A numerical model of the North Sea and its use in choosing locations for the deployment of off-shore tide gauges in the JONSDAP '76 oceanographic experiment

1976 ◽  
Vol 29 (1) ◽  
pp. 11-24 ◽  
Author(s):  
A. M. Davies
Keyword(s):  
Numerical Model ◽  
North Sea ◽  
Tide Gauges ◽  
The North ◽  
The North Sea

Data assimilation with the ensemble Kalman filter in a numerical model of the North Sea

2016 ◽  
Vol 66 (8) ◽  
pp. 955-971 ◽  
Author(s):  
Stéphanie Ponsar ◽  
Patrick Luyten ◽  
Valérie Dulière
Keyword(s):  
Kalman Filter ◽  
Numerical Model ◽  
Data Assimilation ◽  
North Sea ◽  
Ensemble Kalman Filter ◽  
The North ◽  
The North Sea

Model-based hydrodynamic leveling; a power full tool to enhance the quality of the geodetic networks

2020 ◽  
Author(s):  
Yosra Afrasteh ◽  
Cornelis Slobbe ◽  
Martin Verlaan ◽  
Martina Sacher ◽  
Roland Klees
Keyword(s):  
North Sea ◽  
Water Levels ◽  
Offshore Platforms ◽  
Tide Gauges ◽  
Data Set ◽  
Model Based ◽  
The North ◽  
Height System ◽  
The North Sea ◽  
The Impact

<p>Model-based hydrodynamic leveling is an efficient and flexible alternative method to connect islands and offshore tide gauges with the height system on land. The method uses a regional, high-resolution hydrodynamic model that provides total water levels. From the model, we obtain the differences in mean water level (MWL) between tide gauges at the mainland and at the islands or offshore platforms, respectively. Adding them to the MWL relative to the national height system at the mainland’s tide gauges realizes a connection of the island and offshore platforms with the height system on the mainland. Usually, the geodetic leveling networks are based on spirit leveling. So, as we can not make the direct connections between coastal countries, due to the inability of the spirit leveling method to cross the water bodies, they are weak in these regions. In this study, we assessed the impact of using model-based hydrodynamic leveling connections among the North Sea countries on the quality at which the European Vertical Reference System can be realized. In doing so, we combined the model-based hydrodynamic leveling data with synthetic geopotential differences among the height markers of the Unified European Leveling Network (UELN) used to realize the European Vertical Reference Frame 2019. The uncertainties of the latter data set were provided by the BKG. The impact is assessed in terms of both precision and reliability. We will show that adding model-based hydrodynamic leveling connections lowers the standard deviations of the estimated heights in the North Sea countries significantly. In terms of reliability, no significant improvements are observed.</p>

scholarly journals Assessment of tidal range changes in the North Sea from 1958 to 2014

2021 ◽  
Author(s):  
Leon Jänicke ◽  
Andra Ebener ◽  
Sönke Dangendorf ◽  
Arne Arns ◽  
Michael Schindelegger ◽  
...  
Keyword(s):  
North Sea ◽  
German Bight ◽  
Large Scale ◽  
Tide Gauge ◽  
Tidal Range ◽  
Tide Gauges ◽  
Tide Gauge Records ◽  
Large Spatial Scale ◽  
The North ◽  
The North Sea

<p>Tide gauges throughout the North Sea basin show significant changes in the local tidal regime since the mid-20th century, especially in the German Bight area. These changes were analyzed within the DFG-funded project TIDEDYN (Analyzing long term changes in the tidal dynamics of the North Sea, project number 290112166) and the final results were recently published in Jänicke et al. (2020, https://doi.org/10.1029/2020JC016456).</p><p>In this paper, we document an exceptional large-spatial scale case of changes in tidal range in the North Sea, featuring pronounced trends between -2.3 mm/yr at tide gauges in the UK and up to 7 mm/yr in the German Bight between 1958 and 2014. These changes are spatially heterogeneous and driven by a superposition of local and large-scale processes within the basin. We use principal component analysis to separate large-scale signals appearing coherently over multiple stations from rather localized changes. We identify two leading principal components (PCs) that explain about 69% of tidal range changes in the entire North Sea including the divergent trend pattern along UK and German coastlines that reflects movement of the region’s semidiurnal amphidromic areas. By applying numerical and statistical analyses, we can assign a baroclinic (PC1) and a barotropic large-scale signal (PC2), explaining a large part of the overall variance. A comparison between PC2 and tide gauge records along the European Atlantic coast, Iceland and Canada shows significant correlations on time scales of less than 2 years, which points to an external and basin-wide forcing mechanism. By contrast, PC1 dominates in the southern North Sea and originates, at least in part, from stratification changes in nearby shallow waters. In particular, from an analysis of observed density profiles, we suggest that an increased strength and duration of the summer pycnocline has stabilized the water column against turbulent dissipation and allowed for higher tidal elevations at the coast.</p><p>We would like to present these research results and the content of the paper (cf. Jänicke et al., 2020) at vEGU21, hoping to encourage subsequent questions and further discussions.</p>

