative with the vorticity being counter-clockwise. The inverse behavior was observed for high pressures and diverging winds. This behavior was shown to agree with predictions based upon the infinite boundary solution of a linearized drift theory in the absence of gradient current effects and using the constitutive law proposed by Glen (1970) for pack ice. The best least-squares values of the constitutive law parametersηandζwere found to be ≈ 1012kg/s. Using typical divergence rates these values yield compressive stresses of the magnitude of 105N/m which are similar to values suggested by the Parmerter and Coon (1972) ridge model. In general, the infinite boundary solution of the linear drift equation indicates that in a low-pressure region that is reasonably localized in space, the ice would be expected to converge for high compactness (winter) and diverge for low compactness (summer).Calculations were also carried out using a more general linear visco-elastic constitutive law that includes memory effects and which includes a generalized Hooke’s law as well as the Glen law as special cases. A best fit of this more general calculation with strain measurements indicates overall a better agreement with viscous behavior than with elastic behavior, with the frequency behavior of the estimated “viscosities” similar to the Glen law behavior at temporal frequencies less than ≈ 0.01 h−1.Keywords
This publication has 5 references indexed in Scilit:
- Differential Sea-Ice Drift. I. Spatial and Temporal Variations in Sea-Ice DeformationJournal of Glaciology, 1974
- Mesoscale Strain Measurements on the Beaufort Sea Pack Ice (Aidjex 1971)Journal of Glaciology, 1973
- Model of pressure ridge formation in sea iceJournal of Geophysical Research, 1972
- The wind-driven circulation of ice and water in a polar oceanJournal of Geophysical Research, 1965
- The equilibrium drift of Ice Station AlphaJournal of Geophysical Research, 1962