What is the thermohaline circulation of the World Ocean?

The total area of the World Ocean - the water envelope of the Earth - 361.1 million km ². This is a unified system that has its biological, chemical and physical characteristics, due to the change in which the ocean "lives" in one direction or another, changes and circulates.

The world ocean is water, therefore all its physical and chemical features depend on the change of this environment.

The causes of water circulation in the ocean

Water is a moving environment and in nature it is always in constant motion. The circulation of water in the ocean occurs for several reasons:

1. The circulation of the atmosphere is wind.
2. The movement of the earth around its axis.
3. Impact of the force of gravity of the Moon and the Sun.

The main reason for the movement of water is the wind. It affects the water masses of the World Ocean, causes surface currents, and they, in turn, carry this mass to different parts of the ocean. Because of internal friction, the energy of translational motion is transferred to the underlying layers, and they also begin to move.

The wind affects only the surface layer of water - up to 300 meters from the surface. And if the upper layers move fast enough, the lower layers move slowly and depend on the bottom relief.

If we consider the World Ocean as a single whole, then according to the flow pattern one can see that they represent two large whirlpools, which are divided by an equator. In the Northern Hemisphere, water moves clockwise, in the Southern - against. At the borders of continents, currents can deviate in their motion. Also, the flow velocity near the western shores is higher than near the eastern ones.

The currents do not move in a straight line, but deviate in a certain direction: in the Northern Hemisphere - to the right, and in the Southern - in the opposite direction. This is due to the Coriolis force, which arises as a result of the rotation of the Earth around its axis.

Water in the ocean can rise and fall. This is due to the attraction of the Moon and the Sun, because of which there are tides. Their intensity changes over a period of time.

Thermohaline circulation of the World Ocean

"Halina" is translated as "salinity". Together, the salinity and temperature of the water determine its density. Water in the World Ocean circulates, currents carry warm water from equatorial latitudes into polar waters - so warm water is mixed with cold water. In turn, cold currents transfer water from polar latitudes to equatorial ones. This process is continuous.

Thermohaline circulation proceeds at depth, in the lower layer of currents. As a result of this process convective movements of water occur - cold, heavier water descends and moves towards the tropics. Thus, the surface currents move in one direction, and the deep currents move in the other direction. This is how the global ocean circulates.

Thermohaline currents

Surface currents of the World Ocean accumulate heat at the equator, and when moving to high latitudes gradually cool. At low latitudes, as a result of evaporation, water increases its specific gravity, its salinity increases. Reaching polar latitudes, water descends, deep currents are formed.

There are several large currents, for example the Gulf Stream (warm), the Brazilian (warm), the Canary (cold), the Labrador (cold) and others. Thermohaline circulation occurs according to the same scheme for all currents: both warm and cold.

Gulf Stream

One of the largest warm currents of the planet is the Gulf Stream. It has a huge impact on the climate of northern and western Europe. The Gulf Stream flows its warm waters to the shores of the continent, thus defining the relatively mild climate of Europe. Then the water cools and falls, and a deep stream carries it to the equator.

The famous ice-free port of Murmansk is such due to the Gulf Stream. If we consider the fiftieth latitudes of the Northern Hemisphere, it can be seen that in the western part (in Canada) at a given latitude is a severe climate, the tundra zone passes, and in the Eastern Hemisphere, deciduous forests grow at a similar latitude. Along with the warmest current, it is even possible to grow palms, the climate is so warm here.

The dynamics of the circulation of this current changes throughout the year, but the influence of the Gulf Stream is always great.

Influence on the Earth's climate

In the regions of the Weddell and Norwegian seas, water of increased salinity comes from equatorial latitudes. In high latitudes, it cools to freezing point. When ice is formed, the salt does not enter into it, so that the underlying layers become more salty and dense. Such water is called the North Atlantic deep or Antarctic bottom.

Thermohaline circulation of the World Ocean passes through a closed system.

Thus, we came to the conclusion that the greater the depth, the higher the density of water. In the ocean, lines of constant density run almost horizontally. Water with different physical and chemical properties is much easier to mix along a constant density line than against it.

Thermohaline circulation has not been studied well enough. It is known that this process affects not only the state of the waters of the World Ocean, but also indirectly affects the Earth's climate. All systems on our planet are closed, so changing one subunit leads to a change in the others.