Introductory Oceanography (OCNG 251) MidTerm Study Guide: Part 2

Deep water formation thus occurs in high latitude regions as presented in Figure 38.
Figure 38. Source of deep‐water formation in dark green with water mass direction of flow.
7) Global ocean circulation
The global ocean circulation is thus a link between surface water loops and deep‐water mass
movements. The overall “conveyor belt” circulation takes a few hundred years (~500 years) but
is not static over time; circulation can accelerate or decelerate depending on climate conditions
and/or water balances. For example the large addition of freshwater to the surface North
Atlantic could decrease the densification of surface water in the North Atlantic and thus slow
down the entire deep‐water circulation, which itself could also alter the speed of surface
returning currents. Hence, the global ocean circulation links all oceans to each other and depends
on atmospheric circulation and wind patterns. The entire structure of earth (sphericity,
seasonality, fluid envelopes in the atmosphere and ocean, rotation of the earth, presence of
continents) affect the redistribution of heat from its zones of surplus (inter‐tropical zones) to its
zones of deficits (high latitudes).