Geoscience Reference
In-Depth Information
bordered to the North by the Indian Continent, transports heat to the
South.
The meridional heat transport in the ocean is produced by several
mechanisms. For example, the anticyclonic circulation in the
subtropics of the northern hemisphere carries along relatively cold
waters southward and pulls warm waters northward by western
boundary currents (wind-driven circulation). This results in a
northward heat transfer. Another way to ensure this transport is the
conveying of heat northwards by surface currents and drawing cold
waters toward the Equator deep in the ocean: there is therefore an
overturning loop that ensures this meridional transfer (thermohaline
circulation). In the North Pacific, it is the anticyclonic circulation that
ensures the poleward transport; in the North Atlantic, the two
phenomena overlap and contribute to the northward transport.
However, the typical timescales of these two phenomena are different:
the balance of the wind-driven circulation depends at mid-latitudes on
the propagation time of waves called Rossby Waves, which is in the
order of a few years to a decade, whereas the overturning cells set in
motion the transport of deep waters on a global scale, which occurs
over hundreds to thousands of years through the occurrence of
convection at high latitudes, which can be triggered very quickly.
Figure 2.19.
Estimations of heat transport in different regions of the ocean.
The transport is measured in Petawatts (which are 10
15
Watt)
