Changes in the temperature of the world's oceans. Why and how does the water temperature in the World Ocean change? Water temperature and salinity
The climate within the Earth's surface varies zonally. Most modern classification, which explains the reasons for the formation of one or another type of climate, was developed by B.P. Alisov. It is based on types air masses and their movement.
Air masses– these are significant volumes of air with certain properties, the main of which are temperature and moisture content. The properties of air masses are determined by the properties of the surface over which they form. Air masses form the troposphere like the lithospheric plates that make up the earth's crust.
Depending on the area of formation, there are four main types of air masses: equatorial, tropical, temperate (polar) and arctic (Antarctic). In addition to the area of formation, the nature of the surface (land or sea) over which the air accumulates also matters. In accordance with this, the main zonal types of air masses are divided into marine and continental.
Arctic air masses are formed in high latitudes, above the icy surface of the polar countries. Arctic air is characterized by low temperatures and low moisture content.
Moderate air masses clearly divided into marine and continental. Continental temperate air is characterized by low moisture content, high summer and low winter temperatures. Maritime temperate air forms over the oceans. It is cool in summer, moderately cold in winter and constantly humid.
Continental tropical air forms over tropical deserts. It's hot and dry. Sea air is characterized by lower temperatures and significantly higher humidity.
equatorial air, forming in the zone at the equator both over the sea and over land, it has high temperature and humidity.
Air masses constantly move after the sun: in June - to the north, in January - to the south. As a result, territories are formed on the surface of the earth where one type of air mass dominates throughout the year and where air masses replace each other according to the seasons of the year.
The main feature of the climate zone is the dominance of certain types of air masses. are divided into basic(one zonal type of air mass dominates throughout the year) and transitional(air masses change each other seasonally). The main climatic zones are designated in accordance with the names of the main zonal types of air masses. In transition zones, the prefix “sub” is added to the name of the air masses.
Main climatic zones: equatorial, tropical, temperate, arctic (Antarctic); transitional: subequatorial, subtropical, subarctic.
All climatic zones except the equatorial one are paired, that is, they exist in both the Northern and Southern Hemispheres.
In the equatorial climate zone all year round equatorial air masses dominate, low pressure prevails. It is humid and hot throughout the year. Seasons of the year are not expressed.
Tropical air masses (hot and dry) dominate throughout the year tropical zones. Due to the downward movement of air that predominates throughout the year, very little precipitation falls. Summer temperatures here are higher than in the equatorial zone. The winds are trade winds.
For temperate zones characterized by the dominance of moderate air masses throughout the year. Western air transport predominates. Temperatures are positive in summer and negative in winter. Due to the predominance low blood pressure There is a lot of precipitation, especially on the ocean coasts. In winter, precipitation falls in solid form(snow, hail).
In the Arctic (Antarctic) belt Cold and dry arctic air masses dominate all year round. Characterized by downward air movement, north- and south-easterly winds, the predominance of negative temperatures throughout the year, and constant snow cover.
In the subequatorial belt There is a seasonal change in air masses, the seasons of the year are expressed. Due to the arrival of equatorial air masses, summer is hot and humid. In winter, tropical air masses dominate, making it warm but dry.
In the subtropical zone temperate (summer) and arctic (winter) air masses change. Winter is not only harsh, but also dry. Summer is significant warmer than winter, with a lot of rainfall.
Climatic regions are distinguished within climatic zones with different types of climates – maritime, continental, monsoon. Marine climate type formed under the influence of marine air masses. It is characterized by a small amplitude of air temperature across the seasons, high cloudiness, and a relatively large amount of precipitation. Continental type climate forms far from the ocean coast. It is distinguished by a significant annual amplitude of air temperatures, a small amount of precipitation, and distinct seasons. Monsoon climate characterized by changing winds according to the seasons of the year. At the same time, with the change of season, the wind changes direction to the opposite, which affects the precipitation regime. Rainy summer gives way to dry winter.
The largest number of climatic regions is found within the temperate and subtropical zones Northern Hemisphere.
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- Types of climates (climatic zones) of Russia.
General characteristics of the Earth's climate zones.
Climatic zones differ from each other:
- degree of heating by the sun;
- peculiarities of atmospheric circulation;
- seasonal changes in air masses.
Climatic zones differ significantly from each other, gradually changing from the equator to the poles. However, climate is influenced not only by the latitude of the Earth, but also by the terrain, proximity to the sea, and altitude.
In Russia and in most countries of the world, the classification of climate zones created by the famous Soviet climatologist is used B.P. Alisov in 1956.
According to this classification on globe There are four main climatic zones of the Earth and three transitional ones - with the prefix “sub” (Latin “under”):
- Equatorial (1 belt);
- Subequatorial (2 zones - in the northern and southern hemispheres);
- Tropical (2 zones - in the northern and southern hemispheres);
- Subtropical (2 zones - in the northern and southern hemispheres);
- Moderate (2 zones - in the northern and southern hemispheres);
- Subpolar (2 zones - subantarctic in the south, subarctic in the north);
- Polar (2 zones - Antarctic in the south, Arctic in the north);
Within these climatic zones, four types of Earth's climate are distinguished:
- Continental,
- Oceanic,
- The climate of the western shores,
- Climate of the eastern shores.
Let us consider in more detail the climate zones of the Earth and the types of climates inherent in them.
Climatic zones and types of climates of the Earth:
1. Equatorial climate zone– 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.
2. Subequatorial climate – is located between the equatorial and tropical main types of Earth’s climate. In summer, this zone is dominated by equatorial air masses, and in winter by tropical ones. The amount of precipitation in summer is 1000-3000 mm. Average summer temperature is +30°C. In winter there is little precipitation, the average temperature is +14°C.
Subequatorial and equatorial belts. From left to right: savannah (Tanzania), wet forest(South America)
3. Tropical climate zone. In this type of climate, a distinction is made between continental tropical climate and oceanic tropical climate.
- mainland tropical climate – annual precipitation - 100-250 mm. The average summer temperature is +35-40°C, winter +10-15°C. Daily temperature fluctuations can reach 40 °C.
- oceanic tropical climate - annual precipitation – up to 50 mm. The average summer temperature is +20-27°C, winter +10-15°C.
Tropical zones of the Earth. From left to right: deciduous forest(Costa Rica), veld ( South Africa), desert (Namibia).
