Distribution of precipitation on Earth. The role of air currents
The amount of precipitation on our planet is uneven. In some areas, they fall out regularly, other areas have not seen them for many years. How is the distribution of precipitation on Earth? What does it depend on?
Precipitation, which will be discussed in our article,called atmospheric, or hydrometeors. In fact, it is water that falls out of clouds or is deposited on the surface of the Earth in a solid or liquid form. They are divided into complex, drizzly, stormwater.
Distribution of precipitation on Earth, frequency andintensity are the main characteristics that determine the climate. They can appear in the form of frost, rain, icy rain, snow, dew, hail, etc. They are measured by the thickness of the layer in millimeters. A year on the planet, an average of about 1000 millimeters of precipitation.
In different parts of our world, the numberhydrometeors is different. The greatest number falls at the equator and in temperate zones, in the tropics and in the polar regions they are the least. Determining factors are the atmospheric pressure above the surface, the relief, the location of the terrain, the ocean currents. How are these phenomena responsible for the distribution of precipitation on Earth?
The role of air currents in the formation of precipitation
In many respects, the climate in different regions is determined byair masses. They are marine and continental and differ from each other in temperature and humidity. Sea currents are formed above the ocean, and continental above the land, so they are more dry and cold.
How is the distribution of precipitation on Earth? The role of air masses is associated with the effect of atmospheric pressure. On the whole planet it is not the same, and is placed on its surface by alternating belts.
In temperate latitudes and at the equator, the pressureLow, and the Earth heats up better. The warm air rises, and under the influence of the cold layers of the atmosphere it again descends, but already in the form of precipitation. Tropics and polar latitudes have high pressure, the air above them is dry, so there is little precipitation.
In addition, the air masses are constantly circulatingbetween the belts, the ocean and the land in the form of cyclones, anticyclones, winds. Strong rains provide the monsoon from the sea. Blowing from the land, it brings a drought. Towards the equator, rain brings tropical trade winds and winds blowing from east to west.
How does the location affect?
The specific location of the terrain is notLess impact on the distribution of precipitation on Earth than other factors. Important is the proximity of the area to the ocean, as some air masses are formed here, as well as sea currents. Remoteness from the ocean can contribute to a more dry and harsh climate, following the example of Eastern Siberia. Although, sometimes cold currents, on the contrary, provoke dry weather.
Geographic latitude is importantfactor. Features of the shape of our planet contribute to the fact that its areas are heated unevenly. This, in turn, triggers the mechanisms of atmospheric pressure and circulation of air masses. So, at the equator, the Earth heats up better, therefore, the precipitation is more abundant here than, for example, in temperate latitudes.
The close arrangement of certain currents toThe continents are also responsible for the distribution of precipitation on Earth. Depending on the temperature difference with the surrounding waters, currents in the ocean are divided into warm, cold and neutral. The first two species affect the climate and precipitation.
Warm currents transfer water from low latitudes tohigh. Above them, the air heats up and evaporates, carrying sediments on the coast. The Gulf Stream is the most powerful warm current in the world. Mostly it affects the climate of temperate latitudes. For example, in Europe it softens the winter and increases the amount of precipitation (in Dublin to 730 mm).
Cold currents move from highgeographical latitudes into lower ones. They bring on the coasts a harsh and dry climate, not missing warm and moist upper air masses. Under the influence of cold currents in temperate latitudes, on the western side of the continents, coastal deserts were formed. Thus, the Peruvian Current near Chile supports the dryness of the Atacama Desert, and the Bengal Current - the Namib Desert in Africa.
Influence of the relief
No climate-forming factor is effectiveisolated. The distribution of precipitation on the earth's surface depends on their joint work. The value has also a relief. Mountains are able to retain moist air masses, the plains, on the contrary, contribute to a uniform distribution.
Sea winds from the oceans carry moist air. Turning into clouds, he falls rain or snow on the slopes of the mountains. Thus, mountain slopes facing moist winds receive precipitation, but delay them for opposite slopes and other continent territories.
Scandinavian grief, Cordillera, Andes serveThe barrier for the western winds from the ocean, significantly drying up the climate of the continent and the eastern slopes of the mountains. The Alpine-Himalayan mountain belt receives precipitation from the equatorial monsoons from the south, but does not allow them to break further into the mainland.
Dry climate of the central regions of Australiadue to the barrier that creates the Great Dividing Range. Its eastern slopes are provided with trade winds with significant precipitation. Passing through the ridge, they overheat too much and can not form precipitation.
Distribution of precipitation in Russia
The main territory of the country is characterized bya moderate amount of precipitation - up to 500 millimeters per year. The number increases in some southern regions, for example, in the Transcaucasus. Significantly decreases in the Far North and in the steppes. Most of the precipitation falls in the summer. From west to east with the distance from the Atlantic Ocean, their abundance decreases.
Distribution of precipitation in Russiais determined by the action of temperatures, air circulation and relief. Western winds bring precipitation to the Russian plain throughout the year, most of them here (up to 900 mm / g). The summer monsoon winds from the Pacific Ocean increase precipitation in the Far East. The dryest zone is the Caspian lowland.
Winter on the western slopes of the Ural Mountainsincreased snowfall, compared with the eastern parts. This is also connected with the action of the Atlantic winds of the West. In summer, on the contrary, the eastern slopes of the mountains are full of rain.
Dry streams from the Arctic in the northern belt and drycontinental air masses from the south contribute to the fact that a large amount of precipitation falls on the territory between 55 and 65 latitudes. On both sides of this region they are much smaller.
- Distribution of precipitation in the hemispheres is valid forthe same principles, but in the Northern Hemisphere they fall slightly less. The reason for this is the ocean, since it occupies a much larger area in the Southern Hemisphere.
- The abundance of rainfall is noted in the Hawaiian Islands in the Pacific Ocean. Rainy days on the mountain Vai-Ali-ali can be up to 350 a year.
- On the Chilean coast, near the city of Antofagasta, the average rainfall per year is less than 0.1 mm.
- For the title of the dryest place on the planet, the Dry Valleys in Antarctica and the Atacama Desert in South America argue. In Antarctica, for example, some areas were not moistened for more than two million years.
- Every year, the southern spurs of the Himalayas havemore than 10 thousand millimeters of precipitation. That is ten times higher than the average. The maximum mark was fixed in the town of Cherrapunji in 1861, the rains then "dripped" 26 461 mm.