Tropical and subtropical zones - winds, precipitation, temperature. Climatic conditions in the tropics What is the rainfall regime in the tropical zone

Equatorial climate zone

occupies the area of ​​the Congo River basin and the coast of the Gulf of Guinea in Africa, the Amazon River basin in South America, the Sunda Islands off the coast of Southeast Asia. The gap in the climatic zone on the eastern shores of the continents is explained by the dominance of subtropical baric maxima over the oceans. The greatest flow of air goes along the equatorial periphery of baric maxima; it captures the eastern coasts of the continents. In the equatorial belt, humidification of the tropical air brought by the trade winds takes place. Equatorial air is formed at reduced pressure, light winds and high temperatures. The total radiation value of 580-670 kJ/cm 2 per year is slightly reduced due to the high cloudiness and humidity of the equatorial latitudes. The radiation balance on the mainland is 330 kJ/cm2 per year, on the ocean it is 420-500 kJ/cm2 per year.

At the equator, equatorial VMs dominate throughout the year. The average air temperature ranges from +25 to +28 ○ C, high relative humidity, 70-90%, remains. In equatorial latitudes, on both sides of the equator, an intratropical convergence zone is distinguished, which is characterized by the convergence of the trade winds of the two hemispheres, which causes powerful ascending air currents. But convection develops not only for this reason. The heated air, saturated with water vapor, rises, condenses, forms cumulonimbus clouds, from which showers fall in the afternoon. In this belt, the annual rainfall exceeds 2000 mm. There are places where the amount of precipitation increases up to 5000 mm. High temperatures throughout the year and a large amount of precipitation create conditions for the development of rich vegetation on land - humid equatorial forests - giley (in South America, wet forests are called selva, in Africa - jungle).

Continental and oceanic types of equatorial climate differ slightly.

The climate of the subequatorial zone

confined to the vast expanses of the Brazilian Highlands, Central Africa (to the north, east and south of the Congo Basin), Asia (on the Hindustan and Indochina peninsulas), Northern Australia.

The total solar radiation is about 750 kJ/cm 2 per year, the radiation balance is 290 kJ/cm 2 per year on land and up to 500 kJ/cm 2 per year on the ocean.

The subequatorial climatic zone is characterized by monsoonal air circulation: air moves from the tropical latitudes of the winter hemisphere as a winter dry monsoon (trade wind), after crossing the equator it transforms into a summer wet monsoon. A characteristic feature of this belt is the change of air masses by season: equatorial air dominates in summer, tropical air dominates in winter. There are two seasons - wet (summer) and dry (winter). In the summer season, the climate differs slightly from the equatorial one: high humidity, abundant precipitation caused by ascending currents of equatorial air. The total amount of precipitation is 1500 mm; on the windward slopes of the mountains, their amount increases sharply (Cherrapunji - 12,660 mm). In the winter season, conditions change dramatically with the advent of dry tropical air: hot, dry weather sets in, grasses burn out, trees shed their leaves. Inside the continents and on their western shores, the vegetation cover of the subequatorial belt is represented by savannahs, and humid equatorial forests dominate on the eastern shores.

Tropical climate zone

in the Southern Hemisphere it spreads in a continuous band, expanding over the oceans. The oceans are dominated throughout the year by constant baric maxima, in which tropical WMs form. In the Northern Hemisphere, the tropical belt is torn over Indo-China and Hindustan; The break in the belt is explained by the fact that the dominance of tropical VMs is not observed throughout the year. In summer, equatorial air penetrates into the South Asian Low; in winter, moderate (polar) VMs invade far to the south from the Asian High.

The annual value of total radiation on the continents is 750-849 kJ / cm 2 per year (in the Northern Hemisphere up to 920 kJ / cm 2 per year), on the ocean 670 kJ / cm 2 per year; radiation balance - 250 kJ/cm 2 per year on the mainland and 330-420 kJ/cm 2 per year on the ocean.

In the tropical climate zone, tropical VMs dominate throughout the year, which are characterized by high temperatures. The average temperature of the warmest month exceeds +30 ○ С, on some days the temperature rises to +50 ○ С, and the Earth's surface heats up to +80 ○ С (the maximum temperature of +58 ○ С was recorded on the northern coast of Africa). Due to the increased pressure and downward air currents, there is almost no condensation of water vapor, so there is very little precipitation in most of the tropical belt - less than 250 mm. This causes the formation of the greatest deserts in the world - the Sahara and Kalahari in Africa, the deserts of the Arabian Peninsula, Australia.

The tropical climatic zone covers the globe from the 20th to the 30th parallels in the northern and southern hemispheres. These areas generally have clear weather throughout the year, and the air temperature depends on how high the Sun rises above the horizon. In summer the air warms up to +30°С. Although sometimes it can rise to + 45-50 ° C. In winter, the air is very cold, often to negative readings on the thermometer.

The air temperature can vary greatly during the day, when the sultry heat during the day is replaced by evening coolness and severe cooling at night. In the tropics, little precipitation falls - no more than 50-150 mm per year. Most of them occur during the winter months. These latitudes are very affected by the trade winds.

Types of climate in tropical latitudes

The tropical climate is usually divided into two categories, depending on the proximity of the territory to the ocean.

Continental: In the depths of the continents, the climate in tropical latitudes is hot and arid, with a large temperature difference. This is a region of high atmospheric pressure. The weather is mostly clear and cloudless. And sudden changes in temperature give rise to strong winds and dust storms.

The areas of distribution of the continental tropical climate in the western and eastern regions differ significantly. The western shores of South America, Australia and Africa are washed predominantly by cold currents, therefore, in tropical latitudes, the climate in these areas is cooler, the air rarely warms up by more than 20-25 ° C.

