Climatology (from “climate” and “logy”) is a science that studies issues of climate formation, description and classification of the world’s climates, and anthropogenic influences on climate.
Meteorology (from the Greek metéōros, atmospheric and celestial phenomena) is the science of the structure and properties of the earth’s atmosphere and events occurring in it physical processes. A significant part of meteorologists is engaged in modeling weather forecasts, climate, and atmospheric research.
Climate zones of the Earth
In Russia and in the territory former USSR The classification of climate types created in 1956 by the famous Soviet climatologist B.P. Alisov was used. This classification takes into account the characteristics of atmospheric circulation. According to this classification, there are four main climatic zones for each hemisphere of the Earth: equatorial, tropical, temperate and polar (in the northern hemisphere - arctic, in southern hemisphere– Antarctic). Between the main zones there are transitional belts - sub equatorial belt, subtropical, subpolar (subarctic and subantarctic). In these climatic zones, in accordance with the prevailing circulation air masses, four types of climate can be distinguished: continental, oceanic, western climate and eastern coastal climate (see Fig. 1).
Rice. 1. Climatic zones
As can be seen from the analysis of the map, the names of the belts correspond to their geographical location, so it is easy to remember their name.
The main climatic zones correspond to the distribution of four types of air masses (see Table 1).
Table 1. Types of air masses
Equatorial belt
This kind permanent belt is located in the region of the equator. It is considered to be the only belt that is torn into several parts. Throughout the year, it is under the influence of one air mass, which is also called equatorial.
The main characteristics of the belt: heat (temperature from 20°C), large amounts of precipitation - up to 7000 mm per year, high humidity. The natural zone of this belt is rain forests, in which many poisonous animals and plants live.
The equatorial belt includes the Amazon Lowland, which is located in South America, the Greater Sunda Islands and equatorial Africa(see Fig. 2).
Tropical and subtropical zones
The tropical type of climate zone is characteristic of tropical latitudes. In the tropics, the weather will depend on the height of the sun above the horizon. The tropical zone is characterized by sharp changes in temperature - from cold to hot. Tropical zones are dominated by the tropical zone, high pressure, and downward air movement. In summer the air is very hot. In winter the air is cooler. Tropical air masses are dry. Rain is a rare occurrence on the land plains. There are few of them over the ocean.
For this reason it natural area presented in the form of semi-deserts and deserts, plant and animal world of which is very scarce (see Fig. 3). The tropical zone is typical for Mexico, North Africa, the Caribbean islands, southern Brazil and Central Australia.
The subtropical zone is located between the temperate and tropical zones. They separate the southern and northern subtropical zones. In summer, tropical heat reigns here, which is characterized by dryness, and in winter a moderate cold air mass prevails.
The subtropical zone is located in the territory North America(USA), it is characteristic of southern Japan, North Africa and the Great Chinese Plain. And in the southern hemisphere, the subtropical zone is occupied by the north of New Zealand, the south of Australia and the south of Africa.
Temperate zone
The main characteristic of this belt is that the temperature of one air mass varies by season: cold winter, hot summer, spring and autumn can be clearly distinguished. The temperate zone is characterized by negative temperatures. Temperate air and westerly winds prevail in temperate zones. It is much colder here than in the tropics. There is a lot of precipitation, but it is unevenly distributed
The temperate zone is located over a large territory of Europe, the northern USA, Canada, Russia, and Great Britain. He reaches out to Far East and northern Japan.
Arctic and Antarctic climate zones
In the Arctic and Antarctic belts Arctic air predominates throughout the year. Snow and ice surfaces well reflect the sun's rays, which fall here at an angle close to 180°. Therefore, the temperature and humidity here are very low, only in some places in the summer months the thermometer rises to +5°C. In Antarctica, temperatures in winter (in August) sometimes reach -71°C, and in the warmest months they only rise to -20°C. There is little precipitation at the poles.
Bibliography
MainI
1. Geography. Land and people. 7th grade: Textbook for general education. uch. / A.P. Kuznetsov, L.E. Savelyeva, V.P. Dronov, series “Spheres”. – M.: Education, 2011.
2. Geography. Land and people. 7th grade: atlas, “Spheres” series.
Additional
1. N.A. Maksimov. Behind the pages of a geography textbook. – M.: Enlightenment.
1. Russian geographical society ().
3. Tutorial by geography ().
4. Gazetteer ().
Definition 1
Climate zone is a latitudinal strip on the Earth’s surface with a relatively uniform climate.