4. Subtropical climate– is located between the tropical and temperate main types of Earth’s climate. In summer, tropical air masses dominate, and in winter, air masses invade temperate latitudes, carrying precipitation. For subtropical climate characterized by 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.
- dry subtropical climate - observed within continents subtropical latitudes. Summer is hot (up to +50°C) and in winter frosts down to -20°C are possible. Annual precipitation is 120 mm or less.
- Mediterranean climate – observed in western parts continents. Summer is hot, without precipitation. Winter is cool and rainy. The annual precipitation is 450-600 mm.
- subtropical climate of the eastern coasts continents is monsoon. Winter, compared to other climates of the subtropical zone, is cold and dry, and summer is hot (+25°C) and humid (800 mm).
Subtropical zones of the Earth. From left to right: evergreen forest (Abkhazia), prairie (Nebraska), desert (Karakum).
5. Temperate climate zone. Formed over areas of temperate latitudes - from 40-45° north and south latitude to the polar circles. Annual precipitation ranges from 1000 mm to 3000 mm along the outskirts of the continent and up to 100 mm in inland areas. Temperatures in summer range from +10°C to +25-28°C. In winter - from +4°С to -50°С. In this type of climate, a distinction is made between marine, continental and monsoon climates.
- maritime temperate climate – annual precipitation - from 500 mm to 1000 mm, in the mountains up to 6000 mm. Summers are cool +15-20°C, winters are warm from +5°C.
- continental temperate climate – annual precipitation is about 400 mm. Summers are warm (+17-26°C), and winters are cold (-10-24°C) with stable snow cover for many months.
- monsoon temperate climate - annual precipitation is about 560 mm. Winter is clear and cold (-20-27°C), summer is humid and rainy (-20-23°C).
Natural zones of the Earth's temperate zones. From left to right: taiga (Sayan Mountains), deciduous forest (Krasnoyarsk Territory), steppe (Stavropol region), desert (Gobi).
6.
Subpolar climate- consists of subarctic and subantarctic climatic zones. 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). 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.
7.
Polar climate type - Arctic and Antarctic climate zones. Forms above 70° north and below 65° south latitudes. The air is very cool, the snow cover does not melt all year. 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 is not higher than 0°C, winter - -20-40°C.
Subpolar climate zones of the Earth. From left to right: Arctic desert (Greenland), tundra (Yakutia), forest-tundra (Khibiny).
The characteristics of the Earth's climates are presented more clearly in the table.
Characteristics of the Earth's climatic zones. Table.
Note: Dear visitors, hyphens in long words in the table are placed for the convenience of mobile users - otherwise the words will not be transferred and the table will not fit on the screen. Thanks for understanding!
Climate type |
Climate zone |
Atmospheric circulation |
Territory |
|||
January |
July |
|||||
Equatorial |
Equatorial |
Within a year. 2000 |
Warm and humid equatorial air masses form in areas of low atmospheric pressure |
Equatorial regions of Africa, South America and Oceania |
Climate type |
Climate zone |
Average temperature, °C |
Mode and quantity atmospheric precipitation, mm |
Atmospheric circulation |
Territory |
|
January |
July |
|||||
Tropical monsoon |
Subequatorial |
Mainly during the summer monsoon, 2000 |
South and Southeast Asia, Western and Central Africa, Northern Australia |
Climate type |
Climate zone |
Average temperature, °C |
Mode and amount of precipitation, mm |
Atmospheric circulation |
Territory |
|
January |
July |
|||||
Mediterranean |
Subtropical |
Mainly in winter, 500 |
In summer - anti-cyclones at high atmospheric pressure; in winter - cyclonic activity |
Mediterranean, Southern coast of Crimea, South Africa, Southwestern Australia, Western California |
Climate type |
Climate zone |
Average temperature, °C |
Mode and amount of precipitation, mm |
Atmospheric circulation |
Territory |
|
January |
July |
|||||
Arctic (Antarctic) |
Arctic (Antarctic) |
During the year, 100 |
Anticyclones predominate |
The waters of the Arctic Ocean and the continent of Antarctica |
Types of climates (climatic zones) of Russia:
- Arctic: January t −24…-30, summer t +2…+5. Precipitation - 200-300 mm.
- Subarctic: (up to 60 degrees N). summer t +4…+12. Precipitation is 200-400 mm.
- Moderate continental: January t −4…-20, July t +12…+24. Precipitation 500-800 mm.
- Continental climate: January t −15…-25, July t +15…+26. Precipitation 200-600 mm.
Characteristics of climatic zones (the table below) is the topic of this article. We will talk about what types of climate exist on our planet, and also consider each of them in detail. To do this, recall that climate is the weather pattern established over the years, which depends on the specific territory and its geographical location.
Equatorial belt
This climate zone is characterized by low pressure, as well as the year-round presence of air masses. There are no separate climatic regions within the belt. As for the temperature, it is hot here. There is a lot of precipitation throughout the year and there is plenty of moisture. The weather here changes very dramatically during the day. The first half is sultry, and the second half begins with heavy rains.
The names of climate zones are associated with their characteristics. The equatorial belt is located near the equator, which is why it has this name.
The subequatorial belt is characterized by changes in air masses that occur seasonally. In summer, equatorial air masses predominate, and in winter, more tropical ones. Weather conditions in summer are fully consistent equatorial type climate, while the weather in winter resembles tropical conditions. Winter is dry and slightly colder than summer.
Tropical zone
As we already know, the names of climate zones are associated with their location. This type of climate is characterized by tropical air masses all year round. The air is continental. The real weather of the tropical zone is high pressure and temperature, a large temperature difference not only throughout the year, but also during the day. Water is very scarce in this climate. It is very hot and dry here, and dry winds often occur. There is almost no rain. The weather is usually dry and sunny.
However, the tropical belt is deceptive. The eastern shores of the continents, which are washed by warm currents, are also in this zone, but have a different climate. Marine tropical air, heavy rainfall, monsoons. Climatic conditions are similar to the equatorial climate.
Subtropical zones are characterized by changes in air masses. The climate is tropical in summer and temperate in winter. Pressure surges in summer and winter are quite high. In winter the pressure is low and in summer it is high. Despite the strong differences in temperature and precipitation throughout the year, the thermometer is above zero the entire year. Sometimes the temperature can even drop to negative values. During such periods snow falls. In flat areas it melts quickly, but in the mountains it can remain for several months. As for the winds, the trade winds rule in winter and the trade winds in summer.
