scholarly journals Numerical modelling of physical processes governing larval transport in the Southern North Sea

2013 ◽  
Vol 10 (5) ◽  
pp. 1765-1806 ◽  
Author(s):  
M. C. H. Tiessen ◽  
L. Fernard ◽  
T. Gerkema ◽  
J. van der Molen ◽  
P. Ruardij ◽  
...  
Keyword(s):  
North Sea ◽  
Sea Water ◽  
A Priori ◽  
Three Dimensional ◽  
Larval Transport ◽  
Absolute Amount ◽  
Annual Variability ◽  
The North ◽  
The North Sea ◽  
Selection Of

Abstract. A three-dimensional hydrodynamic model (GETM) was coupled with a particle tracking routine (GITM) to study the inter-annual variability in transport paths of particles in the North Sea and English Channel. For validation, a comparison with observed drifter trajectories was made. The aim was to investigate to what extent variability in the hydrodynamic conditions alone (reflecting passive particle transport) contributed to inter-annual variability in transport of eggs and larvae. In this idealized study, no a-priori selection of spawning grounds or periods was made and no active behaviour (vertical migration) or mortality were included. Egg and larval development towards coastal nursery areas was based solely on sea water temperature, while settlement areas were defined by a threshold water depth. Results showed strong inter-annual variability in drift direction and distance, caused by a combination of wind speed and direction. Strong inter-annual variability was observed both in absolute amount of settlement in coastal areas, as well as in the relative importance of the different areas. Settlement in the western Dutch Wadden Sea not only showed inter-annual variability, but patterns were also variable within each year and revealed seasonal changes in the origin of particles.

scholarly journals Numerical modelling of physical processes governing larval transport in the southern North Sea

Ocean Science ◽  
2014 ◽  
Vol 10 (3) ◽  
pp. 357-376 ◽  
Author(s):  
M. C. H. Tiessen ◽  
L. Fernard ◽  
T. Gerkema ◽  
J. van der Molen ◽  
P. Ruardij ◽  
...  
Keyword(s):  
North Sea ◽  
Sea Water ◽  
A Priori ◽  
Three Dimensional ◽  
Larval Transport ◽  
Absolute Amount ◽  
English Channel ◽  
Annual Variability ◽  
The North ◽  
The North Sea

Abstract. A three-dimensional hydrodynamic model (GETM) was coupled with a particle tracking routine (GITM) to study the inter-annual variability in transport paths of particles in the North Sea and English Channel. For validation, a comparison with observed drifter trajectories is also presented here. This research investigated to what extent variability in the hydrodynamic conditions alone (reflecting passive particle transport) contributed to inter-annual variability in the transport of eggs and larvae. In this idealised study, no a priori selection of specific spawning grounds or periods was made and no active behaviour (vertical migration) or mortality was included. In this study, egg and larval development towards coastal nursery areas was based solely on sea water temperature, while settlement areas were defined by a threshold water depth. Results showed strong inter-annual variability in drift direction and distance, caused by a combination of wind speed and direction. Strong inter-annual variability was observed both in absolute amount of settlement in several coastal areas, and in the relative importance of the different areas. The effects of wind and temperature variability are minor for settlement along the western shores of the North Sea and in the English Channel, but have a very significant impact on settlement along the eastern shores of the North Sea. Years with strong south-westerly winds across the Dover Straight resulted in higher settlement figures along its eastern shores of the North Sea (standard deviation 37% of the mean annual settlement value). Settlement in the western Dutch Wadden Sea did not only show inter-annual variability, but patterns were also variable within each year and revealed seasonal changes in the origin of particles: during winter, stronger currents along with colder temperatures generally result in particles originating from further away.

Sandeel (Ammodytes marinus) larval transport patterns in the North Sea from an individual-based hydrodynamic egg and larval model

2008 ◽  
Vol 65 (7) ◽  
pp. 1498-1511 ◽  
Author(s):  
Asbjørn Christensen ◽  
Henrik Jensen ◽  
Henrik Mosegaard ◽  
Mike St. John ◽  
Corinna Schrum
Keyword(s):  
Time Series ◽  
North Sea ◽  
Larval Growth ◽  
Three Dimensional ◽  
Larval Transport ◽  
Sea Transport ◽  
The North ◽  
Modelling Framework ◽  
The North Sea ◽  
Transport Patterns

We have calculated a time series of larval transport indices for the central and southern North Sea covering 1970–2004, using a combined three-dimensional hydrodynamic and individual-based modelling framework for studying sandeel ( Ammodytes marinus ) eggs, larval transport, and growth. The egg phase is modelled by a stochastic, nonlinear degree-day model describing the extended hatch period. The larval growth model is parameterized by individually back-tracking the local physical environment of larval survivors from their catch location and catch time. Using a detailed map of sandeel habitats in the North Sea, the importance of hydrography for early life stages of sandeel to their recruitment success is explored. We find that the sandeel larval transport patterns in the North Sea are relatively robust toward uncertainties in biological parameters, when mortality aspects are included. We find only weak spatiotemporal correlations between elements of the transport indices in the time series, mainly positive correlation between retention terms for the same year. The transport connectivity of sandeel habitats in the North Sea and the dynamical properties of the North Sea transport system are also analyzed, and we introduce novel a scheme to quantify direct and indirect connectivity on equal footings in terms of an interbank transit time scale.