Climate zones differ from each other air temperature And dominant air masses. In accordance with their properties, the main features of the climate are determined. Climate zones on the planet are changing zonally, i.e. from equator to poles. The classification of climate zones, which is used in Russia and in most countries of the world, was created by a Soviet climatologist B.P. Alisov in $1956$ He highlights basic and transitional climatic zones.
There are seven main climatic zones:
- Equatorial belt;
- Two tropical zones;
- Two temperate zones;
- Two polar belts - Arctic and Antarctic.
In these climatic zones, only air masses with the same names dominate throughout the year.
Equatorial climate zone located on both sides of the equator. The territory and water area of the belt receives a large amount of heat throughout the year, and average monthly temperatures are $24$-$28$ degrees. On land, the radiation balance reaches $90$ kcal/cm2. in year. Annual precipitation is up to $3000$ mm per year, and on the windward slopes - up to $10,000$ mm. There is excessive moisture here because the amount of precipitation is much greater than evaporation.
Tropical climate zones. One tropical zone is located in Northern hemisphere of the planet, the second - in South hemispheres. Tropical zones cross all continents except Antarctica and are well expressed in the oceans between the $20$ and $30$ parallels of both hemispheres. The formation of the tropical climate is influenced by tropical air masses, with their characteristic high atmospheric pressure and anticyclonic circulation. Throughout the year there is very little cloud cover, relative humidity and annual rainfall. The prevailing winds are trade winds. Summer average monthly air temperatures are +$30$-$35$ degrees, winter temperatures are not lower than +$10$ degrees. The daily and annual amplitudes are quite high. Annual precipitation ranges from $50$-$200$ mm. The exception is the eastern outskirts of the continents, and on the islands the windward slopes of the mountains receive up to $2000$ mm or more. For example, about $13,000 mm falls in the Hawaiian Islands. On the western coasts of the continents the climate will be cooler, which is associated with cold ocean currents. There will be higher air humidity, an even temperature change and frequent fogs.
Temperate climate zones. One temperate zone is located in Northern hemisphere, between $40$ and $65$ parallel, the other - in South between $42$ and $58$ parallel. These are the largest climatic zones in terms of area. One of the differences between these belts is that in the Northern Hemisphere the belt occupies more than half sushi, while in the Southern Hemisphere it is the opposite. There $98\%$ comes from ocean. In temperate zones there is a clear seasonality of climate. It is expressed in big difference between summer and winter temperatures. Moreover, in the Northern Hemisphere, the annual and daily amplitude is significantly higher than in the Southern Hemisphere. The western transport of air masses of temperate latitudes dominates here, and intense cyclonic activity is observed. Towards the outskirts of the continents, the amount of precipitation increases, and the annual amount is $800$-$2000$mm. On the windward oceanic slopes their number increases and reaches $5000$-$8000$ mm.
Polar climate zones(Arctic and Antarctic). In the Northern Hemisphere arctic the belt begins north of the $70$ parallel, and Antarctic south of the $65$ parallel. Both zones are characterized by polar nights and polar days. Eternal ice and snow emit enormous amounts of solar heat, causing the air to become very chilled. Atmosphere pressure all year round high and easterly winds prevail. Located in Antarctica pole of cold planets. In summer, the average air temperature is $30$ degrees, and in winter -$70$. At the Russian polar station " East"The temperature drops to -$88.3 degrees. On the Antarctic coast, average monthly summer temperatures range from -$1$ to -$5$ degrees, and winter temperatures from -$18$ to -$20$ degrees. Above the Greenland ice sheet in Arctic climatic conditions similar, but softer. In the Atlantic regions Arctic and to the pole, the summer temperature is about $0$ degrees, and with warm air invasion it rises to +$5$. Average winter temperatures are around -$20$ degrees. American The Arctic sector is more severe with temperatures of -$50$ degrees in winter and -$10$ degrees in summer. Largest quantity precipitation falls on European sector of the Arctic, where $300$-$350$ mm falls, and in Asian and American sector from $160$-$250$ mm.
Transitional climatic zones.
