ENVIRSC 1C03 Lecture 13: Module #13 Oceanic Circulation
Document Summary
There are several factors that drive the circulation of water in the ocean: temperature. Warm water is less dense than cold water and this difference in density induces the flow of water: salinity. Salty water is more dense than fresh water; salinity varies between latitudes: wind action on the surface. The ocean is made up of different thermal zones. At the surface is a warm layer that is mixed by waves and wind and is present at low and mid-latitudes. The thermocline is below the warm layer and is a zone of sharp decrease in temperature and therefore represents the density barrier. At the bottom is the cold deep water with temperatures near freezing; this zone has a much higher density than the mixed layer. Ocean currents are persistent and horizontal movements of ocean water. At the surface, they are driven by the friction from prevailing winds. This allows for the exchange of heat from low to high latitudes.