The Ocean and the Climate System - Ocean in the Earth System - page 86

Figure 2.18. Schematic representation of the general oceanic circulation conveyor
belt (from [BRO 79], modified by E. Maier Raimer, AV/D3/99-2 (CLIVAR))
A scheme allowing the general circulation to be illustrated has been
suggested and popularized by Broecker [BRO 79] and remains
attractive for understanding the global behavior of the ocean and the
scales involved (Figure 2.18). It is effectively a conveyor belt , which
enables the arrival of North Atlantic Deep Waters in the global ocean
to be followed. We explain its main traits here:
- the North Atlantic Deep Waters leave the subpolar regions of the
North Atlantic following the western boundary between 2,000 and
4,000 m; they are joined in the North Atlantic by Mediterranean Deep
Waters;
- they cross the Equator and enter the Southern hemisphere,
always on the western boundary which they only leave to be pulled
into the Antarctic Circumpolar Current;
-around the Antarctic, they are intensely mixed and return
progressively north in the thermocline waters in the Pacific, Atlantic
and Indian basins;