Oceanic or sea currents - horizontal movement of water masses. As a rule, their movement occurs in a strictly defined direction and can be of great length. The current map below shows them in full.
Water flows are of considerable size: they can reach tens or even hundreds of kilometers wide, and have a great depth (hundreds of meters). The speed of ocean and sea currents is different - on average, it is 1-3 thousand m / h. But, there are also so-called high-speed ones. Their speed can reach 9,000 m/h.
Where do currents come from?
The causes of water currents may be a sharp change in water temperature due to heating, or, conversely, cooling. They are also affected by different densities, for example, at a place where several flows (marine and oceanic) collide, precipitation, evaporation. But basically cold and warm currents arise due to the action ofwinds. Therefore, the direction of the largest oceanic water flows depends mainly on the air currents of the planet.
Currents driven by winds
An example of constantly blowing winds are the trade winds. They start their life from the 30th latitude. The currents that are created by these air masses are called trade winds. Allocate the southern trade wind and the northern trade wind current. In the temperate zone, such water flows are formed under the influence of westerly winds. They form one of the largest currents on the planet. There are two cycles of water flow in the northern and southern hemispheres: cyclonic and anticyclonic. Their formation is influenced by the inertial force of the Earth.
Varieties of currents
Mixed, neutral, cold and warm currents are varieties of circulating masses on the planet. When the water temperature of the stream is lower than the temperature of the surrounding water, it is a cold stream. If, on the contrary, it is its warm variety. Neutral currents do not differ from the temperature of the surrounding waters. And mixed ones can change over the entire length. It is worth noting that there is no constant temperature indicator of currents. This figure is very relative. It is determined by comparing the surrounding water masses.
In tropical latitudes, warm currents circulate along the eastern margins of the continents. Cold - along the western. In temperate latitudes, warm currents pass along the western shores, and cold ones along the eastern ones. The variety can also be determined by another factor. Yes, there are moreeasy rule: cold currents go towards the equator, and warm ones go away from it.
Meaning
It's worth talking about in more detail. Cold and warm currents play an important role on planet Earth. The significance of the water circulating masses is that due to their movement, the solar heat is redistributed on the planet. Warm currents increase the air temperature of nearby areas, and cold currents lower it. Formed on the water, water flows have a serious impact on the mainland. In areas where warm currents constantly pass, the climate is humid, where cold ones, on the contrary, are dry. Also, ocean currents contribute to the migration of the ichthyofauna of the oceans. Under their influence, plankton moves, and fish migrate after it.
You can give examples of warm and cold currents. Let's start with the first variety. The largest are such water flows: Gulf Stream, Norwegian, North Atlantic, North and South Tradewinds, Brazilian, Kurosio, Madagascar and others. The coldest currents of the oceans: Somali, Labrador, California.
Major currents
The largest warm current on the planet is the Gulf Stream. This is a meridional circulating flow that carries 75 million tons of water every second. The width of the Gulf Stream is from 70 to 90 km. Thanks to him, Europe gets a comfortable mild climate. From this it follows that the cold and warm currents largely affect the life of all living organisms on the planet.
Of the zonal, cold streams, the current is the most importantWestern winds. In the southern hemisphere, not far from the coast of Antarctica, there are no island or mainland clusters. A large area of the planet is completely filled with water. The Indian, Pacific and Atlantic oceans converge here in one stream, connecting into a separate huge body of water. Some scientists recognize its existence and call it Southern. It is here that the largest flow of water is formed - the course of the Western winds. Every second it carries a stream of water that is three times the size of the Gulf Stream.
Canarian current: warm or cold?
Currents can change their temperature. For example, the flow begins with cold masses. Then it warms up and becomes warm. One of the variants of such a circulating water mass is the Canary Current. It originates in the northeast of the Atlantic Ocean. It is directed by a cold stream along the Iberian Peninsula of Europe. Passing along the western coast of Africa, it becomes warm. This current has long been used by navigators to travel.
