Major Ocean Surface Current Patterns
Mariners have known about the ocean currents that always move along certain paths since a long time ago. Then, they used them as helpers for transportation of goods. In 1772, for instance, the Gulf Stream Current was mapped by Benjamin Frankilin, although people knew very little about its nature. Today, with significant level of scientific development, we can easily see and analyze them.
Currents are conditioned by two forces – the sun and rotation of the Earth. The first can influence ocean in two different ways: creation of winds and altering the water density. Winds greatly affect upper layers of water, but beyond about 100 meters they don’t have any significant effect. The sun alters water density by changing its temperature and salinity. In this way density-dependent currents are created. Rotation of the Earth influences currents through the Coriolis force. Owing to it, the water in the currents flows to the left in the Southern Hemisphere and to the right in the Northern Hemisphere.
Surface currents flow in a regular pattern, but they are all different from one another. Some of them are deep and narrow, others are wide and shallow. They transport heat around the ocean, influencing climate in this way. Currents are important for the marine world, as they are known to move creatures around the world.
The currents create gyres. They help to transport heat away from equator. Still, there are places where gyres are not formed, for instance, near equator or in the Southern Ocean, where continuous westerly winds are prevailing. In this ocean the largest continuous circumglobal current is formed, where water is mixing between different ocean basins.