Between the main climatic zones there are zones transition zones. There are $6$ and they are characterized by seasonal changes in the prevailing air masses, i.e. In summer, one air mass dominates there, and in winter, another. The names of all transition zones are appended with the prefix “ sub", which translated from Latin means " under", i.e., a belt located under main.
Transitional belts include:
- Two subequatorial belts;
- Two subtropical zones;
- Subarctic belt;
- Subantarctic belt.
Subequatorial climate zone. These belts are located south and north of the equatorial one. As a result of the shift in climate zones according to the seasons of the year, humid equatorial air comes here in the summer, and dry tropical air comes here in the winter. Summer For subequatorial belts will wet, A winter is dry. Despite this, the average annual precipitation is excessive and reaches $1500$ mm per year. On the slopes of the mountains, precipitation falls even more - $6000$-$10000$ mm per year. The difference between summer and winter temperatures is small, but the difference with the equatorial belt is noticeable. Summer temperatures range from $22$-$30$ degrees. In addition to the oceans, the subequatorial belt passes through South America, Central Africa, Hindustan, Indochina, and Northern Australia.
Subtropical climate zones. They are located within $30$-$40$ degrees of the Northern and Southern Hemispheres. In the south, the subtropics border on the tropical zone, and in the north on the temperate zone in the Northern Hemisphere. In the Southern Hemisphere, there is a tropical zone to the north of the subtropics, and a temperate zone to the south. Thermal regimes alternate by half of the year - in winter there is a moderate regime, and in summer - tropical. For the subtropics, frosts are already possible. Within the ocean, the belts differ high temperature and high salinity of water.
Subarctic climate zone. This transition belt is the closest to North Pole Earth. Temperate and arctic air masses replace each other throughout the year. The belt occupies Northern Canada, Alaska, the southern tip of Greenland, northern Iceland and the Scandinavian Peninsula. Within Russia, it passes through the northern part of Western and Central Siberia, as well as the Far East.
Subantarctic climate zone. Located in the Southern Hemisphere, this belt occupies a number of Antarctic islands and the northern tip of the Antarctic Peninsula. The belt is characterized by short summers with temperatures below + $20$ degrees. Cold air masses in winter reduce temperatures to negative values. And it stays below zero for most of the year. The same is typical for the subarctic zone. There is little precipitation and it decreases from $500$-$250$ mm and below.
Climate-forming factors
The formation of the planet's climate is greatly influenced by external and internal factors. Most external factors influence the total amount of incoming solar radiation and its distribution across seasons, hemispheres and continents.
External factors include the parameters of the earth’s orbit and the earth’s axis:
- Distance between the Sun and Earth. It determines the amount of solar energy received;
- The inclination of the rotation of the earth's axis to the orbital plane, which determines seasonal changes;
- Earth's orbital eccentricity. Affects heat distribution and seasonal changes.
Internal factors include:
- Configuration of oceans and continents and their relative positions;
- The presence of active volcanoes that can change the climate until a volcanic winter;
- Albedo of the Earth's atmosphere and its surface;
- Air masses;
- The proximity of oceans and seas that moderate the climate, with the exception of cold currents;
- The nature of the underlying surface;
- Human economic activity;
- Heat flows of the planet.
The air temperature here is constant (+24° -26°C); at sea, temperature fluctuations can be less than 1°. The annual amount of precipitation is up to 3000 mm, and in the mountains of the equatorial belt, precipitation can fall up to 6000 mm. More water falls from the sky than evaporates, so there are many wetlands and dense rain forests - jungles. Remember the adventure films about Indiana Jones - how difficult it is for the main characters to make their way through the dense vegetation of the jungle and escape from the crocodiles who adore muddy waters small forest streams. All this is the equatorial belt. Its climate is greatly influenced by the trade winds, which bring heavy rainfall from the ocean.
Northern: Africa (Sahara), Asia (Arabia, southern Iranian Plateau), North America (Mexico, Western Cuba).
Southern: South America(Peru, Bolivia, Northern Chile, Paraguay), Africa (Angola, Kalahari Desert), Australia ( central part mainland).
In the tropics, the state of the atmosphere over the continent (earth) and the ocean is different, therefore continental tropical climate and oceanic tropical climate.
The oceanic climate is similar to the equatorial climate, but differs from it in less cloudiness and stable winds. Summers over the oceans are warm (+20-27°C), and winters are cool (+10-15°C).
