23.06.2020

Thermal belts of the planet. Thermal belt. Cold climate zone

Thermal belts - This various areas the globe, which receive an unequal amount of heat from the sun. On the globe five heat zones: one hot, two temperate and two cold.

In the hot zone, the sun stands overhead, its rays fall down almost vertically, the duration of day and night is approximately the same throughout the year. In the cold zone, the sun never rises high, its rays almost glide over the surface of the earth, the winter day is very short. The temperate zone lies between hot and cold. Summer in temperate zone the sun is high in the sky, the day is long. In winter, the days are short, the sun does not rise high and almost does not warm the earth.

Most solar heat is received by the area located on both sides of the Equator, between the North and South tropics. It is hot there all year round, and snow never falls on the plains. This territory, stretching from north to south for more than 5 thousand km, is called hot belt.material from the site

Significantly less solar heat is received by the regions of the globe north of the Arctic Circle and south of the Antarctic Circle. Here all year round cold and for short summer The snow and ice don't even have time to melt. The sun does not appear at all for several months, and in summer it is so low that its rays seem to glide over the surface of the Earth (Fig. 129). The area north of the Arctic Circle is called northern cold belt, and south of the Antarctic Circle - southern cold belt.

Between the Arctic Circle and the Northern Tropic stretches northern temperate zone. In the southern hemisphere between the Antarctic Circle and the Tropic of the South is southern temperate zone.

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During the day, the air temperature changes. The most low temperature observed before sunrise, the highest - at 14-15 hours.

To determine average daily temperature it is necessary to measure the temperature four times a day: at 1 am, at 7 am, at 1 pm, at 7 pm. The arithmetic mean of these measurements is the average daily temperature.

The air temperature changes not only during the day, but also throughout the year (Fig. 138).

Rice. 138. Head change in air temperature at a latitude of 62 ° N. sh.: 1 - Torshavn Denmark (marine tyne), medium annual temperature 6.3 °C; 2- Yakutsk (continental type) - 10.7 °С

Average annual temperature is the arithmetic average of temperatures for all months of the year. It depends on geographical latitude, the nature of the underlying surface, and the transfer of heat from low to high latitudes.

The Southern Hemisphere is generally colder than the Northern Hemisphere due to the ice and snow covered Antarctica.

The warmest month of the year in the Northern Hemisphere is July, while the coldest month is January.

Lines on maps connecting places with the same air temperature are called isotherms(from the Greek isos - equal and therme - heat). Their complex location can be judged from the maps of January, July and annual isotherms.

The climate at the corresponding parallels of the Northern Hemisphere is warmer than the corresponding parallels of the Southern Hemisphere.

The highest annual temperatures on Earth are observed on the so-called thermal equator. It does not coincide with the geographic equator and is located at 10 ° N. sh. This is because in the Northern Hemisphere large area occupied by land, and in the Southern Hemisphere, on the contrary, by the oceans, which expend heat on evaporation, and besides this, the influence of ice-covered Antarctica affects. The average annual temperature at the parallel is 10° N. sh. is 27 °C.

Isotherms do not coincide with parallels despite the fact that solar radiation is distributed zonally. They bend, moving from the mainland to the ocean, and vice versa. So, in the Northern Hemisphere in January over the mainland isotherms deviate to the south, and in July - to the north. This is due to the unequal conditions for heating land and water. In winter, land cools, and in summer it heats up faster than water.

If we analyze isotherms in the Southern Hemisphere, then in temperate latitudes their course is very close to parallels, since there is little land there.

In January, the highest air temperature is observed at the equator - 27 ° C, in Australia, South America, central and southern parts of Africa. The lowest temperature in January was recorded in the northeast of Asia (Oymyakon, -71 °С) and at the North Pole -41 °С.

The "warmest parallel of July" is the parallel of 20°N. with a temperature of 28 ° C, and the coldest place in July is the south pole with an average monthly temperature-48 °С.

The absolute maximum air temperature was recorded in North America(+58.1 °С). The absolute minimum air temperature (-89.2 °C) was recorded at the Vostok station in Antarctica.

