Estimation of boundary values in a North Atlantic circulation model using an adjoint method

Ayoub, Nadia

doi:10.1016/j.ocemod.2005.06.003

Cited by 22 publications

(26 citation statements)

References 29 publications

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“…While uncertainty estimates for the model and the observations are imperfect, remaining misfits in the Southern Ocean state estimate primarily result from the need for more iterations to be carried out. Previous state estimates have taken on the order of 75 Ayoub, 2006) iterations to converge.…”

Section: Discussionmentioning

confidence: 99%

“…(Lu et al;. Topography is very influential to circulation, especially in energetic regions like the Southern Ocean (Losch and Wunsch;2003;Losch and Heimbach;2006). Third, the choice of eddy parameterizations has been shown to have a great effect on the Drake Passage transport in numerical models Hallberg and Gnanadesikan; A dominant feature of the meridional overturning streamfunctions plotted in Section 6.3 is a significant cross-isopycnal flow over most depths and latitudes (see for example Figure (6-7)).…”

Section: Discussionmentioning

confidence: 99%

“…The MIT Ocean General Circulation Model (MITgcm) (Marshall, Adcroft, Hill, Perelman and Heisey;1997;1997;Adcroft et al;2006) is used to solve the HPEs on a "C" grid (Arakawa and Lamb;1977).…”

Section: The Forward Modelmentioning

confidence: 99%

“…As part of the ECCO consortium, Gaël Forget has determined a spatially varying uncertainty field for the in situ hydrographic data 2006). The field is a climatological error in the sense that it is based on binning the data and examining the standard deviation of the error within the bins.…”

Section: In Situ Datamentioning

confidence: 99%

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Production and analysis of a Southern Ocean state estimate

Mazloff¹

2006

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A modern general circulation model of the Southern Ocean with one-sixth of a degree resolution is optimized to the observed ocean in a weighted least squares sense. Convergence toward the state estimate solution is carried out by systematically adjusting the control variables (prescribed atmospheric state, initial conditions, and open northern boundary at 24.7 o S) using the adjoint method. A cost function compares the model state to data from CTD synoptic sections, hydrographic climatology, satellite altimetry, and XBTs. Costs attributed to control variable perturbations ensure a physically realistic solution. An optimized solution is determined by the weights placed on the cost function terms. The state estimation procedure, along with the weights used, is described. A significant result is that the adjoint method is shown to

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: The Forward Modelmentioning

confidence: 99%

Section: In Situ Datamentioning

confidence: 99%

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Production and analysis of a Southern Ocean state estimate

Mazloff¹

2006

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“…However, determination of OBCs remains as a great challenge due to scarceness of available observations and low resolution or accuracy of larger scale models. After the adjoint assimilation method was introduced into oceanography, many researchers explored feasibility and performance of the method in obtaining OBCs [1][2][3][4][5][6]. With the adjoint method, OBCs can be adjusted such that the simulation results come close to the available observations.…”

Section: Introductionmentioning

confidence: 99%

A Method for Inversion of Smooth Open Boundary Conditions

Pan¹,

Zheng²,

Lv³

2016

Proceedings of 2016 International Conference on Modeling, Simulation and Optimization Technologies and Applications (MSOTA2016)

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Parameter estimation for a three‐dimensional numerical barotropic tidal model with adjoint method

Zhang¹,

Lü²

2007

Numerical Methods in Fluids

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SUMMARYThe parameters of a three-dimensional (3-D) barotropic tidal model are estimated using the adjoint method. The mode splitting technique is employed in both forward and adjoint models. In the external mode, the alternating direction implicit method is used to discretize the two-dimensional depth-averaged equations and a semi-implicit scheme is used for the 3-D internal mode computations. In this model the bottom friction is expressed in terms of bottom velocity which is different from the previous works. Besides, the bottom friction coefficients (BFCs) are supposed to be spatially varying, i.e. the BFC at some grid points are selected as the independent BFC, while the BFC at the other grid points can be obtained through linear interpolation with these independent BFCs. On the basis of the simulation of M 2 tide in the Bohai and North Yellow Seas (BNYS), twin experiments are carried out to invert the prescribed distributions of model parameters. The parameters inverted are the Fourier coefficients of open boundary conditions (OBCs), the BFC and the vertical eddy viscosity profiles. In these twin experiments, the real topography of BNYS is installed. The 'observations' are produced by the tidal model and recorded at the position of TOPEX/Poseidon altimeter data, tidal gauge data and current data. The experiments discuss the influence of initial guesses, model errors and data number. The inversion has obtained satisfactory results and the prescribed distributions have been successfully inverted. The results indicate that the inversion of BFC is more sensitive to data error than that of OBC and the vertical eddy viscosity profiles.

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Estimation of boundary values in a North Atlantic circulation model using an adjoint method

Cited by 22 publications

References 29 publications

Production and analysis of a Southern Ocean state estimate

Production and analysis of a Southern Ocean state estimate

A Method for Inversion of Smooth Open Boundary Conditions

Parameter estimation for a three‐dimensional numerical barotropic tidal model with adjoint method

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