Water Bodies and Stationary Current Conditions at Boundary Surfaces 459 



equilibrium state, i.e. a uniform gradient current with the corresponding slopes of 

 the isobaric surfaces and of the sea level must be superimposed on the entire system 

 shown in Fig. 201. This will change somewhat the position of the isobaric surfaces and 

 that of the physical sea level. This circumstance should always be kept in mind in 

 dealing with the phenomena described in this section. 



The oceanic structure in the boundary area between the Labrador Current and the 

 Gulf Stream to the south of the Newfoundland Banks is usually chosen as an example 

 for the oceanic structure presented in Fig. 201. Figure 202 shows a section through the 



700 



800 



Fig. 202. Distribution of the specific volume anomalies in a meridional cross-section south 

 of the Great Banks of Newfoundland (according to Smith). Horizontal scale, 1:2 million; 



vertical scale, 1 : 5000. 



currents and the distribution of specific volume anomaly (Smith, 1926); the currents 

 here are approximately zonal ones (directed almost east-west). Disregarding the thin 

 top layer about 50 m thick, there is a heavier water body found in the middle flanked 

 to the north and south by water masses of greater specific volume. On the southern 

 side (Sts. 205 and 206) the lighter Gulf Stream water flows to the east (out of the plane 

 of the diagram), while on the northern side the water masses of the Labrador Current 

 flow towards the west in the area just to the south of the Newfoundland Banks 

 (Sts. 202 and 203). Figure 203 presents the topography, calculated from the mass 

 distribution, of some isobaric surfaces and of the physical sea level. As required by 

 theory, the presence of the heavier water body in the middle is shown by a low pressure 

 trough and at the surface by an elongated depression of the water level. 



(b) Motionless Light Water Body Embedded into Moving Heavier Water Masses 



The oceanic structure is also given here in the same way as for case (a) by the rules 

 for the stationary stratification of adjacent water bodies (Fig. 204). Here also the sea 

 level is lowest over the lighter water body, but this deep pressure trough diminishes 