Over the land-tropics (mainland tropical climate) region is dominated by high pressure, so rain is a rare guest here (from 100 to 250 mm). This type of climate is characterized by very hot summers (up to +40°C) and cool winters (+15°C). The air temperature can change dramatically during the day - up to 40°C! That is, a person can languish from the heat during the day and shiver from the cold at night. Such changes lead to the destruction of rocks, creating a mass of sand and dust, which is why dust storms are frequent here.
Photo: Shutterstock.com
This type of climate, like the tropical one, forms two zones in the Northern and Southern Hemispheres, which form over areas of temperate latitudes (from 40-45° North and South latitudes to the Arctic Circles).
There are many cyclones in the temperate zone, causing the weather to become capricious and produce either snow or rain. In addition, westerly winds blow here, which bring precipitation all year round. Summers in this climate zone are warm (up to +25°-28°C), winters are cold (from +4°C to -50°C). Annual precipitation ranges from 1000 mm to 3000 mm, and in the center of the continents it is only up to 100 mm.
In the temperate climate zone, unlike the equatorial and tropical ones, the seasons are clearly defined (that is, you can build snowmen in winter and swim in a river in summer).
Temperate climate is also divided into two subtypes - marine and continental.
Marine dominates the western parts of North America, South America and Eurasia. It is formed by westerly winds blowing from the ocean to the mainland, so there is quite cool summer(+15 -20°С) and warm winter(from +5°C). Precipitation brought by westerly winds falls all year round (from 500 to 1000 mm, in the mountains up to 6000 mm).
Continental predominates in central regions continents. Cyclones penetrate here less frequently, so there are warmer and drier summers (up to +26°C) and colder winters (up to -24°C), and the snow lasts a very long time and melts reluctantly.
Photo: Shutterstock.com
Polar belt
It dominates the territory above 65°-70° latitude in the Northern and Southern Hemispheres, therefore it forms two zones: Arctic and Antarctic. The Polar Belt has a unique feature - the Sun does not appear here at all for several months (polar night) and does not go below the horizon for several months (polar day). Snow and ice reflect more heat than they receive, so the air is very cool and the snow does not melt for most of the year. Since a high pressure area is forming here, there are almost no clouds, the winds are weak, and the air is saturated with small ice needles. The average summer temperature does not exceed 0°C, and in winter it ranges from -20° to -40°C. Rain falls only in the summer in the form of tiny droplets - drizzle.
Between the main climatic zones there are transitional zones, which have the prefix “sub” in their names (translated from Latin as “under”). Here, air masses change seasonally, coming from neighboring belts under the influence of the Earth's rotation.
a) Subequatorial climate. In summer, all climatic zones shift to the north, so equatorial air masses begin to dominate here. They shape the weather: a lot of precipitation (1000-3000 mm), average air temperature +30°C. Even in the spring the sun reaches its zenith and burns mercilessly. In winter, all climatic zones shift to the south, and tropical air masses begin to dominate in the subequatorial zone; winter is cooler than summer (+14°C). There is little precipitation. The soils dry out after summer rains, so in the subequatorial zone, unlike the equatorial zone, there are few swamps. The territory of this climatic zone is favorable for human life, which is why many centers of civilization are located here.
The subequatorial climate forms two zones. The northern ones include: the Isthmus of Panama ( Latin America), Venezuela, Guinea, the Sahel desert belt in Africa, India, Bangladesh, Myanmar, all of Indochina, Southern China, part of Asia. The southern zone includes: the Amazonian lowland, Brazil (South America), central and eastern Africa and the northern coast of Australia.
b) Subtropical climate. Here tropical air masses predominate in summer, and in winter - air masses of temperate latitudes, which determines the weather: hot, dry summers (from +30°C to +50°C) and relatively cold winters with precipitation, and no stable snow cover is formed.
c) Subpolar climate. This climate zone is located only on the northern edges of Eurasia and North America. In summer, humid air masses come here from temperate latitudes, so summers here are cool (from +5°C to +10°C) Despite the small amount of precipitation, evaporation is low, since the angle of incidence sun rays is small and the earth does not warm up well. Therefore, in the subpolar climate in northern Eurasia and North America there are many lakes and swamps. In winter, cold arctic air masses come here, so winters are long and cold, temperatures can drop to -50°C.
