HR: 15:10h
AN: OS43C-07    [Abstracts]
TI: Parameterizing Ocean Eddy Transports From Surface to Bottom
AU: * Aiki, H
EM: aiki@jamstec.go.jp
AF: Frontier Research Center for Global Change, JAMSTEC, Showamachi, Kanazawaku, Yokohama, 236-0001 Japan
AU: Jacobson, T
EM: tivon@eps.s.u-tokyo.ac.jp
AF: Department of Earth and Planetary Science, Univ of Tokyo, Hongo, Bunkyoku, Tokyo, 113-0033 Japan
AU: Yamagata, T
EM: yamagata@eps.s.u-tokyo.ac.jp
AF: Frontier Research Center for Global Change, JAMSTEC, Showamachi, Kanazawaku, Yokohama, 236-0001 Japan
AU: Yamagata, T
EM: yamagata@eps.s.u-tokyo.ac.jp
AF: Department of Earth and Planetary Science, Univ of Tokyo, Hongo, Bunkyoku, Tokyo, 113-0033 Japan
AB: To improve subgrid-scale physics of climate ocean models, in particular near the top and bottom boundaries, we consider new parameterization schemes for the extra transport velocity by waves and eddies in baroclinic instability. These come in the form of elliptic equations, previously unmentioned, which we derive for the eddy-induced overturning stream function. They guarantee decrease of the mean field potential energy. Our principal example gives a relationship between the vertical shear of the overturning velocity and the buoyancy torque of the main geostrophic current. Interestingly the parameterized velocity is nonsingular at the bottom and the sea surface, contrasting with the constant-coefficient Gent and McWilliams (1990)scheme. Idealized two-dimensional numerical experiments uccessfully reproduce meridional overturning circulation even when the background density gradient is uniform everywhere (the Eady problem) or when the bottom is steeply sloped. We further demonstrate that adding an eddy form drag (wave tress) term in the TRM momentum equations yields overturning of the velocity field.
DE: 4255 Numerical modeling
DE: 4520 Eddies and mesoscale processes
DE: 4532 General circulation
DE: 4568 Turbulence, diffusion, and mixing processes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting