A three-dimensional model of circulation in a frontal region of the North Sea

1989 ◽  
Vol 42 (3-6) ◽  
pp. 231-247 ◽  
Author(s):  
Ian D. James
Keyword(s):  
North Sea ◽  
Three Dimensional ◽  
Frontal Region ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
The North ◽  
The North Sea

scholarly journals ROLE OF 2D AND 3D MODELS IN JONSDAP '76

1978 ◽  
Vol 1 (16) ◽  
pp. 63
Author(s):  
A.M. Davies
Keyword(s):  
North Sea ◽  
Three Dimensional ◽  
3D Models ◽  
Three Dimensional Model ◽  
North West ◽  
The North ◽  
Dimensional Distribution ◽  
The North Sea ◽  
2D And 3D

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.

Eclectic modelling of the North Atlantic. II. Transient tracers and the ventilation of the Eastern Basin thermocline

1988 ◽  
Vol 325 (1583) ◽  
pp. 201-236 ◽  
Keyword(s):  
North Atlantic ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Ekman Pumping ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Oxygen Utilization ◽  
The North ◽  
Time Histories ◽  
Weak Constraints

Renewal rates of the waters of the thermocline in the eastern North Atlantic are estimated by combining linear quasi-geostrophic dynamics with steady and transient tracers into a unified eclectic, reservoir model. The two-dimensional model first employed is finally rejected when it is found that it generates oxygen-utilization rates (OUR) that are, by conventional biological wisdom, too high. The three-dimensional model that replaces the two-dimensional one shows that the our is indeterminate, with possible ranges from zero to unacceptably high values. The region is flushed primarily from the north and east. The problem of using transient tracers is mathematically equivalent to that of distributed-system boundary-control theory, the open-ocean boundary conditions playing the role of the unknown control variables. The missing time histories of this new set of unknowns means that tritium and helium-3 distributions are only comparatively weak constraints on the flow field, but do set upper bounds on the vertical exchange with surface waters. Surface Ekman pumping is adequate to explain the interior distributions without additional buoyancy ventilation, although this latter process is possible. Some speculation is made about conditions under which transient tracers might play a more definitive role.

A three-dimensional gravity model of the southern contact of the Sebago pluton, Maine

1998 ◽  
Vol 35 (6) ◽  
pp. 649-656 ◽  
Author(s):  
Mark D Behn ◽  
J Dykstra Eusden, Jr. ◽  
John A Notte III
Keyword(s):  
Three Dimensional ◽  
Average Thickness ◽  
Uniform Thickness ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Metasedimentary Rocks ◽  
The North ◽  
Dimensional Gravity ◽  
Relationship Of ◽  
The Relationship

The Sebago pluton is a two-mica granite that intruded the metasedimentary rocks of the Central Maine Terrane around 292 Ma. In recent years, geologists have raised an increasing number of questions related to the overall thickness of the Sebago pluton and the position of its subsurface contact with the underlying metasedimentary rocks. Past studies have shown the Sebago pluton to be a thin, 1-2 km thick, subhorizontal sheet dipping 3° to the northeast. This study examines anomalies in the Earth's gravitational field related to the southern portion of the Sebago pluton, specifically to determine the thickness of the pluton and to locate the subsurface contact between the pluton and the underlying metasedimentary rocks. A three-dimensional model shows the thickest portions of the pluton (~1.8 km) to occur at the bottom of a bowl hape along the southwestern contact. Moreover, the model shows the pluton to thin toward the northern and eastern regions of the study area, where the average thickness is less than 0.5 km. The pluton appears to extend southward below the cover of the metasedimentary rocks along the southwestern contact. Thus, contrary to previous models, the Sebago pluton is not a northeasterly dipping sheet of uniform thickness, but rather an arched sheet with an irregular thickness extending beneath the metasedimentary rocks along both its northern and southern contacts. Based on this new geometry, either the relationship of the pluton to the surrounding metamorphic zones must be modified, or the possibility must be considered that the Sebago pluton is actually a composite batholith, composed of a younger (Permian) granite to the north and an older (Carboniferous) granite to the south.

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