Observations revealed the existence of daily and annual fluctuations in air temperature. The difference between the highest and lowest air temperatures during the day is called daily range, and during the year annual temperature range.

The daily temperature amplitude depends on a number of factors:

latitude of the area - decreases when moving from low to high latitudes;
the nature of the underlying surface - it is higher on land than over the ocean: over the oceans and seas, the daily temperature amplitude is only 1-2 ° C, and over the steppes and deserts it reaches 15-20 ° C, since the water heats up and cools down more slowly than land ; in addition, it increases in areas with bare soil;
terrain - due to lowering into the valley of cold air from the slopes;
cloud cover - with its increase, the daily temperature amplitude decreases, since clouds do not allow the earth's surface to become very hot during the day and cool at night.

The magnitude of the daily amplitude of air temperature is one of the indicators of the continentality of the climate: in deserts, its value is much greater than in areas with a maritime climate.

Annual temperature amplitude has patterns similar to the daily temperature amplitude. It depends mainly on the latitude of the area and the proximity of the ocean. Over the oceans, the annual temperature amplitude most often does not exceed 5-10 °C, and over the interior regions of Eurasia - up to 50-60 °C. Near the equator, average monthly air temperatures differ little from each other throughout the year. At higher latitudes, the annual temperature amplitude increases, and in the Moscow region it is 29 °C. At the same latitude, the annual temperature amplitude increases with distance from the ocean. In the equatorial zone above the ocean, the annual temperature amplitude is only G, and over the continents - 5-10 °.

The different conditions for heating water and land are explained by the fact that the heat capacity of water is twice that of land, and with the same amount of heat, land heats up twice as fast as water. On cooling, the opposite happens. In addition, when heated, water evaporates, while a significant amount of heat is consumed. It is also important that on land heat is distributed practically only in the upper soil layer, and only a small part of it is transferred to the depth. In the seas and oceans, a considerable thickness is being heated. This is facilitated by vertical mixing of water. As a result, oceans accumulate heat much more than land, retain it longer and spend it more evenly than land. The oceans heat up more slowly and cool more slowly.

The annual temperature amplitude in the Northern Hemisphere is 14 °С, and in the Southern - 7 °С. For the globe, the average annual air temperature near the earth's surface is 14 °C.

Thermal belts

The uneven distribution of heat on the Earth, depending on the latitude of the place, allows us to distinguish the following thermal belts, whose boundaries are isotherms (Fig. 139):

the tropical (hot) zone is located between the annual isotherms + 20 °С;
temperate zones of the Northern and Southern hemispheres - between the annual isotherms +20 °С and the isotherm of the warmest month +10 °С;
the polar (cold) belts of both hemispheres are located between the isotherms of the warmest month +10 °С and О °С;
the belts of eternal frost are limited by the 0°C isotherm of the warmest month. This is the realm of eternal snow and ice.

Rice. 139. Thermal belts of the Earth

The heating of the soil and the illumination of any territory are directly dependent on the thermal zone in which it is located. This, in turn, is affected by geographic latitude.

What are thermal belts?

Solar heat arrives at high and low latitudes differently. This is due to the fact that the angles of inclination of the rays of our star to the surface of the Earth differ. This is where the concept of climate comes from. The further north a territory is located, the less heat it receives per unit of surface. This is due to the lower rise of the sun at noon.

The very word "climate" in Greek means "slope". It depends on the geographical location of a particular area and is determined by atmospheric pressure, humidity and average temperature air throughout the year.
There are three thermal zones on Earth. It is temperate, hot and cold. Each of them has its own distinctive features.

Cold climate zone

It is located in the region of the Arctic Circle, located both in the Northern and in South Pole of our planet are as far as possible from the equator, and in connection with this, the sun sends only oblique rays to them. That is why in these areas the earth heats up very weakly.

Winters in these areas are long and harsh, while summers are short and cool. There are several months of the year when the sun's rays do not reach the Arctic Circle at all. This period is the polar night. The temperature at this time here can drop to eighty-nine degrees.