scholarly journals Predictive framework for codend size selection of brown shrimp (Crangon crangon) in the North Sea beam-trawl fishery

PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0200464 ◽  
Author(s):  
Juan Santos ◽  
Bent Herrmann ◽  
Daniel Stepputtis ◽  
Claudia Günther ◽  
Bente Limmer ◽  
...  
Keyword(s):  
North Sea ◽  
Brown Shrimp ◽  
Beam Trawl ◽  
Crangon Crangon ◽  
Size Selection ◽  
Trawl Fishery ◽  
The North ◽  
Sea Beam ◽  
The North Sea ◽  
Selection Of

scholarly journals An ensemble study of extreme storm surge related water levels in the North Sea in a changing climate

Ocean Science ◽  
2009 ◽  
Vol 5 (3) ◽  
pp. 369-378 ◽  
Author(s):  
A. Sterl ◽  
H. van den Brink ◽  
H. de Vries ◽  
R. Haarsma ◽  
E. van Meijgaard
Keyword(s):  
North Sea ◽  
Climate Model ◽  
Sea Water ◽  
Global Climate ◽  
Global Climate Model ◽  
Storm Surges ◽  
Water Levels ◽  
The North ◽  
Extreme Storm ◽  
The North Sea

Abstract. The height of storm surges is extremely important for a low-lying country like The Netherlands. By law, part of the coastal defence system has to withstand a water level that on average occurs only once every 10 000 years. The question then arises whether and how climate change affects the heights of extreme storm surges. Published research points to only small changes. However, due to the limited amount of data available results are usually limited to relatively frequent extremes like the annual 99%-ile. We here report on results from a 17-member ensemble of North Sea water levels spaning the period 1950–2100. It was created by forcing a surge model of the North Sea with meteorological output from a state-of-the-art global climate model which has been driven by greenhouse gas emissions following the SRES A1b scenario. The large ensemble size enables us to calculate 10 000 year return water levels with a low statistical uncertainty. In the one model used in this study, we find no statistically significant change in the 10 000 year return values of surge heights along the Dutch during the 21st century. Also a higher sea level resulting from global warming does not impact the height of the storm surges. As a side effect of our simulations we also obtain results on the interplay between surge and tide.

Pollution of the Outer Oslofjord

1991 ◽  
Vol 24 (10) ◽  
pp. 321-322
Author(s):  
Kjell Baalsrud
Keyword(s):  
North Sea ◽  
General Circulation ◽  
Sea Water ◽  
Sewage Treatment ◽  
Circulation Pattern ◽  
Polluted Water ◽  
The North ◽  
Recreation Area ◽  
The North Sea ◽  
Sill Depth

The Outer Oslofjord has recently been subject to concern. 1. The Inner Oslofjord. Covers an area of 193 km2, is 160 m deep and is separated from the Outer Oslofjord by the narrow Drøbak sound with a sill depth of less than 20 metres. This part of the Oslofjord constitutes an enclosed body of sea water, sensitive to pollution, receiving sewage from approximately 650,000 inhabitants. In spite of modern sewage treatment, the fjord still suffers torn eutrophication problems resulting in reduced oxygen in the deep water, and areas of anoxic bottom water. The fjord is an important recreation area. 2. The Outer Oslofjord. Recent findings indicate that eutrophication is slowly increasing. An increasing eutrophication of the Outer Oslofjord wil also increase the need (and cost) of better sewage treatment in the Inner Oslofjord. 3. The North Sea. The quality of the water in the Oslofjord area is also dependent on the water it receives from the Skagerrak. The Skagerrak water will periodically receive polluted water from the southern North Sea and Kattegat. When these episodes coincide with water renewals between the Oslofjord and the Skagerrak, the fjord will receive polluted water from other countries. The Oslofjord water will in turn discharge into the Skagerrak, but due to the general circulation pattern, this will mainly influence the Norwegian south-east coast.

Selection of Scale Control Strategy on a Sub Sea Developed Field in the North Sea and How 6 Different Companies Contributed

2014 ◽  
Author(s):  
E. Sørhaug ◽  
M.M. Jordan ◽  
R.A. McCartney ◽  
R. Stalker ◽  
E.J. Mackay ◽  
...  
Keyword(s):  
North Sea ◽  
Control Strategy ◽  
The North ◽  
The North Sea ◽  
Scale Control ◽  
Selection Of
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