They appeared back in the 70s of the 19th century and were of a descriptive nature. According to the classification of Moscow State University professor B.P. Alisov, there are 7 types of climates on Earth, which make up climatic zones. 4 of them are basic, and 3 are transitional. The main types include:
Equatorial climate zone. This type of climate is characterized by the dominance of equatorial climates throughout the year. On the days of the spring (March 21) and autumn (September 21) equinox, the Sun is at its zenith and greatly heats the Earth. The air temperature in this climate zone is constant (+24-28°C). 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, so in the equatorial climate they are swampy, and dense and tall trees grow on them. On climate this belt The trade winds also have an influence, bringing an abundance of precipitation here. The equatorial climate type is formed over the northern regions; on the coast of the Gulf of Guinea, over the basin and headwaters, including the coast 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 climate zones (in the Northern and Southern Hemisphere) over the following areas.
In this type of climate, the state of the atmosphere over the continent and the ocean is different, therefore a distinction is made between continental and oceanic tropical climates.
Continental climate zone: the region dominates over a significant territory, so very little precipitation falls 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°C). There are large daily temperature fluctuations (up to 40 °C). The absence of clouds in the sky leads to the formation of clear and cold nights (clouds could trap heat coming from the Earth). Sharp daily and seasonal temperature changes contribute, which produces a lot of sand and dust. They are picked up and can be carried over considerable distances. These dusty sandstorms are a great danger for a traveler in.
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 temperatures (+18-20°C) and low precipitation (less than 100 mm). Warm currents pass along the eastern coasts of these continents, so temperatures here are higher and there is more precipitation.
Oceanic tropical climate similar to the equatorial one, but differs from it in smaller and more stable winds. Summer over the oceans is not so hot (+20-27°C), and winter is cool (+10-15°C). 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 climate zone is moderately warm (from +10°C to +25-28°C). Winter is cold (from +4°С to -50°С). Annual precipitation ranges from 1000 mm to 3000 mm on the outskirts of the continent and up to 100 mm in the interior. The differences between the seasons of the year are clearly visible. This type of climate also forms two zones in the Northern and Southern Hemispheres and is formed over the territories (from 40-45° northern to the polar circles). A region is formed above these territories low pressure, active cyclonic activity. Temperate climates are divided into two subtypes:
- nautical, which dominates in the western parts of North America and South America, is formed under the direct influence of westerly winds from the ocean to the mainland, therefore it is characterized by cool summers (+15-20°C) and warm winters (from +5°C). Precipitation brought by westerly winds falls all year round (from 500 mm to 1000 mm, in the mountains up to 6000 mm);
- continental, dominant in the central regions of the continents, differs from it. Cyclones penetrate here less often than in coastal areas, so summers here are warm (+17-26°C), and winters are cold (-10-24°C) with stable multi-month temperatures. Due to the significant extent 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 happens because the interior of the continent is not exposed to the same influence of the oceans as the coasts, where moist winds not only bring precipitation, but also mitigate the heat in summer and frost in winter.
The monsoon subtype, dominant in the east of Eurasia to Korea and in the north, in the northeast, is characterized by a change in stable winds (monsoons) over the seasons, which affects the amount and regime of precipitation. It blows here in winter cold wind from the continent, so winter is clear and cold (-20-27°C). In summer, winds bring warm, rainy weather. In Kamchatka, precipitation falls from 1600 to 2000 mm.
In all subtypes of temperate climates, only moderate air masses dominate.
Polar climate type. Above 70° north and 65° south latitudes, a polar climate prevails, forming two zones: and. Polar air masses prevail here all year round. 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 emit more heat than they receive, so the air is very cool and does not melt all year round. Throughout the year, a high pressure area dominates over these areas, so the winds are weak and there are almost no clouds. There is very little precipitation, the air is saturated with small ice needles. As they settle, they provide a total of only 100 mm of precipitation per year. The average summer temperature does not exceed 0°C, and winter -20-40°C. Long drizzle is typical for summer.
Equatorial, tropical, temperate, polar climate types are considered the main ones, since within their zones the air masses characteristic of them dominate throughout the year. Between the main climatic zones there are transitional ones, which have the prefix “sub” (Latin for “under”) in their names. In transitional climate 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, climatic zones shift either to the north or to the south.