Temperate zone

These thermal zones are also located in two hemispheres. In their territories, oblique sun rays slightly warm the earth in winter. In summer, the sun illuminates them more intensively. There are moderate thermal zones between the Arctic Circle and the two parallels. To the north is Cancer and to the south is the Tropics of Capricorn.

The sun in these belts is never at its zenith. Therefore, it does not heat the soil and air very much. Temperate thermal zones are characterized by a clear delineation of seasons. Winter, summer, autumn and spring are observed here. At the same time, the temperature character of these seasons is not the same. The closer an area is to the Arctic Circle, the colder the winter on its territory. Conversely, summers are warmer and longer as the territory approaches the tropics.

hot belt

Above this zone, the sun always rises high and sends direct rays to it. That is why there is always a high temperature here. The dominance of this belt is observed in the tropics. winter period in this area is the rainy season, and summer is characterized by drought.

The hot thermal belt of the Earth is located between the South and along the equator. Twice during the year, namely at noon on June 22 and December 22, the sun's rays fall in this zone almost vertically, that is, at an angle of ninety degrees. The air warms up from the surface of the soil. That is why this area is hot all year round. Palm trees grow only within this belt.

Thus, the thermal belts of the world are represented by five zones. They include two cold, two moderate and one hot. Sometimes in cold thermal zones a region of eternal frost is isolated. It is located directly near the poles, and mean annual temperature here it does not rise above zero.

The thermal zones of Russia are cold and temperate. The north of the country is characterized by a harsh climate. At the same time, a change of polar winter and polar summer is observed. The more southern territories have a mild climate and pronounced seasonality.

The nature of the cold thermal zone

The polar zones of our planet are constantly covered with snow and ice. These are the coldest places on earth. The Arctic, which belongs to the polar zone, passes through Alaska. It includes the island of Greenland. Located in the polar zone north of Canada and Russia.

Antarctica, located in the Southern Hemisphere, is the southern polar zone. The continent of Antarctica is located there.

The cold thermal zone, which is characterized by a lack of heat, does not have forests. The soil in these areas is swampy. In some places you can find areas of permafrost. The most severe climate is observed at the poles. There are sea or continental ice. Vegetation is usually absent or represented by lichens and moss.

They live mostly in the cold zone. migratory birds. Especially a lot of them on the islands Arctic Ocean. There are also animals in this area. They migrate from more southerly areas during the summer season. The fauna is represented by owls and arctic foxes, polar mice and polar bears, walruses, seals and penguins.

The nature of the temperate thermal zone

Territories of these climatic zones get more light and heat. It's not such a harsh winter here. Summer in the temperate zone is not very hot. The sun is never at its zenith over these areas. Therefore, the climate of the temperate zones is mild, and its changes from warm to cold occur gradually. There are four seasons in these zones: summer, spring, winter and autumn.

The temperate thermal zone passes through the territory of Great Britain, Europe. It contains North Asia and North America. In the Southern Hemisphere, the temperate zone is located on the waters of three oceans. Thus, 98% of its area is occupied by water. The temperate zone in the Southern Hemisphere runs through Australia and New Zealand. It covers the south South Africa And South America.

The nature of this thermal zone is very diverse. These are taiga, semi-deserts and deserts, as well as steppes.

Fairly homogeneous animal world. It is mainly represented by forest animals that lead a sedentary lifestyle. IN lesser degree fauna are widespread open area- steppes and deserts.

The nature of the hot thermal zone

Most of Africa is located in this zone. In the hot zone is the south of India and Asia. This zone includes Central America, New Guinea, northern Australia and northern South America.

There is no seasonality near the equator. Throughout the year, these areas are very warm and humid.

The hot thermal zone is characterized by savannahs, evergreens and light forests. Some areas are semi-deserts and deserts.
The animal world is remarkable for its extraordinary diversity. These are birds of prey and running, hippos and antelopes, elephants and zebras, buffaloes, etc.

