Turbulent Structure of the Surface Boundary Layer in an Ice-Covered Ocean.
WASHINGTON UNIV SEATTLE DEPT OF OCEANOGRAPHY
Pagination or Media Count:
Flow in the boundary layer under Arctic ice was measured in March 1970, in March-April 1971, and again in March-April 1972 using a number of specially designed four cm diameter current meters capable of resolving velocity component fluctuations up to five Hz. These meters were attached to instrument masts in orthogonal triplets at six or more depths beneath the ice. Mean and fluctuating velocity components were calculated for each of the instrument locations. The current field filtered with a 40 minute running average was found to be unsteady and to reflect the ice drift and wind velocities. During storms the 1971 data reveal a right-handed Ekman spiral to 16m. Below 16m the Ekman spiral sometimes continues in the proper direction and sometimes reverses. A steadier spiral is shown in the 1972 measurements. Turbulent intensities and Reynolds stresses, calculated from the fluctuating velocity field, generally reflect the structure of the density and mean velocity fields. The boundary layer examined in the 1972 experiment was unstable and downware flux of horizontal momentum was due primarily to brine driven convection.
- Physical and Dynamic Oceanography
- Snow, Ice and Permafrost