There are three additional climate types:
Subequatorial climate. In summer, this belt is dominated by equatorial air masses, and in winter by tropical ones.
Summer: a lot of precipitation (1000-3000 mm), average +30°C. Even in the spring the sun reaches its zenith and burns mercilessly.
Winter is cooler than summer (+14°C). There is little precipitation. The soils dry out after the summer rains, so in the subequatorial climate, unlike in the subequatorial climate, swamps are rare. The territory is favorable for human settlement, which is why many centers of civilization are located here -,. According to N.I. , this is where many varieties originated cultivated plants. The northern subequatorial belt includes: South America (Isthmus of Panama); Africa (Sahel belt); Asia (India, all of Indochina, Southern China, ). The southern subequatorial belt includes: South America (lowland); Africa (centre and east of the continent); (northern coast of the mainland).
Subtropical climate. Here in summer tropical air masses dominate, and in winter air masses of temperate latitudes invade here, carrying precipitation. This determines the following weather in these areas: hot, dry summers (from +30 to +50°C) and relatively cold winters with precipitation, no stable snow cover is formed. Annual precipitation is about 500 mm. Inside the continents in subtropical latitudes there is little precipitation even in winter. The climate here is dominated by dry subtropics with hot summers (up to +50°C) and unstable winters, when frosts down to -20°C are possible. Precipitation in these areas is 120 mm or less. In the western parts of the continents it dominates, which is characterized by hot, partly cloudy summers without precipitation and cool, windy and rainy winters. The Mediterranean climate receives more precipitation than the dry subtropics. The annual 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 coasts of the continents is monsoon. Winter here, compared to other climates, is cold and dry, and summer is hot (+25°C) and humid (800 mm). This is explained by the influence of the monsoons, which blow from land to sea in winter, and from sea to land in summer, bringing precipitation in summer. The monsoon subtropical climate is well defined only in the Northern Hemisphere, especially on the east coast of Asia. Heavy rainfall in summer time give the opportunity to develop magnificently. The fertile soils here support the life of more than a billion people.
Subpolar climate. In summer, humid air masses come here from temperate latitudes, so summers are 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 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 swampy. In winter, the weather in this climate is influenced by Arctic and Antarctic air masses, so there are long, cold winters, temperatures can reach -50°C. Subpolar climate zones are located only on the northern edges of Eurasia and North America and in the Antarctic waters.
The amount of total solar radiation -- 140-150 kcal/cm 2 in year. Radiation balance on the mainland - 80 kcal/cm 2 per year, on the Ocean - 100-120 kcal/cm 2 in year. Low pressure and weak, unstable winds prevail, favoring the development of thermal convection.
Evaporation is equally great both over the Ocean and over a continent covered with dense vegetation. Absolute humidity air more than 30 g/f 3 over land, relative humidity - 70% even in the driest places. Average monthly temperature air fluctuates from 24 to 28°. The amount of precipitation almost everywhere exceeds possible evaporation and reaches an average of 2000 mm in year. The greatest amount of precipitation generally occurs during the equinox periods, but this pattern is not maintained everywhere.
The continental and oceanic types of equatorial climate differ very little. In the high-mountain equatorial climate, the temperature is slightly lower and the amount of precipitation is less (due to the decrease in moisture content with height). At an altitude of 4500 m lies the border of the belt of eternal snow.
Climates of subequatorial zones (tropical monsoon belts). This climate consists of two climatic regimes: in the summer hemisphere, the equatorial monsoon is directed from the equator and brings moisture; in the winter hemisphere, the monsoon blows towards the equator from the tropics, and air humidity drops.
Continental subequatorial climate is formed on all continents. The boundary of the equatorial monsoons in the interior of the continents lies on average at about 18° N. w. The border extends especially far from the equator in Asia (Hindustan, Indochina).
The continental subequatorial climate is characterized by humid summers, dry winters and dry, hot springs. On the plains, as you move away from the equator, the amount of precipitation decreases. The annual variation of temperature has two minimums (winter and summer) and two maximums (spring and autumn). A slight decrease in temperature in summer is caused by the influence of equatorial air, which at this time is colder than tropical air by several (up to 5) degrees. Precipitation rarely exceeds 2000 mm in year.
In mountainous regions, the temperature decreases with altitude, but the pattern of the annual course of meteorological elements remains the same. On the slopes that receive the equatorial monsoons, the amount of precipitation increases very sharply, reaching a maximum amount.
