
Accession Number : ADA326047
Title : Dynamics of the Bottom Boundary Layer on the Northern California Shelf,
Corporate Author : WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
Personal Author(s) : Trowbridge, J. H. ; Lentz, S. J.
PDF Url : ADA326047
Report Date : 31 DEC 1996
Pagination or Media Count : 60
Abstract : Timeseries measurements of velocity, temperature and conductivity on the northern California shelf during two winter seasons permit an observational test, in vertically integrated form, of a simple set of subinertial momentum and heat balances for the bottom boundary layer, which have resulted from recent theoretical work. These are: (1) an alongisobath momentum equation that reduces to a classical Ekman balance; (2) a crossisobath momentum equation in which the Ekman balance is modified by a buoyancy force caused by distortion of the isopycnal surfaces within the boundary layer; and (3) a heat balance in which variability of temperature is produced by crossisobath advection. The measurements confirm the importance of buoyancy in the crossisobath momentum equation, and, as has recently been predicted theoretically, they indicate that buoyancy is a dominant effect when the boundary layer is thick, which typically occurs during downwellingfavorable flows. An Ekman balance describes subinertial fluctuations in the alongisobath momentum equation with moderate success. The mean alongisobath momentum equation is significantly influenced by a buoyancy force caused by an alongisobath temperature gradient, and alongisobath advection is as important as crossisobath advection in the heat balance. Thus alongisobath variability of temperature, which has been neglected in most theoretical work, is fundamental to the structure of the velocity field and the evolution of the temperature field.
Descriptors : *MATHEMATICAL MODELS, *BOUNDARY LAYER, *COMPUTATIONAL FLUID DYNAMICS, *HEAT BALANCE, *MOMENTUM, VELOCITY, DYNAMICS, TURBULENT BOUNDARY LAYER, WINTER, CALIFORNIA, OCEAN BOTTOM, BUOYANCY, BALANCES, SEASONS.
Subject Categories : Physical and Dynamic Oceanography
Fluid Mechanics
Numerical Mathematics
Distribution Statement : APPROVED FOR PUBLIC RELEASE