110 



Nonlinear Theories — Inertial 



200 - 



\ 



100 - 



INTEGRATED 

 VORTICITY 



GEOSTROPHIC 

 ELOCITY 



50 



NAUT. MILES 



Fig. 65. Vorticity analysis of Worthington's section (19546; see figs. 33 and 

 34 of the present study). The vertical thickness of the 17-19° layer is indicated 

 in the upper graph. In the lower graph, the velocity computed by the vorticity 

 formula (7) is shown by the solid curve; the geostrophic velocity as computed 

 by Worthington, by the other curve. The fact that these two curves are fairly 

 similar suggests that the potential vorticitj' in the upper laj'ers of the Gulf 

 Stream is fairly uniform across the Stream. For the dynamical significance of 

 this, see the text. 



(Gulf Stream) in the upper layer just to the right of a: = 0, but, by hypothesis, 

 it must not extend very far into the central Atlantic (that is, v = for 

 large a;). Since the lower layer is regarded as being at rest everywhere, the 

 current velocity is given by the geostrophic relationship in terms oi D: 



dD 



fv-g' 



dx 



(8) 