The eastern coasts of the continents are dominated by warm currents, so the temperatures are higher here, and there is more rainfall.

Oceanic: In coastal areas and over the oceans, a milder climate is developing, with an abundance of rainfall, warm summers and mild winters. This type of climate is very similar to the equatorial one, but is characterized by less cloudiness and strong winds. Precipitation falls mainly in the summer months.

Average annual temperatures

The average annual temperatures of the warmest months are 30-35°C, the coldest - at least 10°C. The maximum temperature was recorded at 61°С, the minimum - 0°С and below. The average annual rainfall is between 50 and 200 mm. Only in the eastern oceanic region can fall up to 2000 mm of precipitation per year.

The territory lying in the tropical zone is conditionally divided into four regions:

1. Eastern Oceanic(with high humidity and dominant forests);

2. Eastern Transitional(with a predominance of shrubs and light forests);

3. Inland;

4. Western oceanic(with a predominance of deserts and semi-deserts). The latter region experiences high relative humidity with frequent fogs and relatively stable temperatures.

For areas of the continents located in the tropical zone, a change in natural processes is characteristic when moving from east to west: the runoff layer becomes less abundant (from 100 mm to 2-10 mm) and the water content of rivers decreases (eastern rivers are full-flowing constantly, western - periodically).

To the east, erosion processes and chemical weathering are predominant, to the west and in the inland region - deflation and physical weathering. From east to west, the thickness of the soil cover decreases; for inland and western regions, desert soils with a primitive composition (gypsum, carbonate, solonchaks) are characteristic, which alternate with sands and accumulations of rubble. Also, the types of plant communities change from east to west: mixed evergreen forests are replaced by monsoon deciduous forests and further by savannahs or light forests, dry forests, bush thickets, semi-deserts and deserts. Accordingly, the composition of the fauna is changing - from many forest dwellers to rare inhabitants of desert regions.

From east to west, such zones of the tropical belt on land are distinguished: the zone of tropical moist forests, the zone of light forests, the zone of savannahs and dry forests, tropical semi-deserts and deserts. Mountainous areas are characterized by zones of altitudinal zonation.

Parts of the continents with a tropical climate are poorly developed and inhabited by humans, except for the eastern regions of the continents. In the eastern oceanic region, agriculture and logging are developed, in the western oceanic and inland regions - pasture cattle breeding with areas of irrigated agriculture, as a result of which natural landscapes are almost completely transformed in the process of human economic activity.

In the Köppen climate classification

In the Köppen climate classification, a tropical climate is defined as a non-arid climate in which the average monthly air temperature is above 17 °C. It includes four types of climate, differing in the distribution of precipitation throughout the year.

1. tropical rainy climate - roughly corresponds to Alisov's equatorial climate
2. tropical monsoon rainy climate - roughly corresponds to the subequatorial climate of Alisov
3. tropical climate with dry winters and rainy summers
4. tropical climate with dry summers and rainy winters

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Tropical and subtropical zones are the richest natural zones in terms of the diversity of flora and fauna. The tropical zone is one of the main climatic zones of the planet, and the subtropical zone is one of the transitional ones. They are characterized by a rather hot climate, as they are located near the equator. The formation of the tropics and subtropics occurs under a constant high pressure of the atmosphere, which leads to the establishment of low clouds and the hottest temperatures compared to other belts.

Climate

tropical belt

The tropical belt, according to its climate, divides its natural zones into dry and wet. A distinctive feature of both subzones is considered to be constant strong dry trade winds blowing along the equator.

The dry tropics have a fairly hot dry climate. The average temperature of the warmest months reaches +30 - +35 degrees, and the coldest never drops below +10 degrees. High atmospheric pressure has led to extremely low cloudiness on the territory of this natural zone, little precipitation falls, up to 200 mm per year.

The humid areas of the tropics are characterized by a large amount of precipitation, reaching up to 7000 mm per year. The climate there is as hot as in the dry ones.

subtropical belt

The subtropical zone is located immediately after the tropical. Scientists divide this zone depending on the amount of precipitation into wet and semi-wet. In summer, the average temperature of the subtropical zone reaches 20-25 degrees Celsius, and in winter - not lower than 5 degrees Celsius.

Natural zones of the subtropical belt are found on many continents of our planet. This led to a large number of climate types in this natural zone. Perhaps it is the subtropical belt that can boast of the variety of these conditions. According to the type of climate, the described zone is subdivided:

• Mediterranean climate with abundant winter moisture characteristic of it;
• Continental climate with rather poor moisture;
• Monsoon climate with abundant moisture in summer

natural areas

tropical belt

The tropical belt is habitually divided into the following natural zones, starting from east to west:

• Tropical rainforest zone;
• Light forest zone;
• Zone of dry forests and hot savannas;
• Zone of tropical semi-deserts and deserts.

As a rule, people have sparsely populated all zones, with the exception of some areas of the eastern sections.

subtropical belt

The zones of the tropical belt are more diverse, since their individual sections are found on each continent. On the western part of the ocean coast, they are located in the following order:

• hardwood forests;
• Subtropical steppes;
• Subtropical semi-deserts and deserts;

The southern hemisphere deep on the continent "hides" zones:

• Subtropical steppes;
• To the east - broad-leaved forests of the subtropics;
• In the high regions there are subtropical evergreen forests.

Vegetable world

tropical belt

The tropical zone, due to its favorable location, boasts a rich flora. It is in this natural zone that more than 75% of all representatives of the flora that exist on Earth grow.

marshy forests

In the swamps of the tropical forest, there is a strong depletion of the soil with oxygen, which is why the species composition of plants is scarce here. All representatives of the flora have an external root system that allows them to receive enough oxygen. Usually this type of moist forest is formed in swampy lowlands and is characterized by a low diversity of species.

