Inverse 3D shallow water flow modelling of the continental shelf

Heemink, A.W.; Mouthaan, E.E.A.; Roest, Mark R.; Vollebregt, Edwin A. H.; Robaczewska, K.B.; Verlaan, Martin

doi:10.1016/s0278-4343(01)00071-1

Cited by 80 publications

(77 citation statements)

References 9 publications

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“…This model initially showed an error of up to two hours in the timing of high tide. A phase error (of varying magnitude) is consistently found in depth-averaged and 3D models of varying types (Bourban 2012, Heemink 2002, Cazenave 2012 when modelling this region. The aim of this paper is to find the cause of the tidal phase error.…”

Section: Introductionmentioning

confidence: 74%

“…The model tide is slightly out of phase at Aberdeen and the phase error grows as the tide propagates south down the North Sea finally becoming greatest at Lowestoft and Harwich where model high tide occurs two hours before the observed high tide. Several other models (depth-averaged and 3D) display a phase error of varying magnitude in the Southern Bight (Bourban 2012, Heemink 2002, Cazenave 2012. To investigate the problem further a tidal harmonic analysis was performed and the model was compared to observations across the shelf; the results for the principal component M 2 are shown in Figure 3.…”

Section: Model Validationmentioning

confidence: 99%

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The Importance of Long Wave Reflections in Tidal Modelling on a Continental Shelf

Luxford

Stansby

Rogers

2014

Int. Conf. Coastal. Eng.

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This paper investigates the tidal phase error found in a 2-D hydrodynamic model of the Southern Bight of the European continental shelf; an error also found in other models of the region. After identifying the predominant mechanisms controlling the tidal flow in the Southern Bight: bathymetry, bottom friction and coastline reflections, analysis of each mechanism is made. Sensitivity to bathymetry is tested, to bed friction using values based on physical bed properties and to coastline reflection of tidal waves by comparing standing/propagating wave analysis from model results with observations. It was found that using more physically realistic friction values improved the prediction of tidal amplitudes but had minimal effect on tidal phase and an unrealistic reduction in the bathymetry level would be required to correct the phase error. However analysis of tidal reflections revealed that the model under-predicts the amplitude of the reflected wave which may cause the erroneous phase pattern. It is proposed that the reflectiveness of the coastline has increased over time due to the cumulative effect of coastal engineering such as sea walls and barrages reducing energy dissipation. It is concluded that more attention needs to be given to the representation of coastlines in models; something which is currently neglected in model calibrations which focus on changing the bathymetry, bottom friction and boundary conditions to achieve the best model fit. It is suggested that the modelling of this process needs to be improved, especially when calculating long-term sediment transport from the hydrodynamic predictions where residual velocities are important and of small magnitude relative to velocity amplitudes.

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Section: Introductionmentioning

confidence: 74%

Section: Model Validationmentioning

confidence: 99%

The Importance of Long Wave Reflections in Tidal Modelling on a Continental Shelf

Luxford

Stansby

Rogers

2014

Int. Conf. Coastal. Eng.

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“…The control parameters might be model initial conditions or model parameters (Thacker and Long 1988). A sizeable amount of research on adjoint parameter estimation was carried out in the last 30 years in fields such as meteorology, petroleum reservoirs, and oceanography for instance by Seinfeld and Kravaris (1982), Bennet and Mcintosh (1982), Ulman and Wilson (1998), Courtier and Talagrand (1990), Lardner et al (1993) and Heemink et al (2002). A detailed description of the application of the adjoint method in atmosphere and ocean problems can be found in Navon (1998).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous perturbation stochastic approximation for tidal models

et al. 2011

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The Dutch continental shelf model (DCSM) is a shallow sea model of entire continental shelf which is used operationally in the Netherlands to forecast the storm surges in the North Sea. The forecasts are necessary to support the decision of the timely closure of the moveable storm surge barriers to protect the land. In this study, an automated model calibration method, simultaneous perturbation stochastic approximation (SPSA) is implemented for tidal calibration of the DCSM. The method uses objective function evaluations to obtain the gradient approximations. The gradient approximation for the central difference method uses only two objective function evaluation independent of the number of parameters being optimized. The calibration parameter in this study is the model bathymetry. A number of calibration experiments is performed. The effectiveness of the algorithm is evaluated in terms of the accuracy of the final results as well as the computational costs required to produce these results. In doing so, comparison is made with a traditional steepest descent method and also with a newly developed proper orthogonal decompositionbased calibration method. The SPSA method gives comparable results to steepest descent method with little computational cost. (2) The SPSA method with little computational cost can be used to estimate large number of parameters.

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“…For the global tidal simulation of FES94.1, Le Provost et al (1994) took a friction coefficient of 0.003 in the pelagic areas of the ocean surface and 0.0025 in the shallow water ones. Third, the BFC are supposed to be spatially varying Lardner 1991, 1992;Ullman and Wilson 1998;Heemink et al 2002). Lardner (1991, 1992) inverted the position dependent drag coefficients and water depth by assimilating sea level observations at a number of tidal stations.…”

Section: Introductionmentioning

confidence: 99%

“…Ullman and Wilson (1998) studied the spatial variability of the BFC by assimilating the ADCP data into a tidal model of the lower Hudson estuary with the adjoint method. Heemink et al (2002) developed an inverse 3D shallow water flow model in which the spatially varying friction parameters were estimated and the independent BFC were selected by analyzing the parameter gradient per grid point. The first two methods have been widely used in the tidal simulations, but the accuracy is relatively low.…”

Section: Introductionmentioning

confidence: 99%

On the Simulation of M2 Tide in the Bohai, Yellow, and East China Seas with TOPEX/Poseidon Altimeter Data

Zhang¹,

Lü²

2008

Terr. Atmos. Ocean. Sci.

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The M 2 tide in the Bohai, Yellow, and East China Seas (BYECS) is simulated by assimilating the TOPEX/Poseidon altimetry data with the adjoint method. The bottom friction coefficients (BFC) are supposed to be spatially varying. In this paper, the BFC at some grid points are chosen as the independent BFC and the BFC at the other grid points can be obtained through linear interpolation with these independent BFC. The independent BFC are selected uniformly over each 1° × 1° area and 120 independent BFC are obtained. Twin and practical experiments are carried out to discuss the spatially varying BFC. The results of twin experiments demonstrate that the adjoint method has a strong ability of inverting the prescribed BFC distributions combined with the spatially varying BFC. The prescribed BFC distributions are all successfully inverted. In practical experiments, the simulation precision has been highly increased by optimizing the spatially varying independent BFC. Three amphidromic points and a degenerate one appear in the cotidal charts of M 2 tide and the results coincide with the observed M 2 tide in BYECS fairly well.

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Inverse 3D shallow water flow modelling of the continental shelf

Cited by 80 publications

References 9 publications

The Importance of Long Wave Reflections in Tidal Modelling on a Continental Shelf

The Importance of Long Wave Reflections in Tidal Modelling on a Continental Shelf

Simultaneous perturbation stochastic approximation for tidal models

On the Simulation of M2 Tide in the Bohai, Yellow, and East China Seas with TOPEX/Poseidon Altimeter Data

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