Temperate zone
The temperature of climatic zones largely depends on the air masses that prevail over the territory. IN temperate zone, as the name suggests, a temperate climate. But not always. Sometimes tropical or arctic air masses invade. The temperate climate is characterized big difference temperatures Summers are hot, and winters are cold and long. Relatively low pressure, cyclonicity, instability weather conditions in winter. They blow throughout the year westerly winds, in summer there are sometimes trade winds, and in winter - northeast winds. Massive snow cover every winter.
Arctic and Antarctic belts
In the characteristics of climate zones in the table, you can see what temperatures prevail in these zones. The features of these belts are low temperatures all year round, strong winds and cold summers. There is very little precipitation.
Subarctic and subantarctic belts
These zones are distinguished by the fact that in summer a temperate climate prevails here. Because of this, a large amplitude of temperature fluctuations occurs. There is a lot in these belts permafrost. In winter, north-east and south-east winds predominate, and in summer - westerlies. The belts have 2 climatic regions, about them below.
Territories of climate zones
Each belt is characteristic of certain territory. Natural climatic zones have been formed on the planet for a long time, so we can confidently identify certain areas in which the climate of the zone is pronounced.
The equatorial climate is characteristic of Oceania, South America and Africa. Subequatorial climate is typical for Northern Australia and South- East Asia. Central part Australia and North Africa are a tropical zone. Subtropics are characteristic of the interior regions of continents. A temperate climate prevails in the western part and eastern outskirts of Eurasia. the belt prevails in North America and northern part of Eurasia. The Arctic and Antarctic belts are characteristic of Australia and the Arctic Ocean.
Table of climate zones
The table shows the characteristics of the zones.
Belt | Average temperature in January | Average temperature in July | Atmosphere |
Equatorial | Moist warm air masses |
||
Subequatorial | Monsoons prevail |
||
Tropical | |||
Subtropical | Cyclonicity, high atmospheric pressure |
||
Moderate | Western winds and monsoons |
||
Subarctic | |||
Arctic (Antarctic) | Anticyclones |
Climatic regions of the belts
Subtropical zones have three climatic regions:
- Mediterranean climate. Prevails in the northern hemisphere, on the southern and western shores of continents. In summer it is observed continental climate, and in winter - continental and maritime air masses. Summers are dry and warm, and winters are relatively cool and wet. Insufficient hydration.
- Monsoon climate. Distributed on the eastern shores of continents. Summer monsoons cause extreme heat and a lot of rainfall, and the winter monsoons are cool and dry. Humidity in this area is moderate. Precipitation is typical for the winter season.
- Marine climate. Distributed on the continents of the southern hemisphere. Marine air masses are characteristic. Summer and winter are warm. There is enough moisture, it is distributed evenly throughout the year.
The temperate zone consists of 5 climatic regions:
- Moderate Prevails on the western shores of continents. The weather is formed under the influence of warm currents and westerly winds. Winters are quite mild and summers are warm. There will be a lot of precipitation throughout the year. Winter is characterized by heavy and frequent snowfalls. There is more than enough moisture. The geography of the climate zone contributes to weather instability.
- Continental temperate climate. Characterized by warm summers and cold winters. Arctic air masses sometimes provoke a sharp cooling, and tropical air masses - warming. There is little precipitation, it is uniform (cyclonic and frontal).
- Continental climate. Applies only to the northern hemisphere. Moderate air masses prevail here throughout the year. Sometimes arctic air masses appear (in this area their invasion is possible even in summer). IN warm time There is more precipitation every year, but overall it is insignificant. A small amount of snow and the predominance of low temperatures contribute to the existence of permafrost.
- Sharply continental climate. Characteristic of the interior regions of North America and Eurasia. The territory is practically isolated from the influence of seas and oceans and is located in the center of high pressure. Sometimes summer is hot, winter is always frosty. There is a lot of permafrost. Weather type - anticyclonic. There is little precipitation and little moisture.
- Monsoon climate. Distributed on the eastern side of continents. Characterized by the seasonality of air masses. Summers are humid and warm, while winters are dry and cool. Summer precipitation is more numerous and there is excess moisture.
The subarctic and subantarctic belts have two regions:
- continental climate (severe but short winters, little precipitation, swampy areas);
- oceanic climate (fog, high rainfall, mild winters and cool summers).
The characteristics of climatic zones in the table do not include two areas of the Arctic and Antarctic zones:
- continental (little precipitation, temperatures below zero all year);
- oceanic climate (cyclones, little precipitation, negative temperatures).
Temperatures in oceanic climates can rise to +5 during the polar day.
To summarize, let's say that the characteristics of climatic zones (in the table) are necessary for every educated person.
Climate is a long-term weather regime characteristic of a given area due to its geographical location.
Climate is a statistical ensemble of states through which the system passes: hydrosphere → lithosphere → atmosphere over several decades. Climate is usually understood as the average value of weather over a long period of time (of the order of several decades), that is, climate is average weather. Thus, weather is the instantaneous state of some characteristics (temperature, humidity, atmospheric pressure). Deviation of weather from the climate norm cannot be considered as climate change; for example, a very cold winter does not indicate a cooling of the climate. To detect climate change, a significant trend in atmospheric characteristics over a long period of time of the order of ten years is needed. The main global geophysical cyclic processes that form climatic conditions on Earth are heat circulation, moisture circulation and general atmospheric circulation.
In addition to the general concept of “climate”, there are the following concepts:
- The climate of the free atmosphere is studied by aeroclimatology.
- Microclimate
- Macroclimate is the climate of territories on a planetary scale.
- Ground air climate
- local climate
- Soil climate
- phytoclimate - climate of plants
- urban climate
Climate is studied by the science of climatology. Paleoclimatology studies climate change in the past.
In addition to the Earth, the concept of “climate” can refer to other celestial bodies (planets, their satellites and asteroids) that have an atmosphere.
Climatic zones and climate types
Climatic zones and climate types vary significantly by latitude, from the equatorial zone to the polar, but climate zones are not the only factor, the proximity of the sea, the atmospheric circulation system and altitude also have an important influence.