Thermal belts

(temperature belts), zones with certain temperature conditions located along parallels around the globe (sometimes with breaks). They are distinguished in accordance with the established criteria: according to the position on the map of isotherms in some months, according to the number of months of the year from cf. a swarm within certain limits, etc. For example, according to the classification of V. P. Köppen, subtropical, temperate, cold and polar thermal zones are distinguished.

Geography. Modern illustrated encyclopedia. - M.: Rosman. Under the editorship of prof. A. P. Gorkina. 2006 .

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1. Thermal belts of the Earth

Uneven heating of the earth's surface causes different temperatures air at different latitudes. Latitudinal bands with certain air temperatures are called thermal zones. The belts differ in the amount of heat coming from the Sun. Their stretching depending on the distribution of temperatures is well illustrated by isotherms (from the Greek "iso" - the same, "therma" - heat). These are lines on a map that connect points with the same temperature.

The hot belt is located along the equator, between the Northern and Southern tropics. It is limited on both sides of the 20 0С isotherms. Interestingly, the boundaries of the belt coincide with the boundaries of the distribution of palm trees on land and corals in the ocean. Here earth's surface receives the most solar heat. Twice a year (December 22 and June 22) at noon, the sun's rays fall almost vertically (at an angle of 900). The air from the surface gets very hot. Therefore, it is hot there throughout the year.

The temperate zones (in both hemispheres) adjoin the hot zone. They stretched in both hemispheres between the Arctic Circle and the tropic. The sun's rays there fall on the earth's surface with a certain slope. Moreover, the further north, the greater the slope. Therefore, the sun's rays heat the surface less. As a result, the air heats up less. That is why temperate zones are colder than hot ones. The sun is never at its zenith there. Clearly expressed times years: winter, spring, summer, autumn. Moreover, the closer to the Arctic Circle, the longer and colder the winter. The closer to the tropic, the longer and warmer the summer. The temperate zones from the side of the poles are limited by the isotherm of the warm month of 10 0С. It is the limit of the distribution of forests.

The cold zones (Northern and Southern) of both hemispheres lie between the isotherms of 10 0С and 0 0С of the warmest month. The sun there in winter for several months does not appear above the horizon. And in the summer, although it does not go beyond the horizon for months, it is very low above the horizon. Its rays only glide over the surface of the Earth and heat it weakly. The Earth's surface not only heats but also cools the air. Therefore, the temperatures there are low. Winters are cold and harsh, while summers are short and cool.

Two belts of eternal cold (northern and southern) are surrounded by an isotherm with temperatures of all months below 0 0C. This is the realm of eternal ice.

So, the heating and lighting of each locality depends on the position in the thermal zone, that is, on the geographical latitude. The closer to the equator, the greater the angle of incidence of the sun's rays, the more the surface heats up and the air temperature rises. Conversely, with distance from the equator to the poles, the angle of incidence of the rays decreases, respectively, the air temperature decreases.

It is important to remember that the lines of the tropics and polar circles outside the thermal zones are taken conditionally. Since in reality the air temperature is also determined by a number of other conditions (see the article main and transitional climatic zones).

1.1 Roast

Equatorial belt - zone low pressure, ascending currents of air, weak winds. Temperatures are high throughout the year (about +28 °C), air humidity is high. There is a lot of precipitation - about 2000 mm. seasonal fluctuations average monthly temperatures and little rainfall.

Subequatorial belts are characterized by seasonal change air masses: summer monsoon brings hot and humid equatorial air, dry continental tropical air dominates in winter. Such a climate with wet summers and dry winters is called monsoonal.

Tropical zones are characterized by an arid (dry) climate, they have the greatest deserts in the world: Sahara, Arabian, Australian. The air temperature ranges from +20 °c in summer to +15 °c in winter.

