Turbulent stress at the ice/ocean interface and bottom surface hydraulic roughness during the SHEBA drift

摘要: [1] Upper ocean turbulence and mean current data from the 1997–1998 Surface Heat Budget of Arctic Ocean (SHEBA) drift in western were used to estimate turbulent shear stress at ice/ocean interface hydraulic roughness ice undersurface. Techniques for determining interfacial velocity covariance measurements boundary layer (IOBL) are complicated by buoyancy flux heterogeneity undersurface, where protrusions corresponding relatively small upper surface features become major obstacles when compared scale IOBL. In addition, deformation forced relocation main SHEBA oceanographic program about midway through experiment. Hence, there two different measurement sites consider. Three methods compute undersurface characterizing undeformed, multiyear floe occupied project. The first was straightforward (naive) application “law wall” instrument cluster nearest interface, assuming a logarithmic profile constant stress. For second method, local closure model entire IOBL order impact Coriolis attenuation forces on near boundary. A third proposed here time, estimated mixing length eddy viscosity inversely proportional wave number peak weighted vertical spectrum. last method appears most robust, that it shows no overall difference z0 between only minor seasonal directional differences. best site is 0.0048 m < 0.007, i.e., 6 mm. Specification regional “aggregate” under-ice requires additional consideration added drag isolated pressure keels edges, along with reduced smoother, newly frozen open water.