Abstract
Scaling of the equations of motion of the Antarctic Circumpolar Current indicates that the Rossby number and the Ekman number are 10-4to 10-5but the vertical Ekman number may reach unity in the bottom boundary layer. The equations of motion are integrated vertically from the surface to the bottom and averaged over a latitude circle. The resulting equation in the meridional direction is predominantly geostrophic, whereas the main terms of the equation in the zonal direction are the wind stress and the bottom stress. When the vertical eddy viscosity near the bottom is of the order of 102cm2, /sec, the total zonal transport through the Drake Passage computed from the balance of the wind stress and the bottom stress equals 260×106m3/sec, the amount determined by REID and NOWLIN (1970) from observations.
The northward transport reduces the eastward transport corresponding to the wind stress of the westerlies in the A. C. C. through the Coriolis' term in the vertically integrated equation of motionof the zonal direction. South of the Drake Passage, such reduction reaches about ten percent of the wind-driven transport mainly due to the peripheral water discharge. North of the Drake Passage, the northward transport may be generated by the effect of the South American coast which prevents free eastward movement of the A. C. C., causing a wake to the east.This transport may contribute to a part of the northward transport of the bottom water postulated by MUNK (1966). The effect of the horizontal eddy viscosity in the zonal transportequation is negligible except near the Antarctic coast, if the eddy viscosity is less than109cm2/sec.