Mangroves

Mangrove forests grow in coastal areas or in areas with a temperate climate zone, a prerequisite for each is access to warm currents. Here you can see, as if by levels, plants:

• Rhizophores;
• Avicenna;
• Bruggiers and conocarpus;
• Ceriops;
• Aegiceras;
• On the border with the forest - nipa palms.

The crowns of the mangrove forest trees are very dense, so the light through them practically does not pass to the lower tiers. Almost the entire forest litter is occupied by stilted roots, which impede progress.

mountain forests

Such forests grow at an altitude of more than a kilometer. Due to heavy rainfall, fog condenses quite strongly here. The forest is formed by two poorly formed tiers:

• The top one is woody. Represented by tree ferns, magnolias, camellias, giant evergreen oaks, rhododendrons.
• The lower tier is herbal. Represented by mosses and lichens, ferns, undergrowth of trees and herbs.
• There is also extra-tiered vegetation: creepers and epiphytic mosses.

seasonal forests

Seasonal forests receive less rain during certain months. According to the foliage shed in a drought, forests are divided into:

• Evergreen forests (eg eucalyptus);
• Semi-evergreen (the upper tier sheds foliage, while the lower one does not);
• Sparse are represented by one species.

By location in the climate zone:

• Monsoon: laurel, sugar cane, annual grasses, creepers and epiphytes;
• Savannah: palms, bottle trees, cacti, spurges and herbs;
• Prickly xerophilous: legumes (acacia and mimosa), thin lianas and herbaceous cereals;

subtropical belt

Hardwood forests are found in Mediterranean climates, typically represented by:

• On the upper tier: oak, olive tree, cedar and black pine;
• On the second: strawberry, boxwood and phyllyria;
• On the bottom: grasses and mosses.

The monsoon mixed forest is formed by evergreen oak (and other beech), magnolias, pines, laurels, firs, camellias, palms and lianas. Closer to the equator, the species composition is significantly depleted.

Evergreens (hemigiles) differ from their tropical neighbors in a smaller variety of species. The flora is represented by tree ferns, evergreen oaks, camellias and camphor laurel. Among the herbaceous bamboo thickets are found.

Animal world

tropical belt

In terms of the number of living species of animals, tropical forests surpass almost all other natural areas. Animals here usually live in the crowns of tall trees. Among the mammals of the tropical zone there are: Flying squirrels, Hippos, Elephants, Rhinos, Palm squirrels, Many species of monkeys (spider monkey, howler monkey, marmosets), Sloths, Tapir, Tree porcupines,
Spiny-tailed squirrels, Leopards, Tiger, Hedgehogs, Okapi, Lemur lory.

Among amphibians there is a huge variety of frogs (bright climbers), pipa toads, worms and tree frogs.

subtropical belt

The fauna of the subtropical zone is represented by species of the tropics and the temperate zone. To the previous animals are added: mouflon, red deer, fallow deer, ferret, fox, jackal, otter, chaffinch, goldfinch and blackbird.

The subtropical and tropical zones are rich in flora and fauna, have a comfortable warm climate.

Climate- this is a long-term weather regime characteristic of a particular area. It manifests itself in a regular change of all types of weather observed in this area.

Climate influences living and non-living nature. In close dependence on the climate are water bodies, soil, vegetation, animals. Individual sectors of the economy, primarily agriculture, are also very dependent on climate.

The climate is formed as a result of the interaction of many factors: the amount of solar radiation entering the earth's surface; atmospheric circulation; the nature of the underlying surface. At the same time, climate-forming factors themselves depend on the geographical conditions of a given area, primarily on geographical latitude.

The geographic latitude of the area determines the angle of incidence of the sun's rays, the receipt of a certain amount of heat. However, obtaining heat from the Sun also depends on the proximity of the ocean. In places far from the oceans, there is little precipitation, and the mode of precipitation is uneven (in the warm period more than in the cold), cloudiness is low, winters are cold, summers are warm, and the annual temperature amplitude is large. Such a climate is called continental, as it is typical of places located in the depths of continents. Above the water surface, a maritime climate is formed, which is characterized by: a smooth course of air temperature, with small daily and annual temperature amplitudes, high cloudiness, a uniform and fairly large amount of precipitation.

The climate is greatly influenced by sea ​​currents. Warm currents warm the atmosphere in the areas where they flow. For example, the warm North Atlantic current creates favorable conditions for the growth of forests in the southern part of the Scandinavian Peninsula, while most of the island of Greenland, which lies approximately at the same latitudes as the Scandinavian Peninsula, but is outside the zone of influence of the warm current, all year round covered with a thick layer of ice.

plays an important role in shaping the climate relief. You already know that with the rise of the terrain for each kilometer, the air temperature drops by 5-6 ° C. Therefore, on the alpine slopes of the Pamirs, the average annual temperature is 1 ° C, although it is located just north of the tropic.

The location of mountain ranges has a great influence on the climate. For example, the Caucasus Mountains hold back moist sea winds, and their windward slopes facing the Black Sea receive significantly more precipitation than their leeward slopes. At the same time, the mountains serve as an obstacle to the cold northern winds.

There is a dependence of climate and prevailing winds. On the territory of the East European Plain, westerly winds coming from the Atlantic Ocean prevail for almost the entire year, so winters in this area are relatively mild.

