Precipitation on our planet is distributed extremely unevenly. In some areas, it rains every day and so much moisture comes to the surface of the Earth that rivers remain full throughout the year, and rainforests rise in tiers, closing sunlight... But you can also find places on the planet where not a drop of rain falls from the sky for several years in a row, dried up beds of temporary water flows cracking under the rays of the scorching sun, and scarce plants only thanks to long roots can reach the deep layers groundwater... What is the reason for this injustice? The distribution of precipitation on the globe depends on how many clouds containing moisture form over a given area or how much the wind can bring. The air temperature is very important, because intensive evaporation of moisture occurs precisely when high temperature... The moisture evaporates, rises and clouds form at a certain height.
The air temperature decreases from the equator to the poles, therefore, the amount of precipitation is maximum in equatorial latitudes and decreases towards the poles. However, on land, the distribution of precipitation depends on a number of additional factors.
There is a lot of precipitation over coastal areas, and the amount decreases with distance from the oceans. More rainfall on windy slopes of mountain ranges and much less on leeward slopes. For example, on Atlantic coast Norway in Bergen receives 1,730 mm of precipitation per year, and in Oslo (behind the ridge) only 560 mm. Low mountains also affect the distribution of precipitation - on the western slope of the Urals, in Ufa, an average of 600 mm of precipitation falls, and on the eastern slope, in Chelyabinsk, - 370 mm.
The distribution of precipitation is also influenced by the currents of the World Ocean. Over the areas near which warm currents pass, the amount of precipitation increases, since the air heats up from the warm water masses, it rises and clouds with sufficient water content are formed. Over the territories near which cold currents pass, the air cools down, descends, clouds do not form, and much less precipitation falls.
The largest number precipitation falls in the Amazon basin, off the coast of the Gulf of Guinea and in Indonesia. In some parts of Indonesia, maximum values reach 7000 mm per year. In India, in the foothills of the Himalayas, at an altitude of about 1300 m above sea level, there is the most rainy place on Earth - Cherrapundzhi (25.3 ° N and 91.8 ° E), here an average of more than 11,000 mm of precipitation falls per year. Such an abundance of moisture is brought to these places by the humid summer southwestern monsoon, which rises along the steep slopes of the mountains, cools and pours into powerful rain.
Today, within the framework of our article, we want to answer questions regarding atmospheric precipitation... This is quite a common occurrence when from the sky it's raining or snow, but not all people know about the nature of such phenomena.
Why precipitation occurs on Earth
First of all, you need to deal with what is generally called precipitation. And the answer to this question is very simple, because it is all water in different states, falling from the clouds or precipitating from the air, and directed to earth surface... Precipitation can occur in both solid and liquid states.
The procedure for the formation of precipitation is quite simple for explanation and understanding, although in itself it turns out to be, perhaps, one of the most complex processes taking place on our planet. The rain that we have the opportunity to see periodically is the result of water evaporation from the Earth's surface. After evaporation, water enters the atmosphere, which leads to the inevitable formation of rain clouds. When these clouds become very voluminous, the collected water vapor condenses - it starts to rain.
Why atmospheric precipitation on Earth is distributed very unevenly
A well-known and widespread factor is that precipitation is not distributed quite evenly across our planet. So, for example, we know that there are zones in which there are rainy seasons, when for us, for example, such a concept is something unprecedented (by the way, you can check whether precipitation and other weather data in your region will be available on the Meteoprognosis website ). A similar phenomenon occurs associated with uneven distribution precipitation, due to several main factors at once. Of these, the following should be highlighted:
- The location of the site of the planet relative to the world's oceans. Of course, in those places in which the accumulation of water bodies, rivers, lakes and oceans is more serious, the process of vaporization becomes higher, which inevitably leads to a fairly frequent and very abundant precipitation;
- Geographic location site of the planet. As we have already noted in the framework of the articles on our website, the equator of the Earth is the closest to the Sun of all parts of our planet. Accordingly, the heating of the planet there is stronger, which also leads to a strong and abundant evaporation of water, which accumulates in the clouds and, as a result, leads to precipitation instead of rain. There, the amount of precipitation is several times higher than the indicators we are used to.
