total area of the oceans - water shell of the Earth - 361 100 000 km².It is a single system, which has its biological, chemical and physical features, due to the change which in this or that side of the ocean "live", is amended and circulated.
Oceans - is water, so all its physical and chemical characteristics depend on changes in the environment.
Causes of water circulation in the ocean
Water - is the fluid in nature, it is always in constant motion.The circulation of water in the ocean is happening for several reasons:
- atmospheric circulation - the wind.
- movement of the earth around its axis.
- impact of the force of attraction of the moon and the sun.
main cause of water movement is a breeze.It affects water mass oceans causes surface currents, and they, in turn, this mass is transferred to different parts of the ocean.Because of the internal friction energy of the translational motion is transmitted to the underlying layers, and they, too, begin to move.
Wind affects only the surface layer of water - up to 300 meters below the surface.And if the upper layers move fast enough, the lower move slowly and depend on bottom topography.
If we consider the world's oceans as a whole, the scheme flows can see that they are two large whirlpool, which are separated by the equator.In the Northern Hemisphere, the water moves clockwise in the Southern - against.At the borders of the continents flow may vary in their movement.Also, the rate of flow around the western shores of greater than about Oriental.
currents do not move in a straight line, and deflected in a certain direction: in the northern hemisphere - to the right and in the South - in the opposite direction.This is due to the Coriolis force, which arises as a result of rotation of the Earth about its axis.
water in the ocean can be raised and lowered.This is due to the attraction of the moon and the sun, because of which there are tides.Their intensity varies within a certain period of time.
thermohaline circulation of the oceans
«Halina" is translated as "salinity".Collectively, the water temperature and salinity determine its density.The water circulates in the oceans, currents carry warm water from the equator to the polar - so warm water mixed with cold.In turn, the currents carry cold water from the polar latitudes in the equatorial.This process occurs continuously.
thermohaline circulation takes place at a depth in the lower layer flows.As a result of this process occur convective movement of water - cold and heavier water sinks and moves toward the tropics.Thus, surface currents moving in one direction and depth - in another.So there is a general circulation of the oceans.
thermohaline currents
surface currents of the oceans accumulate heat at the equator, and when driving at high latitudes gradually cool down.At low latitudes evaporative water increases its share, its salinity increases.Arriving at polar latitudes, the water drops are formed deep currents.
There are several large currents such as the Gulf Stream (warm), Brazilian (warm), Canary (cold) Labrador (cold), and others.The thermohaline circulation is caused by one scheme for all movements: both heat and cold.
Gulfstream
One of the major warm currents of the planet - the Gulf Stream.It has a huge impact on the climate of northern and western Europe.Gulf Stream carries warm water to its shores of the continent, thus defines a relatively mild climate of Europe.Then the water cools and sinks, and the deep current carries it toward the equator.
famous ice-free port of Murmansk is such because of the Gulf Stream.If we consider the fifties latitude in the Northern Hemisphere, you can see that on the west side (in Canada) at a given latitude fairly harsh climate, it is a zone of tundra, in eastern hemisphere on the same latitude grow deciduous forests.Next to warm themselves over perhaps even growing trees, so a warm climate here.
circulation dynamics of flow varies during the year, but the influence of the Gulf Stream is always great.
Impact on the Earth's climate
in areas of the Weddell Sea and the Norwegian comes from equatorial latitudes increased water salinity.At high latitudes, it is cooled to the freezing point.When ice forms, the salt does not enter into it, so that the underlying layers become more salty and dense.This is called the North Atlantic Deep Water and the Antarctic bottom.
thermohaline circulation of the oceans takes place in a closed system.
Thus, we concluded that the greater the depth, the higher the density of water.In the ocean of constant density lines are almost horizontal.Water with different physico-chemical properties are much easier to stir for lines of constant density, than against it.
thermohaline circulation is not well studied.It is known that this process affects not only the state of the waters of the oceans, but also indirectly affects the Earth's climate.All systems on the planet closed, so a change of one subunit alters the other.