Oceanic subequatorial climate is observed on all oceans in the northern hemisphere, in the southern hemisphere - over the Indian and western parts of the Pacific and Atlantic Oceans. The border of its distribution lies on average at about 12° latitude. Tropical cyclones occur more frequently near this boundary.
Summer in the oceanic subequatorial climate is wetter and warmer (by 2-3°) than winter. It differs from the continental variety of this climate in higher air humidity and lower temperature.
Tropical climates.
The annual amount of total radiation due to low cloudiness in the tropical zone is greater than in the equatorial zone: on the mainland - 180-200 kcal/cm 2 per year, on the Ocean - 160 kcal/cm 2 V year. However, due to the fact that the effective radiation is also very high, the radiation balance is only 60 kcal/cm 2 per year on the mainland and 80-100 kcal/cm 2 per year on the Ocean.
In anticyclones over the oceans and in pressure depressions of thermal origin over the continents, tropical air is formed, which differs from the air at the equator in lower humidity. For continental tropical air this is explained by very low evaporation, for sea air - by stable stratification of trade winds (trade wind inversion), which interferes with the vertical exchange and transfer of moisture to higher layers of the troposphere.
The continental tropical climate is very dry and hot, with large daily amplitudes of air temperature fluctuations (up to 40°). The average annual air temperature range is about 20°. Relative humidity in summer about 30%. This climate is characteristic of inland deserts of the tropical zone.
With altitude, the air temperature drops and the amount of precipitation increases. The snow line is located at approximately 5300 m, rising to 6000 m in particularly protected areas.
The oceanic tropical climate is similar to the equatorial climate, since the daily and annual amplitudes of temperature fluctuations over the Ocean are relatively small, and differs from the equatorial climate in less cloudiness and stable winds.
The tropical climate of the western coasts of the continents is very unique. It is characterized by relatively low air temperatures (18-20°) and low precipitation (less than 100 mm per year) with high air humidity (80-90%). This is the climate of coastal deserts (Western Sahara, Namib, Atacama, California).
The formation of the climate of the western coast of the continents in the tropical zone is influenced by cold currents and air influx in the eastern part of the subtropical maximum (anticyclone) from the temperate latitudes, enhancing the inversion that exists in the trade winds. As a result, the border temperature inversion is located below the condensation boundary and convection does not develop, and therefore, clouds do not form and precipitation does not fall. The annual temperature variation is the same as in the oceanic type. Fogs are very frequent and breezes are strong.
With height, the air temperature first increases slightly (since the influence of the cold current decreases), then decreases; precipitation does not increase.
The tropical climate of the eastern coasts of the continents differs from the climate of the western coasts in higher temperatures and more precipitation. Due to the influence of the warm current and air brought in the western part of the anticyclone from the equator, the trade wind inversion is weakened and does not interfere with convection.
In the mountains on the windward slopes there is more precipitation, but its amount does not increase with height, since the trade winds are wet only in the lower layer. There is little precipitation on the leeward slopes.
Subtropical climates
In winter, the radiation regime and the nature of circulation develop almost the same as in the temperate zone, in summer - the same as in the tropical zone.
Compared to the tropical zone, the annual amount of solar radiation decreases by about 20%, and its seasonal fluctuations become more noticeable.
In summer, anticyclones are well defined over the oceans, and regions over the continents low blood pressure. In winter, cyclonic activity predominates in the subtropical zone.
Continental subtropical climate. Summer is hot and dry. The average temperature in the summer months is 30° and above, the maximum is more than 50°. Winter is relatively cold, with precipitation. Annual precipitation is about 500 mm, and on the windward slopes of the mountains - four to five times more. In winter, snow falls, but a stable snow cover does not form.
The amount of precipitation increases with altitude. The air temperature drops and above 2000 m above sea level in winter a short time Snow cover remains.
The oceanic subtropical climate differs from the continental subtropical climate in being more uniform annual progress air temperature. Average temperature most warm month about 20°, the coldest about 12°.
Subtropical climate of the western coasts of the continents (Mediterranean). Summer is not hot and dry. Winter is relatively warm and rainy. In summer, the coast comes under the influence of the eastern periphery of the subtropical anticyclone. In winter, cyclonic activity dominates here.