In addition to the reasons we have noted, among the main factors affecting the uneven distribution of precipitation, it is also necessary to highlight the terrain, and the location of pressure belts, and from some other, not so significant factors.
B) seismic belts.
A) external forces;
B) internal forces;
C) weathering.
6.Trades are winds:
A) equatorial;
B) subtropical;
C) tropical.
A) ebb and flow;
B) wind waves;
C) ocean currents.
A) clockwise;
A) cooling;
B) warming;
C) neutral.
1. The thickness reaches 70 km, there are three layers: basalt, granite and sedimentary. What are we talking about? A) about the oceanic crust; B) about the continental crust; C) about the lithospheric plate.
2.The ancient mainland in the southern hemisphere was called:
A) Laurasia;
B) Pangea;
C) Gondwana.
3. The speed of movement of lithospheric plates: A) 1-2 cm; B) 1-10 cm; C) 15-20 cm per year.
4.The border areas between lithospheric plates are called:
A) seismic belts;
B) faults;
B) plates.
5. Vast plains on earth correspond to:
A) folded belts;
B) platforms;
B) depressions.
6. What forces are used to create ravines on Earth, river valleys, dunes, hills:
A) internal;
B) external.
7. Most of the short-wavelength cosmic radiation, destructive for all living things, does not pass through the atmosphere: A) carbon dioxide; B) the ozone layer; B) water vapor.
8. Constant winds on Earth arise: A) due to belts with different atmospheric pressure;
B) due to the difference in temperature in the upper atmosphere; B) due to the cooled air.
9. They occupy a vast territory, retain their properties for a long time and determine the weather of those places where they come: A) high pressure belt; B) air mass;
B) underlying surface.
10. In what climatic zone come in summer air masses from the equatorial, and in winter - from the tropical zone? A) subequatorial; B) equatorial; C) tropical.
11. Throughout the year, the same air masses dominate here, all 4 seasons of the year are clearly manifested: A) the subarctic belt; B) temperate zone;
V) sub tropical belt.
12. They are equatorial, tropical, surface, deep, coastal, etc. What it is? A) nekton; B) water masses; C) ocean currents.
13. What is the regularity of the movement of ocean currents in the northern hemisphere:
A) clockwise;
B) counterclockwise.
14. Organisms unable to resist the movement of water:
A) benthos;
B) nekton;
C) plankton.
15. A plot of the earth's surface, within which all components of nature are interconnected, interdependent and interpenetrate into each other:
A) natural area;
B) altitude zone;
C) natural complex.
Grade 7 Topic: "The main features of the nature of the Earth" 2 var. FULL NAME_______________
1.Single ancient mainland called: A) Laurasia; B) Pangea; C) Gondwana.
2. At the base of modern continents are: A) platforms; B) folded belts;
B) seismic belts.
3. Continental ledges and oceanic trenches are formed due to:
A) external forces;
B) internal forces;
C) weathering.
4. The air temperature on the ground is distributed due to: A) the distribution of belts atmospheric pressure; B) geographical latitude; C) downward air movement.
5. What determines the distribution of precipitation on Earth: A) from the belts of atmospheric pressure;
B) from the geographical latitude; B) from constant winds.
6.Trades are winds:
A) western latitudes; B) high latitudes; C) winds blowing towards the equator.
7. In what zone do air masses come from the tropical in summer, and from the temperate in winter?
A) equatorial;
B) subtropical;
C) tropical.
8. All year round it is hot and humid here, because the same air masses dominate:
A) equatorial belt; B) subequatorial belt; C) the tropical belt.
9. Their education is associated with constant winds and the deflecting force of the Earth's rotation around its axis:
A) ebb and flow;
B) wind waves;
C) ocean currents.
10. What is the regularity of the movement of ocean currents in the southern hemisphere:
A) clockwise;
B) counterclockwise.
11. Organisms actively moving in water: A) nekton; B) benthos; C) plankton.
12. Main mechanism geographic envelope: A) influence on her Solar energy;
B) the circulation of energy and substances; C) the substance is in 3 states.
13 .. The Gulf Stream affects the climate of Europe:
A) cooling;
B) warming;
C) neutral.
14. Change natural areas in the mountains they call:
A) natural zoning; B) latitudinal zoning
Precipitation - water in a liquid or solid state, falling out of clouds or deposited from the air on the earth's surface.