In Russia and in the territory of the former USSR, a classification of climate types was used, created in 1956 by the famous Soviet climatologist B.P. Alisov. 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 the southern hemisphere - Antarctic). Between the main zones there are transitional zones - subequatorial belt, subtropical, subpolar (subarctic and subantarctic). In these climatic zones, in accordance with the prevailing circulation of air masses, four types of climate can be distinguished: continental, oceanic, western climate and eastern coastal climate.
Equatorial belt
Equatorial climate is a climate where the winds are weak, temperature fluctuations are small (24-28 °C at sea level), and precipitation is very abundant (from 1.5 thousand to 5 thousand mm per year) and falls evenly throughout the year.
Subequatorial belt
- Tropical monsoon climate - here in the summer, instead of the eastern trade wind transport between the tropics and the equator, a western air transport occurs (summer monsoon), bringing most of the precipitation. On average, they fall almost as much as in the equatorial climate. On the mountain slopes facing the summer monsoon, precipitation is greatest for the respective regions; the warmest month usually occurs immediately before the onset of the summer monsoon. Characteristic of some areas of the tropics (Equatorial Africa, South and Southeast Asia, Northern Australia). IN East Africa and in Southwest Asia the highest average annual temperatures on Earth are observed (30-32 °C).
- Monsoon climate on tropical plateaus
Tropical zone
- Tropical dry climate
- Tropical humid climate
Subtropical zone
- Mediterranean climate
- Subtropical continental climate
- Subtropical monsoon climate
- High subtropical highlands climate
- Subtropical ocean climate
Temperate zone
- Temperate maritime climate
- Temperate continental climate
- Temperate continental climate
- Moderate continental climate
- Temperate monsoon climate
Subpolar belt
- Subarctic climate
- Subantarctic climate
Polar belt: Polar climate
- Arctic climate
- Antarctic climate
The classification of climates proposed by the Russian scientist W. Koeppen (1846-1940) is widespread in the world. It is based on the temperature regime and the degree of humidification. According to this classification, there are eight climatic zones with eleven climate types. Each type has precise parameters for temperature values, amount of winter and summer precipitation.
Also in climatology, the following concepts related to climate characteristics are used:
- Continental climate is “a climate that is formed under the influence of large land masses on the atmosphere; distributed in the interior regions of continents. It is characterized by large daily and annual air temperature amplitudes.”
- Marine climate is “a climate that is formed under the influence of the atmosphere of oceanic spaces. It is most pronounced over the oceans, but also extends to areas of continents exposed to frequent influences of marine air masses.”
- Mountain climates - “climatic conditions in mountainous areas" The main reason for the differences between the climate of the mountains and the climate of the plains is the increase in altitude above sea level. In addition, important features are created by the nature of the terrain (degree of dissection, relative height and direction of mountain ranges, exposure of slopes, width and orientation of valleys), and glaciers and firn fields have their influence. There are actually mountain climates at altitudes less than 3000-4000 m and alpine climate at high altitudes.
- Arid climate - “climate of deserts and semi-deserts”. Large daily and annual air temperature amplitudes are observed here; almost complete absence or insignificant amount of precipitation (100-150 mm per year). The resulting moisture evaporates very quickly.”
- Humid climate is a climate with excess moisture, in which solar heat arrives in quantities insufficient to evaporate all the moisture that comes in the form of precipitation.
- Nival climate - “a climate where more solid precipitation falls than can melt and evaporate.” As a result, glaciers are formed and snowfields are preserved.
- Solar climate (radiation climate) - theoretically calculated intake and distribution around the globe solar radiation(without taking into account local climate-forming factors.
- Monsoon climate is a climate in which the change in seasons is caused by a change in the direction of the monsoon. Typically, a monsoon climate has a summer with heavy rainfall and a very dry winter. Only in the eastern part of the Mediterranean, where the summer monsoon direction is from the land and the winter monsoon is from the sea, does the bulk of precipitation fall in winter.
- Trade wind climate
Brief description of Russian climates:
- Arctic: January t −24…-30, summer t +2…+5. Precipitation - 200-300 mm.
- Subarctic: (up to 60 degrees N). summer t +4…+12. Precipitation is 200-400 mm.
- Moderate continental: January t −4…-20, July t +12…+24. Precipitation 500-800 mm.
- Continental climate: January t −15…-25, July t +15…+26. Precipitation 200-600 mm.
- Sharply continental: t January −25…-45, t July +16…+20. Precipitation is more than 500 mm.
- Monsoon: January t −15…-30, July t +10…+20. Precipitation 600-800. mm
Study methods
Long-term series are needed to identify climate features, both typical and rarely observed. meteorological observations. In temperate latitudes, 25-50 year series are used; in the tropics their duration may be shorter.
Climatic characteristics are statistical conclusions from long-term series of weather observations, primarily over the following basic meteorological elements: atmospheric pressure, wind speed and direction, air temperature and humidity, cloudiness and precipitation. They also take into account the duration of solar radiation, visibility range, temperature of the upper layers of soil and reservoirs, evaporation of water from earth's surface into the atmosphere, the height and condition of the snow cover, various atmospheric phenomena and ground hydrometeors (dew, ice, fog, thunderstorms, blizzards, etc.). In the 20th century, the number climate indicators included the characteristics of the elements heat balance the earth's surface, such as total solar radiation, radiation balance, the amount of heat exchange between the earth's surface and the atmosphere, heat loss for evaporation.
Long-term averages meteorological elements(annual, seasonal, monthly, daily, etc.), their amounts, frequency of occurrence, etc. are called climate norms; corresponding values for individual days, months, years, etc. are considered as a deviation from these norms. To characterize the climate, complex indicators are also used, that is, functions of several elements: various coefficients, factors, indices (for example, continentality, aridity, humidification), etc.
Special climate indicators are used in applied branches of climatology (for example, sums of growing season temperatures in agroclimatology, effective temperatures in bioclimatology and technical climatology, degree days in calculations heating systems etc.).
General atmospheric circulation models are used to estimate future climate changes.
Climate-forming factors
The climate of the planet depends on a whole complex of external and internal factors. Majority external factors influence the total amount of solar radiation received by the planet, as well as its distribution across seasons, hemispheres and continents.
External factors
Parameters of the earth's orbit and axis
- The distance between the Earth and the Sun determines the amount of solar energy received by the Earth.
