Ocean Currents

2 Parts to the Ocean Surface Deep Water

Surface Layer Layer at the top of the ocean Well mixed by waves, tides, and weather events like rain or a hurricane Sits on top of the deep water because the surface layer is less dense. Depth varies depending on location and season, but the depth is usually a couple hundred meters.

Thermocline Boundary layer between the surface layer and the deep waters Thermocline –Δ in T Causes change in density

Water Movement - Currents Move ocean water horizontally at the ocean's surface. Driven mainly by the wind (moving air) The Coriolis Effect –The Earth's spin causes the wind to curve. The wind in the northern hemisphere curves to the right and the wind in the southern hemisphere curves to the left.

Water Movement - Currents Location of land masses This movement of water helps spread energy from the Sun.

Deep Water T = about 3 degrees Celsius So, The biggest source of deep water is surface water that sinks in the North Atlantic Ocean. –Ocean water is very cold and very salty. –This cold, salty water is dense enough to sink into the depths of the ocean. Remember, the saltier and colder water is, the more dense it is! And more dense material will sink below less dense material!

Deep Water sinks slowly downward until it reaches a level of equal densityDense ocean surface water in the North Atlantic sinks slowly downward until it reaches a level of equal density. –If the water is more dense (colder and/or saltier) then any other water in the deep ocean, it will sink all the way to the sea floor.

Deep Water Once the water reaches a level of equal density, the water spreads out. –The deep ocean is broken into horizontal layers, with each deeper layer having more dense water in it.

Deep Water The water that sinks in the North Atlantic flows all the way past the equator into the Southern Hemisphere. The water then flows past Antarctica and into the Pacific and Indian Oceans. Some of the deep waters are warmed and so rise again to the surface.

Deep Water The cycle of ocean water circulation from the surface to the depths of the ocean back to the surface again is referred to as conveyor belt cycling.