Holland, W. R., and A. D. Hirschman, 1972: A numerical calculation of the circulation in the North Atlantic Ocean. Journal of Physical Oceanography, 2, 336-354.
Abstract: A series of numerical experiments are carried out to simulate the three-dimensional
circulation in the North Atlantic Ocean and to examine the dynamics therein.
The calculations are partly diagnostic in that the density field is not
predicted but is given from observations. The main predicted quantities
are the velocity and pressure fields.
The results of the basic experiment are compared with observations. The
surface currents are quite similar to observations based upon ship draft
data, and the surface pressure field is nearly identical to the height of
the free surface constructed from a level-of-no-motion hypothesis. The deep
pressure variations are nowhere flat or level, however, and the predicted
deep currents are quite complex. They are, in fact, strongly controlled
by bottom topography and tend to follow f/H contours,where f is the Coriolis parameter and H the depth. The Gulf Stream transport is quite large, reaching a maximum
value of 81 x 106 m3 sec-1, despite the lack of important inertial effects in the western boundary
current. Subsidiary experiments show that this large transport value results
from an important interaction between the variable density field and bottom
topography in the western North Atlantic. When in one experiment the density
field was a homogenous one and in another the depth was constant, the maximum
transports in the western boundary current were only 14 and 28 x 106 m3 sec-1, respectively.
Other experiments show that the details of the wind-stress distribution
are unimportant when the density field is known; the density field contains
most of the information about the long term wind driving. For example, when
the wind stress is set equal to zero everywhere (but the density field is
maintained in its observed configuration), the Gulf Stream transport is
reduced by only 5%. Thus, the pressure torques associated with bottom topography
provide the main vorticity input. Finally, it is shown that the results
discussed in the basic experiment are not very sensitive to the details
of the density field used in the calculation. When these data are highly
smoothed and used in a subsidiary calculation, the important feartures,
such as enhanced tranpsort in the Gulf Stream and the topographic steering
of currents in the deep ocean, are unchanged.