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John Marshall, David Ferreira, J-M. Campin, and Daniel Enderton

, 1891 – 1910 . Frankignoul , C. , A. Czaja , and B. L’Heveder , 1998 : Air–sea feedback in the North Atlantic and surface boundary conditions for ocean models. J. Climate , 11 , 2310 – 2324 . Gent , P. R. , and J. C. McWilliams , 1990 : Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr. , 20 , 150 – 155 . Gill , A. E. , J. S. A. Green , and A. J. Simmons , 1974 : Energy partition in the large-scale ocean circulation and the production of midocean eddies

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Yohai Kaspi and Glenn R. Flierl

parameter, g ′ is the reduced gravity, and D n is the layer depth. For future notation we denote the full potential vorticity in each layer as We will assume the simplest basic state with a uniform flow in each layer, The total streamfunction is composed of the mean part (4) and a perturbation and the equation for the perturbation streamfunction is where is the perturbation potential vorticity and J ( ϕ n , q n ) is the Jacobian of streamfunction and potential vorticity. The boundary conditions

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D. G. Dritschel and M. E. McIntyre

well be bound up with variations in the radiation-stress field related to variations in Rossby wave excitation and dispersion. The experiment shown here is conducted in a channel of nondimensional width and length 2 π with L D = 1. Free-slip boundary conditions apply at y = ± π , and the flow is periodic in x (see Benilov et al. 2004 for the use of the CASL algorithm in this geometry). The initial quasigeostrophic PV field q is built from a random anomaly field q ′ of maximum amplitude

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P. H. Haynes, D. A. Poet, and E. F. Shuckburgh

the right-hand side is determined by the average PV set by the initial condition. Recall that in the simulations shown here β is taken to be 0.5. Given the time-periodic topographic forcing defined by (5) , this defines a new kinematic problem in which the flow is time periodic and given by the solution of (6) subject to the boundary conditions. Analysis of the transport and mixing properties in this new kinematic problem show that a very large proportion of the domain is filled by a single

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Cegeon J. Chan, R. Alan Plumb, and Ivana Cerovecki

is followed by the correct phase at least 64% of the time; for example, the conditions prior to the onset of Phase A were correctly described to be in Phase D 64% of the time and incorrectly by Phase B or C 36% of the time. Similarly, Phase A described the PC space prior to Phase B 85% of the time. This shows that these preconditions are not symmetric, for example, there is a stronger relation between Phase A and Phase B than there is between Phase D and Phase A. Given the results in Table 2

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Peter L. Read, Yasuhiro H. Yamazaki, Stephen R. Lewis, Paul D. Williams, Robin Wordsworth, Kuniko Miki-Yamazaki, Joël Sommeria, and Henri Didelle

(at which frictional and dynamical time scales are roughly comparable) and the Rhines scale, though for other conditions the scale selection mechanism is less clear (see, e.g., Sukoriansky et al. 2007 ). While such models can provide useful and interesting insights into possible mechanisms for banded flows, they are highly idealized and take little account of the vertical structure of realistic geophysical fluid systems. It is sometimes difficult, therefore, to relate results from such studies

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Gang Chen, Isaac M. Held, and Walter A. Robinson

surface, as in HS94 . The model is run at T42 and T85 horizontal resolutions with 20 equally spaced sigma levels in the vertical. The model output is sampled daily, and the time-averaged results are averaged over the last 1600 days of 2000-day integrations. In the HS94 formulation, the boundary layer in the momentum equation is simply represented by linear Rayleigh damping in the lower troposphere. The vertical structure of the damping rate is prescribed, decreasing linearly from its value at the

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M. L. R. Liberato, J. M. Castanheira, L. de la Torre, C. C. DaCamara, and L. Gimeno

, υ ), the earth’s radius a , the angular speed of the earth’s rotation Ω, the specific gas constant R , and the ratio k of the specific gas constant to the specific heat at constant pressure. As model boundary conditions, it is assumed that ω = dp / dt vanishes as p → 0 and that the linearized geometric vertical velocity w = dz / dt vanishes at a level of constant pressure, p s , near the earth’s surface. The free oscillations (i.e., the normal modes) of the linearized primitive

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Yasuko Hio and Shigeo Yoden

SH. The wave–wave interaction between the stationary “planetary wave of zonal wavenumber 1” (hereafter denoted as “Wave 1”) and eastward propagating Wave 2 was investigated in HY04 with the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) reanalysis dataset over 20 years. The stationary Wave 1 is generated in the troposphere mainly by zonally asymmetric lower boundary conditions and has significant interannual variations ( Hio and Hirota 2002

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Yoshi-Yuki Hayashi, Seiya Nishizawa, Shin-ichi Takehiro, Michio Yamada, Keiichi Ishioka, and Shigeo Yoden

are suitable for the occurrence of critical latitude absorption there, which contributes to the easterly angular-momentum accumulation in those latitudes. Figure 2 is an example of comparison between weak-nonlinear and full-nonlinear evolutions of zonal mean angular momentum starting from one of the initial conditions utilized by Yoden and Yamada (1993) . Once the easterly acceleration is initiated in the polar region, it continues steadily. The nonlinear and the weak-nonlinear evolutions of

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