The subtropical climate of the eastern coasts has a monsoon character. Winters, compared to other climates in this zone, are cold and dry, summers are hot and humid. This climate is well expressed only in the northern hemisphere, and especially on the east coast of Asia.
Climates of temperate zones.
The radiation balance on average per year is two times less than in the tropical zone, which largely depends on cloudiness. Moreover, in summer it differs little from the radiation balance of the tropical zone, while in winter on the mainland the radiation balance is negative. The development of cyclonic activity ensures meridional air transport. Precipitation is mainly associated with the passage of cyclones.
Continental temperate climate -- climate of the continents of the northern hemisphere. Summers are warm (can be hot), winters are cold with stable snow cover.
Radiation balance on average per year is 20-30 kcal/cm 2 , in the summer months it differs little from the tropical (6 kcal/cm 2 per month), and in winter it is a negative value (-1 kcal/cm 2 per month).
In summer, there is an intensive transformation of air masses coming from the oceans and the north over the continents. The air heats up and is additionally humidified by moisture evaporated from the surface of the continent. In winter, the air cools in anticyclones. The temperature drops below -- 30°. There is more precipitation in the summer, but prolonged transformation of the air can lead to drought.
In the mountains, summer is much colder than on the plain, and in winter, on the plain (as a result of the entry of cold air masses) it is often colder than in the mountains. On the slopes of the mountains, especially on the western ones, facing the prevailing winds, there is more precipitation than on the plain.
Oceanic temperate climate. The radiation balance of the surface of the oceans on average per year is 1.5 times greater than on the continents. Warm currents bring almost as much heat to temperate latitudes as the radiation balance provides. About 2/3 of the heat is spent on evaporation, the rest goes to warming the atmosphere (turbulent heat exchange) in winter.
Winter over the oceans is much warmer than over the continents, summer is cooler. Cyclonic activity is widespread throughout the year.
The temperate climate of the western coasts of the continents is formed under the influence of the western transfer of air from the Ocean to the continent; differs from the continental one by smaller annual temperature fluctuations. Precipitation falls fairly evenly in all seasons.
The temperate climate of the eastern coasts of the continents is caused by the movement of air in summer from the Ocean to the mainland, and in winter - from the mainland to the Ocean. Summer is rainy, winter is dry and cold. Cold currents lower summer air temperatures, and in spring and early summer they contribute to the formation of fog.
Climates of the subarctic and subantarctic zones
Continental subarctic climate is formed only in the northern hemisphere. Radiation balance 10-12 kcal/cm 2 in year. Summers are relatively warm and short, winters are harsh. The annual amplitude of temperature fluctuations is very large. There is little precipitation (less than 200 mm in year). In summer, northerly winds predominate. The air coming from the north and transforming over the continent approaches the Arctic in its qualities.
In the mountains in winter there is a powerful inversion. There are very large differences between summer and winter temperatures in depressions of the relief, where air exchange is weakened.
The oceanic subarctic and subantarctic climates do not have sharp differences between winter and summer temperatures. The annual temperature range is no more than 20°. Cyclonic activity is widespread throughout the year.
Climates of the Arctic and Antarctic zones
The annual radiation balance is on average close to zero. The snow cover does not melt all year. The high reflectivity of snow leads to the fact that even in summer the radiation balance is very small. So, at station Pionerskaya (70° S) with total radiation in December 24 kcal/cm 2 per month radiation balance on the snow surface is less than 2 kcal
The predominance of anticyclonic weather contributes to constant cooling of the air in the central regions of the Arctic and Antarctic. There is little precipitation. However, precipitation and condensation of moisture on a cold snow surface together exceed evaporation.
The continental polar climate is well expressed in the southern hemisphere. Characterized by very harsh winters and cold summers. Negative average temperature have all months. Marked minimum temperature-88.3°.
Oceanic polar climate is the climate of the northern polar regions, formed over the surface of the ocean covered with ice. The warmth of ocean waters penetrating through the ice plays a significant role in the arrival of heat in winter. From October to April the radiation balance is negative, from May to September it is positive.
The average January temperature in the center of the Arctic (-40°) is higher than in northeast Asia. In summer, as a result of the loss of a large amount of heat through the melting of snow and ice and evaporation, the temperature is about 0°. The weather in summer is mostly cloudy. There is little precipitation (about 100 mm in year).