scholarly journals Assessment of three-dimensional physical-biological ECOHAM1 simulations by quantified validation for the North Sea with ICES and ERSEM data

2000 ◽  
Vol 57 (4) ◽  
pp. 1060-1068 ◽  
Author(s):  
A Moll
Author(s):  
Juan A. Ramírez-Macías ◽  
Rafael E. Vásquez ◽  
Asgeir J. Sørensen ◽  
Svein Sævik

Dynamic Positioning (DP) capability studies are used to assess if a vessel has sufficient thrust capacity to withstand environmental loads while keeping its position and orientation at a specified set-point or path. These studies are usually performed on ships and other DP-controlled surface vessels; consequently, standards and procedures for these are widely known. In this work, a methodology for conducting a DP capability study for Remotely Operated Vehicles (ROV) is presented. Due to the nature of ROV operations, a DP capability study should include different features that are not common to surface vessels. In this case, an ROV connected to a surface vessel through a tether is considered. During operation, the tether is subject to varying current loads that are accumulated along the water column and transferred to the vehicle. Therefore, the ROVs thrusters must be able to withstand, in addition to its own drag, three-dimensional loads due to three-dimensional currents and umbilical-related loads. To illustrate the methodology, two case studies are considered: the DP capability of an ROV that has to operate in the Colombian Caribbean and an existing ROV operating in the 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 ◽  
...  

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.


1978 ◽  
Vol 1 (16) ◽  
pp. 63
Author(s):  
A.M. Davies

This paper describes how a two-dimensional numerical model of the North Sea was used to determine optimum positions for the deployment of off-shore tide gauges during the JONSDAP '76 oceanographic exercise. A three-dimensional model of the North West European Shelf is also described. Using this model the three-dimensional distribution of the M2 tidal current over the shelf has been computed. This model has also been used to compute the wind induced circulation of the North Sea for the INOUT period of JONSDAP '76.


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