1.2 Moderate

In subtropical zones, air masses change from tropical in summer to moderate in winter, and temperatures are above zero throughout the year. However, short-term drops in temperature to negative values and even snowfall. On the plains, the snow melts quickly, and in the mountains it can lie for several months. In the inland areas, the climate is arid, with hot (about +30 °C) dry summers, cool (0...+5 °C), relatively humid (200-250 mm) winters. Change of air masses and frequent passage atmospheric fronts defines unsettled weather. Due to insufficient moisture, landscapes of deserts, semi-deserts, and dry steppes predominate here. Special sharply continental climate with cool summers, harsh winter and insignificant rainfall stands out the largest and highest (4-5 km) highlands of the world Tibet with high-mountainous deserts.

In the Southern Hemisphere, where there are no large continents, and only a narrow part of South America, the island of Tasmania and Southern New Zealand enter the temperate zone, the climate is oceanic mild with warm winter and cool summers with uniform heavy (about 1000 mm) precipitation. And only in Patagonia the climate is transitional to continental, and moisture is insufficient.

In the Northern Hemisphere, on the contrary, vast land masses dominate and a whole spectrum of climates differing in degree of continentality is developed. From west to east - from temperate to sharply continental climate - daily and seasonal temperature amplitudes increase, and annual precipitation decreases from 700-600 mm to 300 mm and even to 200-100 mm in the Middle and Central Asia. More precipitation falls in summer than in winter, and this difference is more significant in the center of the continents, especially in Eastern Siberia, due to a very dry anticyclonic winter.

In the temperate zone, the northern part is distinguished with cool summers and relatively severe winters, and the southern part with warm summer and relatively mild winters. July temperatures vary from -4...-10 °c to +12 °c in the north and up to +30 °c in the south, January temperatures from -5 °c in the west to -25...- 30 °c in the center of the continents, in Yakutia even below -40 °c.

1.2 Cold

The subarctic and subantarctic belts are characterized by a seasonal change of air masses: in the summer of the MT, in the winter of the AB. In the north of Eurasia and North America, the climate is continental and sharply continental with cool, damp summers with temperatures below +10...+12 °C and long, severe (up to -40...-50 °C) winters with little snow and large annual temperature ranges. . In the area of Oymyakon there is a cold pole of the Northern Hemisphere and the entire planet - (-78 ° C). Such conditions contribute to the maintenance of ubiquitous permafrost. There is little precipitation (200-100 mm), however, due to low temperatures, moisture is excessive. The tundra and forest-tundra prevailing here are heavily swamped.

The maritime climate of the northern and southern coasts is characterized by cool (+3...+5 °c) damp summers, relatively mild (-10...-15 °c) winters, floating sea and continental ice, constant fogs with significant low temperatures rainfall (up to 500 mm). Tundra is widespread along the coasts of the continents and on the islands.

In the Arctic (Greenland and the islands of the Canadian archipelago) and Antarctic belts(Antarctica), dominated continental climate. These are the coldest regions of the Earth - the thermometer does not rise above zero all year, and at the inland Antarctic station "Vostok" an absolute minimum temperature of -89.2 ° C was recorded (but the station "Vostok" is located at an altitude of 3488 m). Rainfall is less than 100 mm. Here you can hardly see anything other than icy deserts. The Arctic has an oceanic climate. Negative temperatures prevail, but during the polar day it can get warmer up to +5 °C. Precipitation is also low, the islands are characterized by tundra.

2.Air masses

Large air masses in the troposphere, commensurate in size with the mainland or ocean and having more or less the same properties (temperature, humidity, transparency, dust content, etc. - approx. from geoglobus.ru), are called air masses. They extend upwards for several kilometers, reaching the boundaries of the troposphere.

Air masses move from one region of the globe to another, determining the climate and weather in a given area. Each air mass has properties characteristic of the area over which it formed.

Moving to other territories, it carries with it its own weather regime. But passing over a territory with different properties, the air masses gradually change, transform, acquiring new qualities.

Depending on the regions of formation, four types of air masses are distinguished: arctic (in the southern hemisphere - antarctic), temperate, tropical and equatorial. All types are divided into subtypes with their own characteristic properties. Continental air masses form over the continents, and oceanic air masses form over the oceans. Moving along with the belts atmospheric pressure during the year, air masses occupy not only the permanent zones of their stay, but seasonally dominate in neighboring, transitional climatic zones. In the process of general circulation of the atmosphere, air masses of all types are interconnected.