- The inclination of the Earth's rotation axis to the orbital plane determines seasonal changes.
- The eccentricity of the Earth's orbit - affects the distribution of heat between the Northern and Southern Hemispheres, as well as seasonal changes.
Milankovitch cycles - during the course of its history, planet Earth quite regularly changes the eccentricity of its orbit, as well as the direction and angle of inclination of its axis. These changes are commonly called “Milankovitch cycles.” There are 4 Milankovitch cycles:
- Precession - rotation earth's axis under the influence of the attraction of the Moon, and also (to a lesser extent) the Sun. As Newton found out in his Principia, the oblateness of the Earth at the poles leads to the fact that gravity external bodies rotates the earth's axis, which describes a cone with a period (according to modern data) of approximately 25,776 years, as a result of which the seasonal intensity amplitude changes solar flow in the northern and southern hemispheres of the Earth;
- Nutation is a long-period (so-called secular) oscillation of the angle of inclination of the earth's axis to the plane of its orbit with a period of about 41,000 years;
- Long-period fluctuations in the eccentricity of the Earth's orbit with a period of about 93,000 years.
- The movement of the perihelion of the Earth's orbit and the ascending node of the orbit with a period of 10 and 26 thousand years, respectively.
Since the described effects are periodic with a non-multiple period, fairly long epochs regularly arise when they have a cumulative effect, reinforcing each other. Milankovitch cycles are commonly used to explain the Holocene climate optimum;
- Solar activity with 11-year, secular and thousand-year cycles;
- The difference in the angle of incidence of sunlight at different latitudes, which affects the degree of heating of the surface and, consequently, the air;
- The speed of rotation of the Earth practically does not change, it is constantly active factor. Due to the rotation of the Earth, trade winds and monsoons exist, and cyclones are also formed.
- Asteroid falls;
- Ebbs and flows caused by the action of the moon.
Internal factors
- The configuration and relative position of the oceans and continents - the appearance of a continent in the polar latitudes can lead to cover glaciation, and the removal of a significant amount of water from the daily cycle, also the formation of supercontinents Pangea has always been accompanied by a general aridization of the climate, often against the background of glaciation, and the location of the continents has a great influence on ocean current system;
- Volcanic eruptions can cause short-term climate change, up to a volcanic winter;
- The albedo of the earth's atmosphere and surface affects the amount of reflected sunlight;
- Air masses (depending on the properties of air masses, the seasonality of precipitation and the state of the troposphere is determined);
- The influence of oceans and seas (if the area is remote from the seas and oceans, then the continental climate increases. The presence of nearby oceans softens the climate of the area, with the exception of the presence of cold currents);
- The nature of the underlying surface (relief, landscape features, presence and condition of ice covers);
- Human activities (fuel combustion, emissions of various gases, agricultural activities, forest destruction, urbanization);
- Heat flows of the planet.
Atmospheric circulation
General atmospheric circulation is a set of large-scale air currents over the earth's surface. In the troposphere, these include trade winds, monsoons, as well as air mass transfers associated with cyclones and anticyclones. Atmospheric circulation exists due to the uneven distribution of atmospheric pressure caused by the fact that at different latitudes of the Earth its surface is heated differently by the sun and the earth's surface has different physical properties, especially due to its division into land and sea. As a result of the exchange of heat between the earth's surface and the atmosphere due to uneven heat distribution, there is constant circulation atmosphere. The energy of atmospheric circulation is constantly spent on friction, but is continuously replenished due to solar radiation. In the warmest places, heated air has a lower density and rises, thus forming a zone of low atmospheric pressure. Similarly, a zone of high pressure is formed in colder places. Air movement occurs from an area of high atmospheric pressure to an area of low atmospheric pressure. Since the closer to the equator and further from the poles the area is located, the better it warms up, in lower layers atmosphere there is a predominant movement of air from the poles to the equator. However, the Earth also rotates on its axis, so the Coriolis force acts on the moving air and deflects this movement to the west. In the upper layers of the troposphere, a reverse movement of air masses is formed: from the equator to the poles. Its Coriolis force constantly deflects to the east, and the further, the more. And in areas around 30 degrees north and south latitude, the movement becomes directed from west to east, parallel to the equator. As a result, the air that reaches these latitudes has nowhere to go at such a height, and it sinks down to the ground. This is where the area of highest pressure forms. This is how trade winds are formed - constant winds, blowing towards the equator and to the west, and since the turning force acts constantly, when approaching the equator, the trade winds blow almost parallel to it. Air currents the upper layers, directed from the equator to the tropics, are called anti-trade winds. Trade winds and anti-trade winds, as it were, form an air wheel through which a continuous circulation of air is maintained between the equator and the tropics. During the year, this zone shifts from the equator to the warmer summer hemisphere. As a result, in some places, especially in the pool Indian Ocean, where the main direction of air transfer in winter is from west to east, in summer it is replaced by the opposite. Such air transfers are called tropical monsoons. Cyclonic activity connects the tropical circulation zone with the circulation in temperate latitudes and an exchange of warm and cold air occurs between them. As a result of interlatitudinal air exchange, heat is transferred from low latitudes to high latitudes and cold from high latitudes to low latitudes, which leads to the preservation of thermal equilibrium on Earth.
In fact, the circulation of the atmosphere is constantly changing, both due to seasonal changes in the distribution of heat on the earth's surface and in the atmosphere, and due to the formation and movement of cyclones and anticyclones in the atmosphere. Cyclones and anticyclones generally move toward the east, with cyclones deflecting toward the poles and anticyclones deflecting away from the poles.
This creates:
high pressure zones:
- on both sides of the equator at latitudes of about 35 degrees;
- near the poles at latitudes above 65 degrees.
low pressure zones:
- equatorial depression - along the equator;
- subpolar depressions - in subpolar latitudes.
