HR: 14:20h
AN: OS52G-02    [PDF]
TI: Direct covariance measurements of turbulent Reynolds shear stresses beneath a wind-driven, wavy, sea surface
AU: * Trowbridge, J H
EM: jtrowbridge@whoi.edu
AF: Woods Hole Oceanographic Institution, 98 Water Street, Woods Hole, MA 02543 United States
AU: Terray, E A
EM: eterray@whoi.edu
AF: Woods Hole Oceanographic Institution, 98 Water Street, Woods Hole, MA 02543 United States
AU: Fredericks, J J
EM: jfredericks@whoi.edu
AF: Woods Hole Oceanographic Institution, 98 Water Street, Woods Hole, MA 02543 United States
AB: An important objective of CBLAST-low is to obtain direct covariance measurements of turbulent Reynolds shear stresses beneath a wind-driven, wavy, sea surface, in order to identify and quantify effects of shear, stratification, breaking surface waves, and Langmuir circulations. Direct covariance measurements of Reynolds shear stresses are difficult just beneath the air-sea interface because of irrotational motions produced by surface waves, which dominate the variance but do not transmit a Reynolds shear stress. During CBLAST-low, a horizontal array of near-surface velocity sensors, spanning scales between 1.5 and 9.0 m, was used to separate irrotational wave motions from turbulence, by capitalizing on the differences in spatial scales and propagation speeds of these two types of velocity fluctuations. The validity of the stress estimates is investigated by means of along-isobath and cross-isobath momentum balances, including air-side and water-side turbulent Reynolds shear stresses, local and Coriolis accelerations, and baroclinic and barotropic pressure gradients. Estimates of the spatial scales of the stress-carrying oceanic motions are obtained, and a preliminary evaluation of the roles of shear, stratification, breaking waves, and Langmuir circulations is presented.
DE: 4504 Air/sea interactions (0312)
DE: 4568 Turbulence, diffusion, and mixing processes
DE: 4572 Upper ocean processes
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting