The Representation of Oceanic Movements and Kinematics 



361 



-Fig. 150. Chart of surface currents for August in the North Atlantic Ocean (according to 

 Schumacher). (Stereographic azimuthal projection accurate at the equator, scale at 0^ N., 

 30°W. 1: 108.) 



Velocity 

 3-0- 8-9 sm/Etm. 

 90-14-9 



15 0-20-9 



21 •0-29-9 



300-41 -9 



420-53-9 



540-65-9 



66-0-77-9 



( i knots) 

 ( 2 knots) 

 ( f knots) 

 (1 knots) 

 (U knots) 

 (2 knots) 

 (2i knots) 

 (3 knots) 



— < 

 — <- 



A- 





Steadiness 



Very steady 



Steady 



Rather steady 



Variable 

 rDead reckoning 

 J or taken from 

 1 other represent- 

 Lations 



Numerical limits for steadiness: from all ship displacements known in a certain area fall 

 inside the quadrant which is cut by the current direction into two halves (quadrant and 



octant, respectively) 



Very steady 

 Steady 



Rather steady 

 Variable 



quadrant (%) 

 (up to 45^ to the 

 right and left) 

 More than 67 

 More than 67 



33-66 

 More than 33 



octant (%) 



(at the most 22^° to 



the right and left) 



More than 67 



33-66 



33-66 



Less than 33 



Fig. 151. Singularities in the current field: (a) one-sided convergence, ib) one-sided diver- 

 gence, (c) and id) double-sided convergence and divergence ; for explanation see vertical 



cross-section. 