This pressure distribution corresponds to a westerly transport in temperate latitudes and an eastern transport in tropical and high latitudes. In the Southern Hemisphere, the zonality of atmospheric circulation is better expressed than in the Northern Hemisphere, since there are mainly oceans there. The wind in the trade winds changes slightly and these changes do little to change the nature of the circulation. But sometimes (on average about 80 times a year) in some areas of the intertropical convergence zone (“an intermediate zone of approximately several hundred km in width between the Northern and Southern hemispheres"), strong vortices develop - tropical cyclones (tropical hurricanes), which sharply, even catastrophically, change the established circulation regime and weather on their way in the tropics, and sometimes even beyond them. In extratropical latitudes, cyclones are less intense than tropical ones. The development and passage of cyclones and anticyclones is an everyday phenomenon. The meridional components of atmospheric circulation associated with cyclonic activity in extratropical latitudes change quickly and frequently. However, it happens that for several days and sometimes even weeks, extensive and high cyclones and the anticyclones hardly change their position. Then oppositely directed long-term meridional air transfers occur, sometimes throughout the entire thickness of the troposphere, which spread over large areas and even over the entire hemisphere. Therefore, in extratropical latitudes, two main types of circulation are distinguished over the hemisphere or a large sector of it: zonal, with a predominance of zonal, most often westerly, transport, and meridional, with adjacent air transport towards low and high latitudes. The meridional type of circulation carries out significantly greater interlatitudinal heat transfer than the zonal one.
Atmospheric circulation also ensures the distribution of moisture both between and within climatic zones. The abundance of precipitation in the equatorial belt is ensured not only by its own high evaporation, but also by the transfer of moisture (due to the general circulation of the atmosphere) from the tropical and subequatorial belts. In the subequatorial belt, atmospheric circulation ensures the change of seasons. When the monsoon blows from the sea, it rains heavily. When the monsoon blows from the dry land, the dry season begins. The tropical zone is drier than the equatorial and subequatorial zones, since the general circulation of the atmosphere transports moisture to the equator. In addition, winds prevail from east to west, therefore, thanks to moisture evaporated from the surface of the seas and oceans, eastern parts The continents receive quite a lot of rain. Further west there is not enough rain, the climate becomes arid. This is how entire desert belts are formed, such as the Sahara or the deserts of Australia.
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Climate- This is a long-term weather regime characteristic of a particular area. It manifests itself in the regular change of all types of weather observed in this area.
Climate influences living and inanimate nature. Are closely dependent on climate water bodies, soil, vegetation, animals. Certain 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 reaching the earth's surface; atmospheric circulation; the nature of the underlying surface. At the same time, climate-forming factors themselves depend on geographical conditions of this area, primarily from geographical latitude.
The geographic latitude of the area determines the angle of incidence of the sun's rays, obtaining a certain amount of heat. However, receiving heat from the Sun also depends on proximity to the ocean. In places far from the oceans, there is little precipitation, and the mode of precipitation is uneven (in warm period more than in cold weather), cloudiness is low, winter is cold, summer is warm, the annual temperature range is large. This climate is called continental, as it is typical for places located in the interior of continents. A maritime climate is formed over the water surface, which is characterized by: a smooth variation in air temperature, with small daily and annual temperature amplitudes, large clouds, and a uniform and fairly large amount of precipitation.
The climate is also 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, with most of the island of Greenland lying at approximately the same latitudes as the Scandinavian Peninsula, but outside the zone of influence warm current, is covered with a thick layer of ice all year round.
A major role in climate formation belongs to relief. You already know that with every kilometer the terrain rises, the air temperature drops by 5-6 °C. Therefore, on the high mountain slopes of the Pamirs the average annual temperature is 1 °C, although it is located just north of the tropics.
The location of mountain ranges has a great influence on the climate. For example, the Caucasus Mountains retain wet sea winds, and on their windward slopes facing the Black Sea, significantly more precipitation falls than on the leeward ones. At the same time, the mountains serve as an obstacle to cold northern winds.
There is a dependence of climate on prevailing winds. On the territory of the East European Plain, westerly winds coming from the Atlantic Ocean prevail throughout almost the entire year, so winters in this territory are relatively mild.
Districts Far East are under the influence of monsoons. In winter, winds from the interior of the mainland constantly blow here. They are cold and very dry, so there is little precipitation. In summer, on the contrary, 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 year in the area.
Climatic characteristics are statistical conclusions from long-term weather observation series (25-50 year series are used in temperate latitudes; in the tropics their duration may be shorter), primarily on the following basic 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, visibility range, temperature of the upper layers of soil and reservoirs, evaporation of water from the earth's surface into the atmosphere, height and condition of snow cover, various atmospheric phenomena and ground hydrometeors (dew, ice, fog, thunderstorms, blizzards, etc.) . In the 20th century The climatic indicators included the characteristics of the elements of the heat balance of the earth's surface, such as total solar radiation, radiation balance, the amount of 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.
Climate zones
Long-term average values of meteorological elements (annual, seasonal, monthly, daily, etc.), their sums, frequency, etc. are called climate standards: corresponding values for individual days, months, years, etc. are considered as a deviation from these norms.
Maps with climate indicators are called climatic(temperature distribution map, pressure distribution map, etc.).
Depending on 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 zones there are transitional climatic zones: subequatorial, subtropical, subarctic, subantarctic. In transitional zones, air masses change seasonally. They come here from neighboring zones, so the climate is sub equatorial belt in summer it 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 zones, and in winter - to 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. For example, in the tropical zone of Africa, areas of tropical dry and tropical humid climate, and in Eurasia the subtropical zone is divided into areas of Mediterranean, continental and monsoon climate. IN mountainous areas An altitudinal zone is formed due to the fact that the air temperature decreases with altitude.
Diversity of Earth's climates
The climate classification provides an orderly system for characterizing climate types, their zoning and mapping. Let us give examples of climate types that prevail over vast territories (Table 1).
Arctic and Antarctic climate zones
Antarctic and Arctic climate dominates in Greenland and Antarctica, where 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 sun rays fall onto the earth's surface at a slight angle, which reduces the efficiency of heating. Most of the incoming solar radiation is reflected by the ice. In both summer and winter, low temperatures prevail in the higher regions of the Antarctic ice sheet. The climate of the interior of Antarctica is much colder climate The Arctic, since the southern continent is large in size and altitude, and the Arctic Ocean moderates the climate, despite the widespread distribution of pack ice. During short periods of warming in summer, drifting ice sometimes melts. Precipitation on ice sheets falls in the form of snow or small particles of freezing fog. Inland areas receive only 50-125 mm of precipitation annually, but the coast can receive more than 500 mm. 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, carrying snow to the coast.