The regions of the Far East are under the influence of monsoons. In winter, winds constantly blow from the depths of the mainland. They are cold and very dry, so there is little rainfall. In summer, on the contrary, the winds bring a lot of moisture from the Pacific Ocean. In autumn, when the wind from the ocean subsides, the weather is usually sunny and calm. This is the best time of the year in the area.

Climate characteristics are statistical inferences from long-term weather records (in temperate latitudes, 25-50-year series are used; in the tropics, their duration may be shorter), primarily over the following main meteorological elements: atmospheric pressure, wind speed and direction, temperature and air humidity, cloudiness and precipitation. They also take into account the duration of solar radiation, the visibility range, the temperature of the upper layers of soil and water bodies, the evaporation of water from the earth's surface into the atmosphere, the height and condition of the snow cover, various atmospheric phenomena and ground-based hydrometeors (dew, ice, fog, thunderstorms, snowstorms, etc.) . In the XX century. The climatic indicators included characteristics of the elements of the heat balance of the earth's surface, such as total solar radiation, radiation balance, heat exchange between the earth's surface and the atmosphere, and heat consumption for evaporation. Complex indicators are also used, i.e., functions of several elements: various coefficients, factors, indices (for example, continentality, aridity, moisture), etc.

Climatic zones

Long-term average values ​​of meteorological elements (annual, seasonal, monthly, daily, etc.), their sums, frequencies, etc. are called climate standards: the corresponding values ​​for individual days, months, years, etc. are considered as a deviation from these norms.

Climate maps are called climatic(temperature distribution map, pressure distribution map, etc.).

Depending on the temperature conditions, prevailing air masses and winds, climatic zones.

The main climatic zones are:

• equatorial;
• two tropical;
• two moderate;
• arctic and antarctic.

Between the main belts there are transitional climatic zones: subequatorial, subtropical, subarctic, subantarctic. In transitional zones, air masses change with the seasons. They come here from neighboring zones, so the climate of the subequatorial zone in summer is similar to the climate of the equatorial zone, and in winter - to the tropical climate; the climate of the subtropical zones in summer is similar to the climate of the tropical, and in winter - with the climate of the temperate zones. This is due to the seasonal movement of atmospheric pressure belts over the globe following the Sun: in summer - to the north, in winter - to the south.

Climatic zones are divided into climatic regions. So, for example, in the tropical zone of Africa, areas of tropical dry and tropical humid climates are distinguished, and in Eurasia, the subtropical zone is divided into areas of the Mediterranean, continental and monsoon climate. In mountainous areas, altitudinal zonation is formed due to the fact that air temperature decreases with height.

Diversity of Earth's climates

The classification of climates provides an ordered system for characterizing climate types, their zoning and mapping. Let us give examples of climate types prevailing over vast territories (Table 1).

Arctic and Antarctic climate zones

Antarctic and arctic climate dominates in Greenland and Antarctica, where the average monthly temperatures are below 0 °C. During the dark winter season, these regions receive absolutely no solar radiation, although there are twilight and auroras. Even in summer, the sun's rays fall on the earth's surface at a slight angle, which reduces the heating efficiency. Most of the incoming solar radiation is reflected by the ice. In both summer and winter, low temperatures prevail in the elevated regions of the Antarctic Ice Sheet. The climate of the interior of Antarctica is much colder than the climate of the Arctic, since the southern mainland is large and high, and the Arctic Ocean moderates the climate, despite the wide distribution of pack ice. In summer, during short periods of warming, drift ice sometimes melts. Precipitation on ice sheets falls in the form of snow or small particles of ice mist. Inland regions receive only 50-125 mm of precipitation annually, but more than 500 mm can fall on the coast. Sometimes cyclones bring clouds and snow to these areas. Snowfalls are often accompanied by strong winds that carry significant masses of snow, blowing it off the slope. Strong katabatic winds with snowstorms blow from the cold glacial sheet, bringing snow to the coast.

Table 1. Climates of the Earth

Climate type	Climate zone	Average temperature, °С		Mode and amount of atmospheric precipitation, mm	Atmospheric circulation	Territory
Equatorial	Equatorial			During a year. 2000	Warm and humid equatorial air masses form in the area of ​​low atmospheric pressure.	Equatorial regions of Africa, South America and Oceania
tropical monsoon	Subequatorial			Mostly during the summer monsoon, 2000		South and Southeast Asia, West and Central Africa, Northern Australia
tropical dry	Tropical			During the year, 200		North Africa, Central Australia
Mediterranean	Subtropical			Mainly in winter, 500	In summer - anticyclones at high atmospheric pressure; winter - cyclonic activity	Mediterranean, Southern coast of Crimea, South Africa, Southwestern Australia, Western California
subtropical dry	Subtropical			During a year. 120	Dry continental air masses	Inland parts of the continents
temperate maritime	Moderate			During a year. 1000	westerly winds	Western parts of Eurasia and North America
temperate continental	Moderate			During a year. 400	westerly winds	Inland parts of the continents
moderate monsoon	Moderate			Mostly during the summer monsoon, 560		Eastern margin of Eurasia
Subarctic	Subarctic			During the year, 200	Cyclones prevail	Northern margins of Eurasia and North America
Arctic (Antarctic)	Arctic (Antarctic)			During the year, 100	Anticyclones predominate	The water area of ​​the Arctic Ocean and mainland Australia

subarctic continental climate is formed in the north of the continents (see the climate map of the atlas). In winter, arctic air prevails here, which is formed in areas of high pressure. In the eastern regions of Canada, Arctic air is distributed from the Arctic.

Continental subarctic climate in Asia, it is characterized by the largest annual amplitude of air temperature on the globe (60-65 ° С). The continentality of the climate here reaches its limit.