Air masses that move from a colder earth's surface to a warmer one and which have a lower temperature than the surrounding air are called cold air masses. They bring cooling, but they themselves warm up from below from the warm earth's surface, while powerful cumulus clouds form and heavy rains fall. Especially strong cold snaps occur in temperate latitudes during the invasion of cold masses from the Arctic and Antarctica - approx. from geoglobus.ru. Cold air masses sometimes reach the southern regions of Europe and even North Africa, but are most often delayed by the mountain ranges of the Alps. In Asia, arctic air is freely distributed over vast territories, up to the mountain ranges of southern Siberia. In North America, the mountain ranges are located meridianally, so cold Arctic air masses penetrate to the Gulf of Mexico.

Masses of air that have a higher temperature than the surrounding air and come to a colder earth's surface are called warm air masses. They bring warming, and they themselves are cooled from below, thus forming stratus clouds and fogs. In summer, warm tropical air masses from North Africa sometimes penetrate to the northern regions of Europe and significantly increase the temperature (sometimes up to +30 ° C).

Local, or neutral, air mass is called the mass located in thermal equilibrium with its environment, that is, day after day, retaining its properties. The changing air mass can be both warm and cold, and upon completion of the transformation, it becomes local.

Where air masses meet different types, atmospheric fronts are formed.

Moderate air masses form in temperate latitudes. Those that form over the continent are characterized by low temperature and low moisture content in winter and bring clear and frosty weather. In summer, continental temperate air masses are dry and hot. Moderate air masses formed over the ocean are warm and humid. In winter they bring thaws, and in summer - cold snap and precipitation.

Arctic and Antarctic air masses form over the ice surface of polar latitudes. They are characterized by low temperature and a small amount of moisture. They significantly lower the temperature of the areas they invade. In summer, moving to the center of Eurasia, these air masses gradually heat up, dry out even more and become the cause of dry winds in southern regions West Siberian lowland.

Tropical air masses are hot at any time of the year. The marine subtype of tropical air masses is characterized by high humidity, while the continental subtype is dry and dusty. Over the oceans in the tropics, the trade winds dominate all year - approx. from geoglobus.ru. The air masses formed in these areas are characterized by moderately high temperatures from +20 to +27 °С in summer and cool temperatures up to +10 +15 °С in winter. In the districts tropical deserts Extremely dry air masses form over the continents with average temperatures of +26 +40 °C.

Equatorial air masses are formed in equatorial latitudes. They possess high temperature and high humidity, regardless of where they formed - over the mainland or over the ocean. The average temperatures of equatorial air masses in all months of the year range from +24 to +28 °С. Since evaporation is high in these areas, the absolute humidity is also high, and relative humidity even in the driest months of the year above 70%.

3. Precipitation

thermal belt air atmospheric

Their education

Precipitation is any moisture that has fallen from the atmosphere onto the earth's surface. These include rain, snow, hail, dew, frost. Precipitation can fall both from clouds (rain, snow, hail) and from the air (dew, frost).

The main condition for education precipitation is cooling warm air, leading to the condensation of the vapor contained in it.

When warm air rises and cools, clouds are formed, consisting of water droplets. Colliding in a cloud, the drops are connected, their mass increases. The bottom of the cloud turns blue and it rains. At negative air temperatures, water droplets in the clouds freeze and turn into snowflakes. Snowflakes stick together into flakes and fall to the ground. During a snowfall, they can melt a little, and then it snows. It happens that air currents repeatedly lower and raise frozen drops, at which time ice layers grow on them. Finally, the drops become so heavy that they fall to the ground like hail. Sometimes hailstones reach the size of a chicken egg.

IN summer time in clear weather, the earth's surface cools. It cools the surface layers of air. Water vapor begins to condense on cold objects - leaves, grass, stones. This is how dew forms. If the surface temperature was negative, then the water droplets freeze, forming frost. Dew usually falls in summer, frost in spring and autumn. At the same time, both dew and frost can form only in clear weather. If the sky is covered with clouds, then the earth's surface cools slightly and cannot cool the air.

