Description / Table of Contents:
CONTENTS: Preface. - Introduction. - Part 1:Mesoscale strain measurements on the Beaufort Sea pack ice. - Abstract. - Introduction. - Previous work. - Site location. - Results. - Correlation of synoptic aerial photography with measured strains. - Correlation of estimated wind stress and strain. - Conclusions. - Literature cited. - Part II: Structure of a multiyear pressure ridge. - Abstract. - Introduction. - Profiles. - Internal properties. - Largest ridge sail. - Conclusions. - Literature cited. - Part III: Top and bottom roughness of a multiyear ice floe. - Abstract. - Introduction. - Results. - Literature cited. - Part IV:Airphoto analysis of ice deformation in the Beaufort Sea Abstract. - Introduction. - Study area. - Method of analysis. - Ice deformations. - Net deformational changes. - Pressure ridge distribution. - Summary and conclusions. - Literature cited. - Part V: Data on morphological and physical characteristics of sea ice in the Beaufort Sea.
Description / Table of Contents:
The report is in five parts. Part I, Mesoscale Strain Measurements on the Beaufort Sea Pack Ice: Fracture (lead and crack) orientations in first-year ice indicate correlation with the orientation of the strain rate ellipse. A qualitative relation is suggested between the fracture density and the long-term divergence rate. Correlation was also observed between the divergence of the wind field, as computed from the surface pressure field, and the ice divergence. Part II, Structure of a Multiyear Pressure Ridge: Three transverse profiles were measured across a ľarge pressure ridge in the Beaufort Sea. The ridge sail extended 4 m above sea level and the keel 13 m below. The cross sections of the keel were roughly semicircular, suggesting that form drag coefficients for flow transverse to the long axes of multiyear ridges may be as high as 0.8. Part III, Top and Bottom Roughness of a Multiyear Ice Floe: A spectral study of the snow and ice topography of a multiyear floe showed that the snow cover attenuates the roughness amplitude of the ice surface but does not cover it completely. The snow surface variance is lower than the ice surface variance by a factor of 1/3 to 1/4. The correlation between snow and ice surface roughness is significant for long wavelengths (〉 8 m) but not for short wavelengths (〈 4 m). The ice sheet as a whole is in free-floating, isostatic equilibrium, but pronounced local deviations from isostatic equilibrium are common. Part IV, Air Photo Analysis of Sea Ice Deformation in the Beaufort Sea: The time, direction and magnitude of deformational motion were determined by combining observations of the changes in features related to ice deformation (leads, fractures, pressure ridges) with mesoscale measurements of strains and strain rates on the ice. Part V, Data on Morphological and Physical Characteristics of Sea Ice in the Beaufort Sea: Measurements of the size of ice blocks in newly formed pressure ridges and measurements of salinity and temperature are presented.
Type of Medium:
Series available for loan
iii, 66 S. : Ill., graph. Darst., Kt.
Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 315