Rain
Under certain conditions, cloudy drops begin to merge into larger and heavier ones. They can no longer be held in the atmosphere and fall to the ground in the form rain.
Hail
It happens that in summer the air rises quickly, picks up rain clouds and carries them to a height where the temperature is below 0 °. Raindrops freeze and fall out as hail(fig. 1).
Rice. 1. Origin of the city
Snow
V winter time in temperate and high latitudes, precipitation falls in the form snow. Clouds at this time do not consist of water droplets, but of the smallest crystals - needles, which, joining together, form snowflakes.
Dew and frost
Precipitation falling on the earth's surface not only from clouds, but also directly from the air is dew and frost.
The amount of precipitation is measured by a rain gauge or a rain gauge (Fig. 2).
Rice. 2. The structure of the rain gauge: 1 - outer body; 2 - funnel; 3 - container for collecting oxen; 4 - dimensional tank
Classification and types of precipitation
Precipitation is distinguished by the nature of precipitation, origin, physical condition, seasons of precipitation, etc. (Fig. 3).
By the nature of precipitation, precipitation is heavy, heavy and drizzling. Heavy rainfall - intense, short, cover a small area. Overhead precipitation - medium intensity, uniform, long-term (can last for days, capturing large territories). Drizzling precipitation - fine-droplet precipitation falling on an insignificant area.
Precipitation is distinguished by origin:
- convective - characteristic of the hot zone, where heating and evaporation are intense, but often occur in the temperate zone;
- frontal - are formed when two air masses meet with different temperatures and fall out of the warmer air. Typical for temperate and cold zones;
- orographic - fall on the windward slopes of the mountains. They are very abundant if the air comes from the side. warm sea and has a high absolute and relative humidity.
Rice. 3. Types of precipitation
Comparing on climate map annual quantity precipitation on the Amazonian lowland and in the Sahara desert, one can be convinced of their uneven distribution (Fig. 4). How can this be explained?
Precipitation brings moist air masses that form over the ocean. This is clearly seen in the example of territories with monsoon climate... The summer monsoon brings a lot of moisture from the ocean. And there are continuous rains over land, like on the Pacific coast of Eurasia.
Constant winds also play a large role in the distribution of precipitation. Thus, trade winds blowing from the continent bring dry air to northern Africa, where the most vast desert the world - the Sahara. Westerly winds bring rains to Europe from the Atlantic Ocean.
Rice. 4. Average annual distribution of precipitation on the Earth's land
As you already know, sea currents affect precipitation in the coastal parts of the continents: warm currents contribute to their appearance (the Mozambican current off the eastern coast of Africa, the Gulf Stream off the coast of Europe), cold ones, on the contrary, prevent precipitation ( Peruvian current off the western coast of South America).
The relief also affects the distribution of precipitation, for example, the Himalayan mountains do not allow wet winds blowing from Indian Ocean... Therefore, their southern slopes sometimes receive up to 20,000 mm of precipitation per year. Wet air masses, rising along the slopes of mountains (ascending currents of air), are cooled, saturated, and precipitation falls out of them. The territory north of the Himalayan mountains resembles a desert: only 200 mm of precipitation falls there per year.
There is a relationship between the belts and the amount of precipitation. At the equator - in the belt low pressure- constantly heated air; rising up, it cools and saturates. Therefore, many clouds form in the equator area and there are heavy rains. A lot of precipitation also falls in other regions of the world, where low pressure prevails. Wherein great importance has an air temperature: the lower it is, the less precipitation falls.
Downward air currents prevail in high pressure belts. As the air sinks, it heats up and loses its saturation state. Therefore, at latitudes of 25-30 °, precipitation is rare and in small quantities. There is also little rainfall in high pressure areas near the poles.
Absolute maximum precipitation registered on about. Hawaii (Pacific Ocean) - 11,684 mm / year and Cherrapunji (India) - 11,600 mm / year. The absolute minimum is in the Atacama Desert and in the Libyan Desert - less than 50 mm / year; sometimes precipitation does not fall for years at all.
The characteristic of the moistening of the territory is moisture factor- the ratio of annual precipitation and evaporation for the same period. The moisture coefficient is designated by the letter K, the annual precipitation is by the letter O, and the evaporation is by I; then K = O: I.