The average temperature in January varies across the territory from -28 to -50 °C, and in lowlands and hollows, due to air stagnation, its temperature is even lower. In Oymyakon (Yakutia), a record negative air temperature for the Northern Hemisphere (-71 °C) was registered. The air is very dry.

Summer in subarctic belt although short, but quite warm. The average monthly temperature in July ranges from 12 to 18 °C (daily maximum is 20-25 °C). Over the summer, more than half of the annual amount of precipitation falls, amounting to 200-300 mm on the flat territory, and up to 500 mm per year on the windward slopes of the hills.

The climate of the subarctic zone of North America is less continental than the corresponding climate of Asia. It has less cold winters and colder summers.

temperate climate zone

The temperate climate of the western coasts of the continents has pronounced features of the maritime climate and is characterized by the predominance of sea air masses throughout the year. It is observed on the Atlantic coast of Europe and the Pacific coast of North America. The Cordilleras are a natural boundary separating the coast with a maritime type of climate from the inland regions. The European coast, except for Scandinavia, is open to the free access of temperate maritime air.

The constant transfer of sea air is accompanied by high cloudiness and causes protracted springs, in contrast to the interior of the continental regions of Eurasia.

winter in temperate zone warm on the western coasts. The warming effect of the oceans is enhanced by warm sea currents washing the western shores of the continents. The average temperature in January is positive and varies across the territory from north to south from 0 to 6 °C. Intrusions of arctic air can lower it (on the Scandinavian coast down to -25°C, and on the French coast down to -17°C). With the spread of tropical air to the north, the temperature rises sharply (for example, it often reaches 10 ° C). In winter, on the western coast of Scandinavia, there are large positive temperature deviations from the average latitude (by 20 ° C). The temperature anomaly on the Pacific coast of North America is smaller and does not exceed 12 °С.

Summer is rarely hot. The average temperature in July is 15-16°C.

Even during the day, the air temperature rarely exceeds 30 °C. Cloudy and rainy weather is typical for all seasons due to frequent cyclones. There are especially many cloudy days on the western coast of North America, where cyclones are forced to slow down in front of the Cordillera mountain systems. In connection with this, the weather regime in the south of Alaska is characterized by great uniformity, where there are no seasons in our understanding. Eternal autumn reigns there, and only plants remind of the onset of winter or summer. Annual rainfall ranges from 600 to 1000 mm, and on the slopes of mountain ranges - from 2000 to 6000 mm.

In conditions of sufficient moisture, broad-leaved forests are developed on the coasts, and in conditions of excessive moisture, coniferous forests. The lack of summer heat reduces the upper limit of the forest in the mountains to 500-700 m above sea level.

The temperate climate of the eastern coasts of the continents It has monsoonal features and is accompanied by a seasonal change of winds: in winter, northwestern flows predominate, in summer - southeast. It is well expressed on the eastern coast of Eurasia.

In winter, with a northwest wind, cold continental temperate air spreads to the coast of the mainland, which is the reason for the low average temperature of the winter months (from -20 to -25 ° C). Clear, dry, windy weather prevails. In the southern regions of the coast, there is little rainfall. The north of the Amur region, Sakhalin and Kamchatka often fall under the influence of cyclones moving over the Pacific Ocean. Therefore, in winter there is a thick snow cover, especially in Kamchatka, where its maximum height reaches 2 m.

In summer, with a southeasterly wind, temperate sea air spreads on the coast of Eurasia. Summers are warm, with an average July temperature of 14 to 18 °C. Precipitation is frequent due to cyclonic activity. Their annual amount is 600-1000 mm, and most of it falls in the summer. Fog is frequent at this time of the year.

Unlike Eurasia, the eastern coast of North America is characterized by maritime climate features, which are expressed in the predominance of winter precipitation and the marine type of annual air temperature variation: the minimum occurs in February, and the maximum occurs in August, when the ocean is at its warmest.

The Canadian anticyclone, unlike the Asian one, is unstable. It forms far from the coast and is often interrupted by cyclones. Winter here is mild, snowy, wet and windy. In snowy winters, the height of snowdrifts reaches 2.5 m. With a southerly wind, icy conditions often occur. Therefore, some streets in some cities in eastern Canada have iron railings for pedestrians. Summers are cool and rainy. The annual rainfall is 1000 mm.

temperate continental climate it is most clearly expressed on the Eurasian continent, especially in the regions of Siberia, Transbaikalia, northern Mongolia, and also on the territory of the Great Plains in North America.

A feature of the temperate continental climate is the large annual amplitude of air temperature, which can reach 50-60 °C. In the winter months, with a negative radiation balance, the earth's surface cools down. The cooling effect of the land surface on the surface layers of air is especially great in Asia, where a powerful Asian anticyclone forms in winter and cloudy, calm weather prevails. The temperate continental air formed in the area of ​​the anticyclone has a low temperature (-0°...-40°C). In valleys and basins, due to radiation cooling, the air temperature can drop to -60 °C.

In the middle of winter, the continental air in the lower layers becomes even colder than the Arctic. This very cold air of the Asian anticyclone spreads to Western Siberia, Kazakhstan, southeastern regions of Europe.

The winter Canadian anticyclone is less stable than the Asian anticyclone due to the smaller size of the North American continent. Winters here are less severe, and their severity does not increase towards the center of the mainland, as in Asia, but, on the contrary, decreases somewhat due to the frequent passage of cyclones. Continental temperate air in North America is warmer than continental temperate air in Asia.

