Geoscience Reference
In-Depth Information
The southward mass transport in the North Atlantic Ocean, due to a
wind, is in the order of 30 million m
3
/s or 30 Sv (1 Sv or Sverdrup =
1 million m
3
/s). As for the Gulf Stream, it does not transport 30 Sv
northward but nearly 100 Sv. Its power is such that it has a self-
pulling effect and creates a strong recirculation of the water masses,
which increases its amplitude, with complex phenomena of nonlinear
turbulent interactions. This phenomenon of amplified western boundary
currents, rendered possible by the conservation of the total vorticity,
which is also called the “
characterizes the variation
of the planetary vorticity according to the latitude, is present in the
circulation of all basins, whether that is for surface currents or for
bottom currents.
β
effect” where
β
We have described here the instance of the intensification of
western boundary currents in anticyclonic circulation at mid-latitudes;
the same phenomenon is acting to produce western boundary currents
in subpolar cyclonic circulations, or in deep circulation.
Strong
planetary
vorticity
East
Coast
West
Coast
Negative
vorticity
transmitted
by wind
Weak
planetary
vorticity
Figure 2.13.
Diagram illustrating the Sverdrup circulation and
the western boundary current