The lower the moisture coefficient, the drier the climate. If the annual amount of precipitation is approximately equal to the evaporation rate, then the moisture coefficient is close to unity. In this case, moisture is considered sufficient. If the moisture index more than one then humidification excess, less than one - insufficient. With a humidification coefficient less than 0.3, humidification is considered meager... Areas with sufficient moisture include forest-steppe and steppe, areas with insufficient moisture - deserts.
The amount of precipitation on our planet is uneven. In some areas, they fall regularly, other territories have not seen them for many years. How is precipitation distributed on Earth? What does it depend on?
Precipitation
Precipitation, which will be discussed in our article, is called atmospheric, or hydrometeors. In fact, it is water that falls out of clouds or is deposited on the surface of the Earth in solid or liquid form. They are divided into overlying, drizzling, stormy ones.
The distribution of precipitation on Earth, frequency and intensity are the main characteristics that determine the climate. They can appear in the form of frost, snow, dew, hail, etc. They are measured by the layer thickness in millimeters. On average, about 1000 millimeters of precipitation falls on the planet annually.
V different corners of our world, the number of hydrometeors is different. The largest amount falls at the equator and in the tropics and polar regions there are the least of them. The determining factors are atmospheric pressure above the surface, relief, location of the terrain. How are these phenomena responsible for the distribution of precipitation on Earth?
The role of air currents in the formation of precipitation
To a large extent, the climate in different regions is determined. They are marine and continental and differ from each other in temperature and humidity. Sea currents are formed over the ocean, and continental currents over land, so they are drier and colder.
How is precipitation distributed on Earth? The role of air masses is related to the effect of atmospheric pressure. It is not the same throughout the planet, and is located on its surface in alternating belts.
V temperate latitudes and at the equator the pressure is low, and the Earth heats up better. Warm air rises up, and under the influence of cold layers of the atmosphere descends again, but in the form of precipitation. The tropics and polar latitudes have high pressure, the air above them is dry, so there is little precipitation.
In addition, air masses are constantly circulating between belts, the ocean and land in the form of cyclones, anticyclones, and winds. Heavy rains provides monsoon from the sea. Blowing from the land side, it brings drought. To the equator, rain is brought by tropical trade winds and winds blowing from east to west.
How does location affect?
The specific location of the terrain has no less influence on the distribution of precipitation on Earth than other factors. The proximity of the terrain to the ocean is important, since some air masses are formed here, as well as sea currents. Distance from the ocean can contribute to a drier and harsher climate, like Eastern Siberia... Although, sometimes cold currents, on the contrary, provoke dry weather.
Geographic latitude is an important factor. The peculiarities of the shape of our planet contribute to the fact that its parts 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 best, therefore, precipitation is more abundant here than, for example, in temperate latitudes.
Sea currents
The close location of some currents to the continents is also responsible for the distribution of precipitation on Earth. Depending on the difference in temperature with the surrounding waters, currents in the ocean are divided into warm, cold and neutral. The first two types have an impact on climate and precipitation.
In winter on the western slopes Ural mountains increased snowfall compared to eastern parts... It is also associated with the action of the Atlantic westerly winds... In summer, on the contrary, the eastern slopes of the mountains are full of precipitation.
Dry streams from the Arctic in the northern strip and dry continental air masses from the south contribute to the fact that a large number of precipitation falls between 55 and 65 latitudes. There are significantly fewer of them on both sides of this area.
Records
- The distribution of precipitation in the hemispheres works according to the same principles, but in the Northern Hemisphere it falls slightly less. This is due to the ocean, since in the Southern Hemisphere it occupies a much larger area.
- The abundance of precipitation is noted at Hawaiian Islands v Pacific... There are up to 350 rainy days on Mount Wai-Ali-Ali a year.
- On the Chilean coast, near the city of Antofagasta, the average annual rainfall is less than 0.1 mm.
- The Dry Valleys in Antarctica and the Atacama Desert in South America... In Antarctica, for example, some areas have not been moistened for more than two million years.
- More than 10 thousand millimeters of precipitation fall on the southern spurs of the Himalayas annually. Which is ten times the average. The maximum mark was recorded in the town of Cherrapunji in 1861, then the rain "dripped" 26 461 mm.
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