Sea Ice Thickness Distribution in the Arctic Ocean

Abstract

Structural characteristics of transitionally rough and fully rough turbulent boundary layers are presented. These were measured in flows at different roughness Reynolds numbers developing over uniform spheres roughness. Inner regions of the longitudinal component of normal Reynolds stress profiles and log regions of mean profiles continuously change in the transitionally rough regime, as the roughness Reynolds number, R e1,;v,aries. These properties asymptotically approach fully rough behaviour as Rek increa ses, and smooth behaviour at low R ek. Profiles of other Reynolds-strData from the unclassified literature were reviewed to determine the regional and seasonal distributions of sea ice thickness, pressure ridging statistics, frequency of occurrence of polynyas, and keel/sail height ratios. Seasonal and regional maps and histograms of these properties were constructed. The majority of the data were obtained from submarines equipped with a narrow-beam, upward-looking sonar. As determined from an analysis of 17 submarine cruises, the overall mean thickness of Arctic sea ice above 65° N, including both deformed and undeformed ice, is 2.9 m with a standard deviation of 1.8 m. The overall seasonal mean ranges from approximately 2.4 m in spring to 3.3 m in summer. Local mean ice drafts ranged from less than 1 m near the marginal ice zone to greater than 7 m to the north of the Canadian Archipelago. Histograms of sea ice draft reflect a bimodal distribution in winter and spring, an effect of the presence of thin first year ice. Due to ice melt in summer and autumn only a single mode of much thicker multiyear ice is observed.ess tensor components, turbulence kinetic energy, turbulence-kinetic-energy production , and the turbulence-kinetic-energy dissipation are also given, along with appropriate scaling variables. Fully rough, one-dimensional spectra of longitudinal velocity fluctuation s from boundary-layer inner regions are similar to smooth-wall results for k1 y > 0.2 when non-dimensionalized using distanc e from the wally as the length sca le, and (r / p )1⁄2as the velocity scale, where T is local shear stress, p is static density, and k1 is one-dimensional wavenumber in th e flow direction.