The formation of a continental temperate climate is significantly influenced by the geographical features of the territory of the continents. In North America, the Cordillera mountain ranges are a natural boundary separating the coast with a maritime climate from the inland regions with a continental climate. In Eurasia, a temperate continental climate is formed over a vast expanse of land, approximately from 20 to 120 ° E. e. Unlike North America, Europe is open to free penetration of sea air from the Atlantic deep into the interior. This is facilitated not only by the western transport of air masses, which prevails in temperate latitudes, but also by the flat nature of the relief, the strong indentation of the coasts and the deep penetration into the land of the Baltic and North Seas. Therefore, a temperate climate of a lesser degree of continentality is formed over Europe compared to Asia.

In winter, the Atlantic sea air moving over the cold land surface of the temperate latitudes of Europe retains its physical properties for a long time, and its influence extends to the whole of Europe. In winter, as the Atlantic influence weakens, the air temperature decreases from west to east. In Berlin it is 0 °С in January, -3 °С in Warsaw, -11 °С in Moscow. At the same time, the isotherms over Europe have a meridional orientation.

The orientation of Eurasia and North America with a wide front to the Arctic Basin contributes to the deep penetration of cold air masses onto the continents throughout the year. Intensive meridional transport of air masses is especially characteristic of North America, where arctic and tropical air often replace each other.

Tropical air entering the plains of North America with southern cyclones is also slowly transformed due to its high speed of movement, high moisture content and continuous low cloudiness.

In winter, the result of intense meridional circulation of air masses are the so-called "jumps" of temperatures, their large daily amplitude, especially in areas where cyclones are frequent: in the north of Europe and Western Siberia, the Great Plains of North America.

In the cold period, they fall in the form of snow, a snow cover forms, which protects the soil from deep freezing and creates a supply of moisture in the spring. The height of the snow cover depends on the duration of its occurrence and the amount of precipitation. In Europe, a stable snow cover on the flat territory is formed east of Warsaw, its maximum height reaches 90 cm in the northeastern regions of Europe and Western Siberia. In the center of the Russian Plain, the height of the snow cover is 30–35 cm, and in Transbaikalia it is less than 20 cm. On the plains of Mongolia, in the center of the anticyclonic region, snow cover forms only in some years. The absence of snow, along with the low winter air temperature, causes the presence of permafrost, which is no longer observed anywhere on the globe under these latitudes.

In North America, the Great Plains have little snow cover. To the east of the plains, tropical air begins to take part in the frontal processes more and more, it intensifies the frontal processes, which causes heavy snowfalls. In the Montreal area, the snow cover lasts up to four months, and its height reaches 90 cm.

Summer in the continental regions of Eurasia is warm. The average July temperature is 18-22°C. In arid regions of southeastern Europe and Central Asia, the average air temperature in July reaches 24-28 °C.

In North America, continental air is somewhat colder in summer than in Asia and Europe. This is due to the smaller extent of the mainland in latitude, the large indentation of its northern part with bays and fjords, the abundance of large lakes, and the more intense development of cyclonic activity compared to the inland regions of Eurasia.

In the temperate zone, the annual amount of precipitation on the flat territory of the continents varies from 300 to 800 mm; on the windward slopes of the Alps, more than 2000 mm falls. Most of the precipitation falls in the summer, which is primarily due to an increase in the moisture content of the air. In Eurasia, there is a decrease in precipitation across the territory from west to east. In addition, the amount of precipitation also decreases from north to south due to a decrease in the frequency of cyclones and an increase in air dryness in this direction. In North America, a decrease in precipitation across the territory is noted, on the contrary, in the direction to the west. Why do you think?

Most of the land in the continental temperate zone is occupied by mountain systems. These are the Alps, the Carpathians, the Altai, the Sayans, the Cordillera, the Rocky Mountains, and others. In the mountainous regions, the climatic conditions differ significantly from the climate of the plains. In summer, the air temperature in the mountains drops rapidly with altitude. In winter, when cold air masses invade, the air temperature in the plains often turns out to be lower than in the mountains.

The influence of mountains on precipitation is great. Precipitation increases on the windward slopes and at some distance in front of them, and weakens on the leeward slopes. For example, differences in annual precipitation between the western and eastern slopes of the Ural Mountains in places reach 300 mm. In mountains with height, precipitation increases to a certain critical level. In the Alps, the level of the greatest amount of precipitation occurs at an altitude of about 2000 m, in the Caucasus - 2500 m.

Subtropical climate zone

Continental subtropical climate determined by the seasonal change of temperate and tropical air. The average temperature of the coldest month in Central Asia is below zero in places, in the northeast of China -5...-10°С. The average temperature of the warmest month is in the range of 25-30°C, while daily highs can exceed 40-45°C.

The most strongly continental climate in the air temperature regime is manifested in the southern regions of Mongolia and in the north of China, where the center of the Asian anticyclone is located in the winter season. Here, the annual amplitude of air temperature is 35-40 °C.

Sharply continental climate in the subtropical zone for the high-mountainous regions of the Pamirs and Tibet, whose height is 3.5-4 km. The climate of the Pamirs and Tibet is characterized by cold winters, cool summers and low rainfall.

In North America, a continental arid subtropical climate is formed in closed plateaus and in intermountain basins located between the Coastal and Rocky Ranges. Summers are hot and dry, especially in the south, where the average July temperature is above 30°C. The absolute maximum temperature can reach 50 °C and above. In Death Valley, a temperature of +56.7 °C was recorded!

