Geoscience Reference
In-Depth Information
In Figure 2.17, what can be found is the deepening of the thermocline
at mid-latitudes and its presence close to the surface near the Equator,
which makes the Equator very reactive to disturbances since the cold
waters easily come to the surface. In the tropics, ocean and atmosphere
are coupled and interact easily. Deeper regions do not have a direct link
with the atmosphere and their water masses are renewed by advection
from the surface through ventilation/subduction for the thermocline
waters, and by convection for deep waters, then by diffusion and
mixing with surrounding waters.
2.3.8.
Schematization of global circulation: the great conveyor belt
General oceanic circulation results from the main mechanisms that
we have just discussed: the formation of water masses at the surface
by exchange with the atmosphere, injection into the depths by
convection at high latitudes or subduction at subpolar/mid-latitudes,
ascent of water through coastal and tropical
upwellings
, anticyclonic
circulation in large mid-latitude basins and cyclonic circulation in
polar regions, these thermal and dynamical phenomena being much
more efficient at redistributing water masses and their properties than
simple diffusion. The resulting image is complex because the
geographical configurations of each ocean are different and each one of
them develops a circulation unique to itself.
OCEAN - ATMOSPHERE
INTERACTIONS
CONVECTION
VENTILATION
THERMOCLINE
INTERMEDIATE WATERS
DEEP WATER
Figure 2.17.
Temperature profile of the global ocean, as a zonal average