Table 1. Climates of the Earth
Climate type |
Climate zone |
Average temperature, °C |
Mode and amount of atmospheric precipitation, mm |
Atmospheric circulation |
Territory |
|
Equatorial |
Equatorial |
Within a year. 2000 |
In areas of low atmospheric pressure, warm and humid equatorial air masses form |
Equatorial regions of Africa, South America and Oceania |
||
Tropical monsoon |
Subequatorial |
Mainly during the summer monsoon, 2000 |
South and Southeast Asia, Western 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; in winter - cyclonic activity |
Mediterranean, Southern coast of Crimea, South Africa, Southwestern Australia, Western California |
||
Subtropical dry |
Subtropical |
Within a year. 120 |
Dry continental air masses |
Interiors of continents |
||
Temperate marine |
Moderate |
Within a year. 1000 |
Western winds |
Western parts of Eurasia and North America |
||
Temperate continental |
Moderate |
Within a year. 400 |
Western winds |
Interiors of continents |
||
Moderate monsoon |
Moderate |
Mainly during the summer monsoon, 560 |
Eastern edge of Eurasia |
|||
Subarctic |
Subarctic |
During the year, 200 |
Cyclones predominate |
Northern edges of Eurasia and North America |
||
Arctic (Antarctic) |
Arctic (Antarctic) |
During the year, 100 |
Anticyclones predominate |
The Arctic Ocean and mainland Australia |
Subarctic continental climate is formed in the north of the continents (see. climate map atlas). In winter, arctic air predominates here, which forms in areas of high pressure. Arctic air spreads to the eastern regions of Canada from the Arctic.
Continental subarctic climate in Asia is characterized by the largest annual amplitude of air temperature on the globe (60-65 °C). The continental climate here reaches its maximum value.
The average temperature in January varies across the territory from -28 to -50 °C, and in the lowlands and basins due to stagnation of air, its temperature is even lower. A record for the Northern Hemisphere was recorded in Oymyakon (Yakutia). negative temperature air (-71 °C). The air is very dry.
Summer in subarctic zone although short, it is quite warm. The average monthly temperature in July ranges from 12 to 18 °C (daytime maximum is 20-25 °C). During the summer, more than half of the annual 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 compared to the corresponding climate of Asia. There are less cold winters and colder summers.
Temperate climate zone
Temperate climate west coasts continents has pronounced features of a marine climate and is characterized by the predominance of marine air masses throughout the year. It is observed on the Atlantic coast of Europe and the Pacific coast of North America. The Cordillera is a natural boundary separating the coast with a maritime climate from inland areas. The European coast, except Scandinavia, is open to free access of temperate sea air.
The constant transport of sea air is accompanied by large clouds and causes long springs, in contrast to the interior of the continental regions of Eurasia.
Winter in temperate zone It's warm on the western coasts. The warming influence of the oceans is enhanced by warm sea currents, washing western shores continents. The average temperature in January is positive and varies across the territory from north to south from 0 to 6 °C. When arctic air invades, it can drop (on the Scandinavian coast to -25 °C, and on the French coast - to -17 °C). As tropical air spreads northward, the temperature rises sharply (for example, it often reaches 10 °C). In winter, on the western coast of Scandinavia, large positive temperature deviations from the average latitude (by 20 °C) are observed. The temperature anomaly on the Pacific coast of North America is smaller and amounts to no more than 12 °C.
Summer is rarely hot. The average temperature in July is 15-16 °C.
Even during the day, the air temperature rarely exceeds 30 °C. Due to frequent cyclones, all seasons are characterized by cloudy and rainy weather. There are especially many cloudy days on the west coast of North America, where cyclones are forced to slow down in front of the Cordillera mountain systems. In connection with this great monotony is characterized by the weather regime in southern Alaska, where there are no seasons in our understanding. Eternal autumn reigns there, and only plants remind of the onset of winter or summer. Annual precipitation ranges from 600 to 1000 mm, and on the slopes of mountain ranges - from 2000 to 6000 mm.
In conditions of sufficient moisture on the coasts, developed broadleaf forests, and in conditions of excess - conifers. Flaw summer warmth reduces the upper limit of the forest in the mountains to 500-700 m above sea level.
Temperate climate of the eastern coasts of the continents has monsoon features and is accompanied by a seasonal change in winds: in winter, northwestern currents predominate, in summer - southeastern ones. It is well expressed on the eastern coast of Eurasia.
In winter, with the north-west 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). Predominantly clear, dry, windy weather. There is little precipitation in the southern coastal areas. 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 heavy snow cover, especially in Kamchatka, where it maximum height reaches 2 m.
In summer, temperate sea air spreads along the Eurasian coast with a southeast wind. Summers are warm, with an average July temperature of 14 to 18 °C. Frequent precipitation is caused by cyclonic activity. Their annual quantity is 600-1000 mm, with most of it falling in the summer. Fogs are common at this time of year.
Unlike Eurasia, the east coast of North America is characterized by monkfish climate, which are expressed in the predominance of winter precipitation and marine type annual progress air temperatures: the minimum occurs in February, and the maximum in August, when the ocean is 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 the snowdrifts reaches 2.5 m. With a southerly wind, there is often black ice. Therefore, some streets in some cities in eastern Canada have iron railings for pedestrians. Summer is cool and rainy. Annual precipitation is 1000 mm.
Temperate continental climate most clearly expressed on the Eurasian continent, especially in the regions of Siberia, Transbaikalia, northern Mongolia, as well as in 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 winter months With a negative radiation balance, the earth's surface cools. The cooling effect of the land surface on the surface layers of air is especially great in Asia, where in winter a powerful Asian anticyclone forms and partly cloudy, windless 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 midwinter, the continental air in the lower layers becomes even colder than the Arctic air. This one is very cold air The Asian anticyclone extends to Western Siberia, Kazakhstan, and 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 continent, as in Asia, but, on the contrary, decreases somewhat due to the frequent passage of cyclones. Continental temperate air in North America has a higher temperature than continental temperate air in Asia.
The formation of a continental temperate climate is significantly influenced by the geographical features of the continents. In North America mountain ranges The Cordillera is a natural boundary separating the coast with a maritime climate from the inland areas with a continental climate. In Eurasia, a temperate continental climate is formed over a vast expanse of land, from approximately 20 to 120° E. d. Unlike North America, Europe is open to the free penetration of sea air from the Atlantic deep into its interior. This is facilitated not only by the westerly transport of air masses, which dominates in temperate latitudes, but also by the flat nature of the relief, highly rugged coastlines and deep penetration of the Baltic and North Seas into the land. Therefore, a temperate climate of a lesser degree of continentality is formed over Europe compared to Asia.