Humid subtropical climate characteristic of the eastern coasts of the continents north and south of the tropics. The main areas of distribution are the southeastern United States, some southeastern regions of Europe, northern India and Myanmar, eastern China and southern Japan, northeastern Argentina, Uruguay and southern Brazil, the coast of Natal in South Africa and the east coast of Australia. Summer in the humid subtropics is long and hot, with the same temperatures as in the tropics. The average temperature of the warmest month exceeds +27 °С, and the maximum temperature is +38 °С. Winters are mild, with average monthly temperatures above 0°C, but occasional frosts have a detrimental effect on vegetable and citrus plantations. In the humid subtropics, the average annual precipitation ranges from 750 to 2000 mm, the distribution of precipitation over the seasons is quite uniform. In winter, rains and rare snowfalls are brought mainly by cyclones. In summer, precipitation falls mainly in the form of thunderstorms associated with powerful inflows of warm and humid oceanic air, which are characteristic of the monsoonal circulation of East Asia. Hurricanes (or typhoons) appear in late summer and autumn, especially in the Northern Hemisphere.

subtropical climate with dry summers is typical of the western coasts of the continents north and south of the tropics. In Southern Europe and North Africa, such climatic conditions are typical for the Mediterranean coasts, which was the reason to call this climate also mediterranean. A similar climate is in southern California, the central regions of Chile, in the extreme south of Africa and in a number of areas in southern Australia. All these regions have hot summers and mild winters. As in the humid subtropics, there are occasional frosts in winter. In inland areas, summer temperatures are much higher than on the coasts, and often the same as in tropical deserts. In general, clear weather prevails. In summer, on the coasts near which ocean currents pass, there are often fogs. For example, in San Francisco, summers are cool, foggy, and the warmest month is September. The maximum precipitation is associated with the passage of cyclones in winter, when the prevailing air currents mix towards the equator. The influence of anticyclones and downward air currents over the oceans determine the dryness of the summer season. The average annual precipitation in a subtropical climate varies from 380 to 900 mm and reaches maximum values ​​on the coasts and mountain slopes. In the summer, there is usually not enough rainfall for the normal growth of trees, and therefore a specific type of evergreen shrub vegetation develops there, known as maquis, chaparral, mal i, macchia and fynbosh.

Equatorial climate zone

Equatorial type of climate distributed in equatorial latitudes in the Amazon basin in South America and the Congo in Africa, on the Malay Peninsula and on the islands of Southeast Asia. Usually the average annual temperature is about +26 °C. Due to the high noon position of the Sun above the horizon and the same length of the day throughout the year, seasonal temperature fluctuations are small. Humid air, cloudiness and dense vegetation prevent nighttime cooling and maintain maximum daytime temperatures below +37 °C, lower than at higher latitudes. The average annual rainfall in the humid tropics ranges from 1500 to 3000 mm and is usually evenly distributed over the seasons. Precipitation is mainly associated with the intratropical convergence zone, which is located slightly north of the equator. Seasonal shifts of this zone to the north and south in some areas lead to the formation of two precipitation maxima during the year, separated by drier periods. Every day, thousands of thunderstorms roll over the humid tropics. In the intervals between them, the sun shines in full force.

Appeared in the 70s of the XIX century and had a descriptive character. According to the classification of professor of Moscow State University B.P. Alisov, there are 7 types of climates on Earth, which make up climatic zones. 4 of them are main, and 3 are transitional. The main types are:

Equatorial climate zone. This type of climate is characterized by the dominance of the equatorial throughout the year. On the days of the spring (March 21) and autumn (September 21) equinoxes, the Sun is at its zenith and greatly heats the Earth. The air temperature in this climatic zone is constant (+24-28°С). At sea, temperature fluctuations can generally be less than 1°. The annual amount of precipitation is significant (up to 3000 mm), on the windward slopes of the mountains precipitation can fall up to 6000 mm. The amount of precipitation here exceeds evaporation, therefore, in the equatorial climate, they are swampy, and thick and high grow on them. The climate of this zone is also influenced by the trade winds, which bring an abundance of precipitation here. The equatorial type of climate is formed over the northern regions; on the coast of the Gulf of Guinea, above the basin and headwaters, including the shores in Africa; over most of the Indonesian archipelago and adjacent parts and the Pacific Oceans in Asia.
Tropical climate zone. This type of climate forms two tropical climatic zones (in the Northern and Southern Hemisphere) over the following territories.

In this type of climate, the state of the atmosphere over the mainland and the ocean is different, therefore, a continental and oceanic tropical climate is distinguished.

Continental climate zone: a large area is dominated by the region, so there is very little precipitation here (from 100-250 mm). The mainland tropical climate is characterized by very hot summers (+35-40°C). In winter the temperature is much lower (+10-15°С). The daily fluctuations in temperature are great (up to 40 °C). The absence of clouds in the sky leads to the formation of clear and cold nights (clouds could trap the heat coming from the Earth). Sharp daily and seasonal temperature changes contribute, which gives a lot of sand and dust. They are picked up and can be carried over considerable distances. These dusty sandstorms are a great danger to the traveler.

Mainland tropical climates The western and eastern coasts of the continents are very different from each other. Cold currents pass along the western coasts of South America and Africa, so the climate here is characterized by relatively low air temperature (+ 18-20 ° C) and low rainfall (less than 100 mm). Warm currents pass along the eastern coasts of these continents, so the temperatures are higher here and there is more precipitation.

