92 



Linear Theories — Viscous 



force is a function of latitude. In low latitudes this function is nearly a 

 linear one: f=/3y, fi=lO~^^ J era. sec. The inequality in the absolute values 

 of the quantities A and B that occurs in this case immediately makes clear 

 the complete lack of east-west symmetry. The streamUnes dra\vn from this 

 formula are shown in fig. 58. The most striking feature of this figure is the 



Fig. 57. Contours of surface height in a uniformly rotating ocean (Stommel, 

 1948, fig. 4). 



Fig. 58. Streamlines for the case in which the Coriolis parameter is a linear 

 function of latitude (Stommel, 1948, fig. 5). 



intense crowding of streamlines toward the western border of the ocean. 

 The rest of the streamHne picture is broad and diffuse. The resemblance that 

 the velocity field of this simple case bears to that of the actual Gulf Stream 

 suggests that the westward concentration of streamlines in the wind-driven 

 oceanic circulation is a result of the variation of the Coriolis parameter 

 with latitude. 