According to the method of formation, convective, frontal and orographic precipitation are distinguished. The general condition for the formation of precipitation is the upward movement of air and its cooling. In the first case, the reason for the rise of air is its heating from warm surface(convection). Such precipitation falls all year round in the hot zone and in summer in temperate latitudes. If warm air rises when it interacts with colder air, then frontal precipitation is formed. They are more characteristic of temperate and cold zones, where warm and cold air masses are more common. The reason for the rise of warm air may be its collision with the mountains. In this case, orographic precipitation is formed. They are characteristic of the windward slopes of mountains, and the amount of precipitation on the slopes is greater than on the adjacent parts of the plains.

The amount of precipitation is measured in millimeters. On average, about 1100 mm of precipitation falls on the earth's surface per year.

Distribution of precipitation on the globe. Atmospheric precipitation on the planet is unevenly distributed. It depends on the geographical location of the area and the prevailing winds. The largest number precipitation falls in equatorial (over 2,000 mm) and temperate (over 800 mm) latitudes. Little precipitation (200 mm) falls in tropical and polar latitudes. However, this distribution is disturbed by the nature of the earth's surface: more precipitation falls over the oceans than over land. In the mountains, much more precipitation "accepts" those slopes facing prevailing winds. So, in Ukraine, the windward slopes of the Carpathians receive 1500 mm per year, and the leeward slopes - half as much as -750 mm per year.

I have a record high annual rainfall on Earth in the village of Cherrapunji, at the foot of the Himalayas - 23,000 mm. And the rainiest place on the planet is the Hawaiian Islands, where 335 days a year it happens with rain, which brings 12,000 mm of water. The record dry places where precipitation does not fall for years are the Atacama desert in South America (1 mm per year) and the Sahara in Africa (5 mm per year).

The distribution of precipitation on Earth depends on a number of reasons:

a) from the placement of high and low pressure belts. At the equator and in temperate latitudes, where areas of low pressure are formed, there is a lot of precipitation. In these areas, the air heated from the Earth becomes light and rises, where it meets the colder layers of the atmosphere, cools, and the water vapor turns into water droplets and falls to the Earth in the form of precipitation. In the tropics (30th latitudes) and polar latitudes, where areas high pressure, descending air currents predominate. Cold air descending from upper layers troposphere contains little moisture. When lowered, it shrinks, heats up and becomes even drier. Therefore, in the areas high blood pressure little precipitation falls over the tropics and near the poles;

b) the distribution of precipitation also depends on the geographical latitude. There is a lot of precipitation at the equator and in temperate latitudes. However, the earth's surface at the equator warms up more than at temperate latitudes, so the updrafts at the equator are much more powerful than at temperate latitudes, and therefore, stronger and more abundant precipitation;

c) the distribution of precipitation depends on the position of the terrain relative to the World Ocean, since it is from there that the main share of water vapor comes. For example, less precipitation falls in Eastern Siberia than in the East European Plain, since Eastern Siberia removed from the oceans;

d) the distribution of precipitation depends on the proximity of the area to ocean currents: warm currents contribute to precipitation on the coasts, and cold ones hinder. Cold currents pass along the western coasts of South America, Africa and Australia, which led to the formation of deserts on the coasts; e) the distribution of precipitation also depends on the relief. On the slopes mountain ranges facing moist winds from the ocean, noticeably more moisture falls than on the opposite ones - this is clearly seen in the Cordillera of America, on the eastern slopes of the mountains Far East, on the southern spurs of the Himalayas. Mountains prevent the movement of moist air masses, and the plain contributes to this.

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Thermal belts of the planet. Thermal belt. Cold climate zone

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Thermal belts

What are thermal belts?

Cold climate zone

Temperate zone

hot belt

The nature of the cold thermal zone

The nature of the temperate thermal zone

The nature of the hot thermal zone

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