¶ … motion of water. In the Ocean there are three major types of currents; Tidal, Coastal, and Surface Ocean.
Coastal currents are movements of water that are located near the coast and are influenced by wind, waves and land formations. Surface Ocean currents are currents that are located throughout the oceans, involve much more complex influences like global wind systems, the spin of the earth, salinity, and water temperatures.
Normally wind patterns on the earth follow a cycle of circulation between the equator and the poles. But because the earth rotates on it's axis, these normally north and south wind patterns develop a slight curve, called the Coriolis effect. In the northern hemisphere this effect causes the winds to curve to the right, in the southern hemisphere, to the left. As the winds blow on the surface of the oceans, it drags the surface of the water in the same direction as the winds. This causes the major surface currents to follow flow in a circular pattern, clockwise in the northern hemisphere and counter clockwise in the southern.
D. The Coriolis effect creates a circular current...
The wind can cause surface currents, but the mechanism behind the circular system is called the global conveyor belt. When warm water is dragged by wind currents to the polar regions, it becomes cold, and cold water sinks. As it sinks, it comes under the influence of other deep water currents which flow in the opposite direction, toward the equator. Currents at deeper levels flow in opposite directions because of the Ekman Spiral; an side effect of the Coriolis effect. The spin of the earth causes the flow of water either slightly to the right, or the left; but as one goes deeper into the ocean, this effect becomes greater and greater until the water is actually moving in the opposite direction.
E. Traditionally ocean current have been measured by the simplest of means; usually an observer and two stationary points. An object, called a "drifter," would be dropped into the water, and the time it took to travel from one point to the other was measured. The observer could then calculate the velocity of the current. While today's seafarers use the same…
