The World Ocean is one of the most mysterious phenomena. Even now it is not fully understood. Why is he unique? First of all, these are ocean currents. They play an important role in shaping the climate on planet Earth, and are also largely responsible for the diversity of flora and fauna. Today we will get acquainted with the types of currents, the reason for their occurrence, consider examples.
It's no secret that our planet is washed by four oceans: Pacific, Atlantic, Indian and Arctic. Naturally, the water in them cannot be stagnant, as this would have led to an ecological disaster long ago. Due to the fact that it constantly circulates, we can fully live on Earth. Below is a map of ocean currents, it clearly shows all the movements of water flows.
What is ocean current?
The current of the World Ocean is nothing but continuous or periodicmoving large masses of water. Looking ahead, we will immediately say that there are many of them. They differ in temperature, direction, depth passage and other criteria. Ocean currents are often compared to rivers. But the movement of river flows occurs only downward under the influence of gravitational forces. But the circulation of water in the ocean occurs due to many different reasons. For example, wind, uneven density of water masses, temperature difference, the influence of the Moon and the Sun, changes in pressure in the atmosphere.
Causes of occurrence
I would like to start my story with the reasons that give rise to the natural circulation of water. There is practically no exact information even at the present time. This is explained quite simply: the ocean system has no clear boundaries and is in constant motion. Now the currents that are closer to the surface have been studied in more depth. To date, one thing is known for sure, that the factors affecting the circulation of water can be both chemical and physical.
So, let's look at the main causes of ocean currents. The first thing I want to highlight is the effect of air masses, that is, wind. It is thanks to him that surface and shallow currents function. Of course, the wind has nothing to do with the circulation of water at great depths. The second factor is also important, it is the impact of outer space. In this case, the currents arise due to the rotation of the planet. And finally, the third main factor that explains the causes ofocean currents, - different density of water. All flows of the World Ocean differ in temperature, salinity and other indicators.
Directional factor
Depending on the direction, the ocean water circulation flows are divided into zonal and meridional. The first move to the west or to the east. Meridional currents go south and north.
There are also other species that are caused by the ebb and flow of the tides. Such ocean currents are called tidal. They have the greatest strength in shallow waters in the coastal zone, in the mouths of rivers.
Currents that do not change strength and direction are called stable, or settled. These include such as the North trade wind and the South trade wind. If the movement of the water flow changes from time to time, then it is called unstable, or unsettled. This group is represented by surface currents.
Surface currents
The most noticeable of all are the surface currents, which are formed due to the influence of the wind. Under the influence of the trade winds, constantly blowing in the tropics, huge streams of water are formed in the equator region. It is they who form the North and South equatorial (trade wind) currents. A small part of these water masses turns back and forms a countercurrent. The main streams are deflected north or south when they collide with the continents.
Warm and cold currents
Types of ocean currents play a crucial role in the distribution of climatic zones on Earth. Streams are called warm.water areas that carry water with a temperature above zero. Their movement is characterized by the direction from the equator to high geographical latitudes. This is the Alaska Current, Gulf Stream, Kuroshio, El Niño and others.
Cold currents carry water in the opposite direction compared to warm ones. Where a current with a positive temperature meets on their way, an upward movement of water occurs. The largest are Californian, Peruvian and others.
The division of currents into warm and cold is conditional. These definitions reflect the ratio of the water temperature in the surface layers to the ambient temperature. For example, if the flow is colder than the rest of the water mass, then such a flow can be called cold. Otherwise, it is considered a warm current.
Ocean currents largely determine climate change on our planet. Constantly mixing the water in the World Ocean, they create conditions favorable for the life of its inhabitants. And our lives directly depend on this.
