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Arnaud Czaja and John Marshall

than its two-dimensional atmospheric counterpart in which there is a single overturning cell in each hemisphere, see Fig. 4 . Analysis of the mean thickness of the θ O layers reveals (not shown) that the warm cells occupy a volume of fluid with high stratification (thin layers) and can be identified with the mass circulation within the ventilated thermoclines of the Southern and Northern Hemispheres. This is further confirmed by the fact that their poleward extension is rather well predicted by

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Zhengyu Liu

deformation radius, with g'TABLE 1. Standard parameters used in scaling analysis.Parameter Meaning Value~ Mean SST gradient 1 -C/100 kmQE Mean evaporation 200 W m-20 Mean zonal wind 10 m s-~h~, Mean mixed-layer depth 100 mho Mean thermocline 500 m depthL Meridional scale of the 1000 km disturbancecvHeat content 4. X 103 J (kg)-~ K-~p0 Density of water

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A. G. Marshall, O. Alves, and H. H. Hendon

from Fig. 4a is around 2 m s −1 , consistent with that reported by Bergman et al. (2001) . Vertical depth sections of anomalous temperature at the equator (not shown) also illustrate eastward propagation along the thermocline similar to that in Fig. 4a . This is associated with an anomalous reduction in the equatorial upwelling of cold water as the Kelvin waves propagate, affecting the meridional overturning circulation of the tropical Pacific Ocean, which is characterized by the equatorward

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C. J. Thompson

the thermocline depth along with its dynamically consistent upper-layer currents. In matrix form the model can be written where r and T are the r field and T field discretizations, respectively. Defining Given a set of initial conditions, the solution to this system is determined at any time by φ ( t ) = exp( M t )· φ (0), (2.3) where is called the propagator. LOAM computes the linear matrix operator, M , and the propagator explicitly. A second way to express the solution to (2.1) uses

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Daniel Enderton and John Marshall

ocean basins. There is a compensating eddy-driven circulation. The resulting “residual” overturning (discussed at length in Marshall et al. 2007 ) features strong subtropical cells (STCs) with a strength of some 60 Sv (Sv ≡ 10 6 m 3 s −1 ) ( Fig. 5 , top left). It is tempting to call them the ocean’s Hadley cells, although they are mechanically rather than thermally forced. Associated with this overturning circulation, the thermocline features two “lenses” of warm, salty fluid overlying much

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J. David Neelin

system governs the dynamics of a constant-density, reduced-gravity layer representing theocean above the thermocline, while the wind stress isdeposited into a shallower, fixed-depth mixed layer andmixed down into the remainder of the shallow waterlayer by interfacial friction representing turbulentmixing. This differential deposition of wind stress drivesa circulation within the shallow water layer which permits the model to reproduce equatorial upwelling andqualitative features of the equatorial

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Max J. Suarez and Paul S. Schopf

someunspecified nonlinear mechanism invoked to limit thegrowth of unstable perturbations. Its key element is theinclusion of the effects of equatorially trapped oceanicwaves propagating in a closed basin through a timedelayed term. This simple system has multiple stationary states which can all bycome unstable. When thishappens, solutions are self-sustained oscillations whoseperiod is at least twice as long as the assumed delay.We offer this model as an explanation for the resultsof simple circulation models

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Syukuro Manabe and Kirk Bryan

main thermocline. An extensive icepack with a thickness of 1-4 m forms in the northernpart of the ocean. In the final part of the calculation interaction between the atmosphere and the ocean is allowed. Sincedifferent types of fluid motion occur in the atmosphericand ocean models, the atmospheric model requiresapproximately 40 times more computation to integrateover a given time period as the ocean model. Accordingto the stage I results of the numerical integration of theatmospheric model, the

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Indrani Roy and Joanna D. Haigh

deny any of these mechanisms. The signal around the eastern tropical Pacific as seen in Fig. 4a might be associated with an intensification of the ITCZ, uplifting the thermocline and strengthening the Walker circulation. Clement et al. (1996), using a simplified climate model, show how ocean–atmosphere coupling produces a cooling in annual mean SSTs of the eastern Pacific in response to a uniform surface heating and it is plausible that this could be produced by solar heating. The modeling study

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Kirk Bryan and Michael D. Cox

,which has existed for over a century, as to whether windor differential heating is the primary factor in drivingthe ocean circulation. Up to the present these twofactors usually have been treated separately. Implicitin the thinking of many oceanographers about theocean circulation is a linear superposition of two solutions, one based on thermocline theory, and the otherbased on wind-driven theory. Due to important nonlinearities that exist in the more general mathematicalmodels of large-scale ocean

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