Partial validation of a numerical model for tidal motion in the Tay Estuary

1987 ◽  
Vol 92 (3-4) ◽  
pp. 275-283
Author(s):  
D. J. Gunn ◽  
J. McManus ◽  
O. Yenigun
Keyword(s):  
Mathematical Model ◽  
Numerical Model ◽  
Boundary Conditions ◽  
North Sea ◽  
Integral Method ◽  
The Road ◽  
Tidal Motion ◽  
The North ◽  
Open Sea ◽  
The North Sea

SynopsisIn a mathematical model of the Tay (Gunn & Yenigun 1987) based upon the Local Integral Method (Gunn & Yenigun 1985), tidal levels at the seaward boundaries and velocities at landward boundaries are used in setting boundary conditions, so that validation studies are mainly based upon changes in internal tidal levels, and comparison between computed and measured velocities within the modelled region. The comparisons of tidal levels within this estuary over a 5.0 m tide showed agreement with overall values from Buddon Ness to the rail bridge, but within the overall agreement there were significant differences in the immediate vicinity of the road bridge. Velocities predicted within the estuary have been compared with measurements provided by a number of surveys in the period from 1972-78. The agreement between experiment and prediction was good in the central and western regions of the model, but the comparison between measurement and prediction was less good near the eastern boundaries. The principal reason for poorer agreement in the east was the difficulty in setting boundary conditions at the open sea extremes of the model. The most satisfactory way of improving the model near the open sea boundaries would be to link the model for the Tay with a model for velocity and level in the North Sea.

scholarly journals ROMS Based Hydrodynamic Modelling Focusing on the Belgian Part of the Southern North Sea

2021 ◽  
Vol 9 (1) ◽  
pp. 58
Author(s):  
Georgios Klonaris ◽  
Frans Van Eeden ◽  
Jeffrey Verbeurgt ◽  
Peter Troch ◽  
Denis Constales ◽  
...  
Keyword(s):  
Numerical Model ◽  
North Sea ◽  
Three Dimensional ◽  
Water Levels ◽  
Ocean Modeling ◽  
Added Value ◽  
Wind Fields ◽  
Regional Ocean Modeling System ◽  
The North ◽  
The North Sea

The North Sea is a shallow sea that forms a complex physical system. The nonlinear interaction of the astronomical tides, varying wind fields and varying pressure systems requires appropriate approaches to be described accurately. An application based on the advanced numerical model Regional Ocean Modeling System (ROMS) was newly developed by the authors, tailored to simulate these hydrodynamic processes in the North Sea and the Belgian Continental Shelf, which is the area of particular interest in the present study. The purpose of this work is to develop and validate a state-of-the-art three-dimensional numerical model to form the basis of a compound operational and forecasting tool for the Belgian coastal zone. The model was validated with respect to water levels and temperature. Validation for astronomical tides was accomplished through the comparison of the principal constituents between the model results and observations at a number of tidal gauges in Belgium and other countries. A statistical analysis of the results showed that the model behaves as expected throughout the North Sea. The model response to the varying meteorological conditions was also validated using hindcast data for 2011 as input. In this case, the comparison between observed and modelled water levels showed a good agreement with average RMSE in Belgium 9.5 cm. Overall, the added value of this work is the development of an independent model for validation and comparison with other models and which can be used as an efficient tool for operational and forecasting purposes.

The North Sea pole tide described through a tide-surge numerical model

1994 ◽  
Vol 21 (6) ◽  
pp. 449-452 ◽  
Author(s):  
M. N. Tsimplis ◽  
R. A. Flather ◽  
J. M. Vassie
Keyword(s):  
Numerical Model ◽  
North Sea ◽  
Pole Tide ◽  
The North ◽  
The North Sea
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