In winter, sea Atlantic air moving over cold surface sushi of the temperate latitudes of Europe, retains its physical properties for a long time, and its influence extends throughout Europe. In winter, as the Atlantic influence weakens, the air temperature decreases from west to east. In Berlin it is 0 °C in January, in Warsaw -3 °C, in Moscow -11 °C. In this case, the isotherms over Europe have a meridional orientation.
The fact that Eurasia and North America face the Arctic basin as a broad front contributes to the deep penetration of cold air masses onto the continents throughout the year. Intense 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 high speed its movement, high moisture content and continuous low clouds.
In winter, the consequence of intense meridional circulation of air masses is the so-called “jumps” of temperatures, their large inter-day amplitude, especially in areas where cyclones are frequent: in northern Europe and Western Siberia, the Great Plains of North America.
IN cold period fall in the form of snow, a snow cover is formed, which protects the soil from deep freezing and creates a supply of moisture in the spring. The depth of the snow cover depends on the duration of its occurrence and the amount of precipitation. In Europe, stable snow cover on flat areas forms 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 snow cover is 30-35 cm, and in Transbaikalia - less than 20 cm. On the plains of Mongolia, in the center of the anticyclonic region, snow cover forms only in some years. The lack of snow, along with low winter air temperatures, causes the presence of permafrost, which is not observed anywhere else on the globe at these latitudes.
In North America, snow cover is negligible on the Great Plains. To the east of the plains, tropical air increasingly begins to take part in frontal processes; it aggravates frontal processes, which causes heavy snowfalls. In the Montreal area, snow cover lasts up to four months, and its height reaches 90 cm.
Summer in continental areas Eurasia is warm. The average July temperature is 18-22 °C. In the arid regions of south-eastern Europe and Central Asia The average air temperature in July reaches 24-28 °C.
In North America, continental air in summer is somewhat colder than in Asia and Europe. This is due to the smaller latitudinal extent of the continent, the large ruggedness of its northern part with bays and fjords, the abundance of large lakes, and the more intense development of cyclonic activity compared to the interior regions of Eurasia.
In the temperate zone, the annual precipitation on the flat continental areas varies from 300 to 800 mm; on the windward slopes of the Alps more than 2000 mm falls. Most of the precipitation falls in 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 decreases from north to south due to a decrease in the frequency of cyclones and an increase in dry air in this direction. In North America, a decrease in precipitation across the territory is observed, on the contrary, towards the west. Why do you think?
Most of the land in the continental temperate climate zone is occupied by mountain systems. These are the Alps, Carpathians, Altai, Sayans, Cordillera, Rocky Mountains etc. In mountainous areas, climatic conditions differ significantly from the climate of the plains. In summer, the air temperature in the mountains drops quickly with altitude. In winter, when cold air masses invade, the air temperature on the plains is often lower than in the mountains.
The influence of mountains on precipitation is great. Precipitation increases on windward slopes and at some distance in front of them, and decreases on leeward slopes. For example, differences in annual precipitation between western and eastern slopes Ural mountains in some places they reach 300 mm. In mountains, precipitation increases with altitude to a certain critical level. In the Alps the level the largest number precipitation occurs at altitudes 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 northeast China -5...-10°C. The average temperature of the warmest month ranges from 25-30 °C, with daily maximums exceeding 40-45 °C.
The most strongly continental climate in the air temperature regime is manifested in the southern regions of Mongolia and northern China, where the center of the Asian anticyclone is located in the winter season. Here the annual air temperature range is 35-40 °C.
Sharply continental climate in the subtropical zone for the high mountain regions of the Pamirs and Tibet, the altitude of which 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, the continental arid subtropical climate is formed in closed plateaus and in intermountain basins located between the Coast 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. A temperature of +56.7 °C was recorded in Death Valley!
Humid subtropical climate characteristic of the eastern coasts of 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 humid subtropics long and hot, with temperatures similar to those in the tropics. The average temperature of the warmest month exceeds +27 °C, and the maximum is +38 °C. 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, average annual precipitation amounts range from 750 to 2000 mm, and the distribution of precipitation across seasons is quite uniform. In winter, rain 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, characteristic of the monsoon circulation of East Asia. Hurricanes (or typhoons) occur in late summer and fall, especially in the Northern Hemisphere.
Subtropical climate with dry summers, typical for the western coasts of continents north and south of the tropics. In Southern Europe and North Africa, such climatic conditions are typical for the coasts Mediterranean Sea, which was the reason to call this climate also Mediterranean. Similar climate in southern California, central regions Chile, southernmost Africa and parts of southern Australia. All these areas have hot summers and mild winters. As in the humid subtropics, there are occasional frosts in winter. In inland areas, summer temperatures are significantly higher than on the coasts, and often the same as in tropical deserts. In general, clear weather prevails. In summer, there are often fogs on the coasts near which ocean currents pass. For example, in San Francisco, summers are cool, foggy, and the most warm month- 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 downdrafts of air over the oceans cause dryness summer season. The average annual precipitation in a subtropical climate ranges from 380 to 900 mm and reaches maximum values on the coasts and mountain slopes. In summer, there is usually not enough rainfall for normal tree growth, and therefore a specific type of evergreen develops there. shrub vegetation, known as maquis, chaparral, mali, macchia and fynbos.
Equatorial climate zone
Equatorial climate type distributed in equatorial latitudes in the Amazon basins South America and Congo in Africa, on the Malacca Peninsula and on the islands of Southeast Asia. Usually the average annual temperature is about +26 °C. Due to the high midday position of the Sun above the horizon and the same length of day throughout the year, seasonal temperature fluctuations are small. Humid air, cloudy and thick vegetation cover prevent night cooling and maintain maximum daytime temperatures below +37 °C, lower than at higher latitudes. The average annual precipitation in the humid tropics ranges from 1500 to 3000 mm and is usually evenly distributed over the seasons. Precipitation is mainly associated with the Intertropical 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 maximum precipitation during the year, separated by drier periods. Every day, thousands of thunderstorms roll over the humid tropics. In between, the sun shines in full force.
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