Oceanic tropical climate similar to the equatorial, but differs from it by smaller and more stable winds. Summer over the oceans is not so hot (+20-27°С), and winter is cool (+10-15°С). Precipitation falls mainly in summer (up to 50 mm). Moderate. There is a significant influence of westerly winds, bringing precipitation throughout the year. Summer in this climatic zone is moderately warm (from +10°С to +25-28°С). Winter is cold (from +4°С to -50°С). Annual precipitation is from 1000 mm to 3000 mm along the outskirts of the mainland and up to 100 mm in the interior. There are clear differences between the seasons. This type of climate also forms two belts in the northern and southern hemispheres and is formed over territories (from 40-45 ° north to the polar circles). Above these territories, an area of ​​low pressure and active cyclonic activity is formed. Temperate climates are divided into two subtypes:

1. nautical, which dominates in the western parts of North America, South America, is formed with the direct impact of westerly winds from the ocean to the mainland, therefore it is characterized by cool summers (+ 15-20 ° С) and warm winters (from + 5 ° С). Precipitation brought by western winds falls all year round (from 500 mm to 1000 mm, in the mountains up to 6000 mm);
2. continental, dominating in the central regions of the continents, differs from it. Cyclones penetrate here less often than in coastal areas, so summers are warm here (+ 17-26 ° С), and winters are cold (-10-24 ° С) with a stable multi-month. Due to the considerable length of Eurasia from west to east, the most pronounced continental climate is observed in Yakutia, where average January temperatures can drop to -40 ° C and there is little precipitation. This is because the interior of the mainland is not as influenced by the oceans as the coasts, where moist winds not only bring precipitation, but also moderate the heat in summer and frost in winter.

The monsoon subtype, which dominates in the east of Eurasia to Korea and in the north, in the northeast, is characterized by a change in stable winds (monsoons) by season, which affects the amount and pattern of precipitation. In winter, a cold wind blows from the continent, so the winter is clear and cold (-20-27°C). In summer, winds bring warm, rainy weather. In Kamchatka, 1600 to 2000 mm of precipitation falls.

In all subtypes of the temperate climate, only moderate air masses dominate.

Polar type of climate. Above 70 ° north and 65 ° south latitudes, the polar climate dominates, forming two belts: and. Polar air masses dominate here throughout the year. The sun does not appear at all for several months (polar night) and does not go below the horizon for several months (polar day). Snow and ice radiate more heat than they receive, so the air is very cold and does not melt all year round. Throughout the year, these areas are dominated by a high pressure area, so the winds are weak, there are almost no clouds. There is very little precipitation, the air is saturated with small ice needles. Settling, they give a total of only 100 mm of precipitation per year. The average temperature in summer does not exceed 0°С, and in winter -20-40°С. Long drizzle is typical for summer.

Equatorial, tropical, temperate, polar types of climate are considered the main ones, since within their zones the air masses characteristic of them dominate throughout the year. Between the main climatic zones are transitional, having the prefix "sub" in the name (Latin "under"). In transitional climatic zones, air masses change seasonally. They come here from neighboring belts. This is explained by the fact that as a result of the movement of the Earth around its axis, the climatic zones shift to the north, then to the south.

There are three additional types of climate:

subequatorial climate. In summer, this zone is dominated by equatorial air masses, and in winter - by tropical ones.

Summer: a lot of precipitation (1000-3000 mm), average +30°С. The sun reaches its zenith in spring and scorches mercilessly.

Winter is cooler than summer (+14°C). There is little rainfall. The soils dry out after the summer rains, therefore, in the subequatorial climate, unlike, swamps are rare. The territory is favorable for human settlement, therefore it is here that many centers of the emergence of civilization are located -,. According to N.I. , it is from here that many varieties of cultivated plants originated. The northern subequatorial belt includes: South America (Isthmus of Panama,); Africa (Sahel belt); Asia (India, all of Indochina, South China,). The southern subequatorial belt includes: South America (lowland,); Africa (center and east of the mainland); (northern coast of the mainland).

subtropical climate. Tropical air masses dominate here in summer, while air masses of temperate latitudes, carrying precipitation, invade here in winter. This determines the following weather in these areas: hot, dry summers (from +30 to +50°С) and relatively cold winters with precipitation, stable snow cover is not formed. The annual rainfall is about 500 mm. Inside the continents in subtropical latitudes, there is little precipitation in winter. The climate of dry subtropics dominates here with hot summers (up to +50°C) and unstable winters, when frosts down to -20°C are possible. In these areas, precipitation is 120 mm or less. In the western parts of the continents, it dominates, which is characterized by hot, cloudy summers without precipitation and cool, windy and rainy winters. More precipitation falls in the Mediterranean climate than in the dry subtropics. The annual amount of precipitation here is 450-600 mm. The Mediterranean climate is extremely favorable for human life, which is why the most famous summer resorts are located here. Valuable subtropical crops are grown here: citrus fruits, grapes, olives.

The subtropical climate of the eastern shores of the continents is monsoonal. Winter here is cold and dry compared to other climates, and summer is hot (+25°С) and humid (800 mm). This is due to the influence of the monsoons, which blow from land to sea in winter, and from sea to land in summer, and bring precipitation in summer. The monsoonal subtropical climate is well expressed only in the Northern Hemisphere, especially on the east coast of Asia. Abundant rainfall in the summer makes it possible to develop lush. On fertile soils, it is developed here, supporting the life of more than a billion people.

subpolar climate. In summer, humid air masses come here from temperate latitudes, so the summer is cool (from +5 to +10 ° C) and about 300 mm of precipitation falls (in the northeast of Yakutia 100 mm). As elsewhere, precipitation increases on the windward slopes. Despite the small amount of precipitation, the moisture does not have time to evaporate completely, therefore, in the north of Eurasia and North America, small lakes are scattered in the subpolar zone, and large areas are swamped. In winter, the weather in this climate is influenced by arctic and antarctic air masses, so there are long, cold winters, temperatures can reach as low as -50°C. Subpolar climatic zones are located only on the northern outskirts of Eurasia and North America and in Antarctic waters.