Climate message. §fourteen. Climatic zones and regions of the Earth. Cold climate zones

Introduction

Introduction……………………………………………………………………………………………3

Climate and its types…………………………………………………………………………………4

Climate-forming factors…………………………………………………………………….6

Anthropogenic impact on climate change……………………………………………..8

Non-climatic factors and their impact on climate change…………………………..11

The impact of climate on humans…………………………………………………………………….12

Bibliographic list………………………………………………………………………………...14

Today, humanity is on the verge of an ecological crisis, i.e., such a state of the environment, ĸᴏᴛᴏᴩᴏᴇ, due to the changes that have occurred in it, turns out to be unsuitable for human life. The expected crisis is anthropogenic in origin, as changes in the Earth's biosphere, associated with human impact on it, lead to it.

The natural wealth of the planet is divided into non-renewable and renewable. Non-renewable, for example, include minerals, the reserves of which are limited. The trend in changes in renewable natural resources can be seen in the example of the forest. Today, about a third of the land is covered with forest, while in prehistoric times at least 70% was occupied by it.

The destruction of forests, first of all, sharply violates the water regime of the planet. Rivers become shallow, their bottom is covered with silt, and this, in turn, leads to the destruction of spawning grounds and a decrease in the number of fish. The reserves of groundwater are reduced, a lack of moisture in the soil is created. Melt water and rain streams wash away, and winds, not restrained by a forest barrier, weather the soil layer. The result is soil erosion. Wood, branches, bark, litter accumulate mineral plant nutrients. The destruction of forests leads to the washing out of these soil elements and, consequently, a drop in its fertility. With deforestation, the birds, animals, insects-entomophagous inhabiting them perish. As a result, pests of agricultural crops reproduce freely.

The forest cleans the air from toxic pollution, in particular, it traps radioactive fallout and prevents their further spread, i.e. deforestation eliminates an important component of air self-purification. Finally, the destruction of forests on the slopes of the mountains is a significant cause of the formation of ravines and mudflows.

Industrial waste, pesticides used to control pests of agricultural crops, radioactive substances, in particular, in the testing of nuclear and thermonuclear weapons, pollute the natural environment. So, only cars in large cities emit about 50 million m 3 of carbon monoxide into the atmosphere per year, in addition, each car emits about 1 kg of lead annually. It was found that in the body of people living near major highways, the lead content is increased.

Human activity changes the structure of the earth's surface, alienating the territory occupied by natural biogeocenoses for agricultural land, the construction of settlements, communications, reservoirs. To date, about 20% of the land has been converted in this way.

The negative impacts include unregulated fishing for fish, mammals, invertebrates, algae, changes in the chemical composition of water, air, and soil as a result of industrial, transport, and agricultural waste discharges.

Climate (ancient Greek κλίμα (genus p. κλίματος) - slope) 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. By climate it is customary to understand the average value of weather over a long period of time (of the order of several decades), that is, climate is the average weather. Τᴀᴋᴎᴍ ᴏϬᴩᴀᴈᴏᴍ, weather is an instantaneous state of some characteristics (temperature, humidity, atmospheric pressure). The deviation of the weather from the climatic 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 the characteristics of the atmosphere over a long period of time of the order of ten years is needed.

Climatic zones and climate types vary significantly in latitude, ranging from the equatorial zone to the polar zone, but climatic zones are not the only factor, the proximity of the sea, the atmospheric circulation system and altitude above sea level also have an important influence.

Brief description of the climates of Russia:

· Arctic: January t −24…-30, summer t +2…+5. Precipitation - 200-300 mm.

· Subarctic: (up to 60 degrees north latitude). summer t +4…+12. Precipitation 200-400 mm.

In Russia and on the territory of the former USSR, the classification of climate types was used, created in 1956 by the famous Soviet climatologist B.P. Alisov. This classification takes into account the features of atmospheric circulation. According to this classification, four basic climatic zones are distinguished 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 are transitional belts - 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, the climate of the western and the climate of the eastern coasts.

equatorial belt

Equatorial climate

Subequatorial belt

Tropical monsoon climate

Monsoon climate on tropical plateaus

Tropical belt

Tropical dry climate

Tropical humid climate

Subtropical belt

Mediterranean climate

Subtropical continental climate

Subtropical monsoon climate

The climate of the high subtropical highlands

Subtropical climate of the oceans

· Temperate zone

temperate maritime climate

temperate continental climate

Moderate continental climate

Moderate sharply 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. Köppen (1846-1940) is widespread in the world. It is based on the temperature regime and the degree of moisture. According to this classification, eight climatic zones with eleven types of climate are distinguished. Each type has precise parameters for temperature values, the amount of winter and summer precipitation.

Also in climatology, the following concepts related to climate characteristics are used:

Continental climate

Maritime climate

Alpine climate

Arid climate

Humid climate

Nival climate

solar climate

Monsoon climate

· Passat climate

The country is located in middle and high latitudes, which is why there is a clear division into seasons. Atlantic air influences the European part. The weather there is milder than in the east. The polar ones receive the least sun, the maximum value is reached in the Western Ciscaucasia.

The territory of the country lies at once in four main climatic zones. Each of them has its own temperature and precipitation rates. From east to west, there is a transition from the monsoon climate to the continental one. The central part is characterized by a distinct delimitation of the seasons. In the south, the temperature rarely drops below 0˚C in winter.

Climatic zones and regions of Russia

Map of climatic zones and regions of Russia / Source: smart-poliv.ru

Air masses play a decisive role in the division into belts. Within them are climatic regions. Between themselves, they differ in temperature, amount of heat and moisture. Below is a brief description of the climatic zones of Russia, as well as the areas that they include.

arctic belt

It includes the coast of the Arctic Ocean. In winter, severe frost prevails, the average January temperature exceeds -30˚C. The western part is slightly warmer due to the air from the Atlantic. In winter, the polar night sets in.

The sun shines in the summer, but due to the small angle of incidence of the sun's rays and the reflective properties of the snow, heat does not linger near the surface. A lot of solar energy is spent on melting snow and ice, so the temperature regime of the summer period approaches zero. The Arctic belt is characterized by a small amount of precipitation, most of which falls in the form of snow. The following climatic regions are distinguished:

• Intraarctic;
• Siberian;
• Pacific;
• Atlantic.

The most severe is the Siberian region, the Atlantic is mild, but windy.

subarctic belt

It includes the territories of the Russian and West Siberian Plains, located mainly and forest-tundra. Winter temperatures increase from west to east. Summer rates average +10˚C, and even higher near the southern borders. Even in the warm season, there is a threat of frost. There is little precipitation, the main share falls on rains and sleet. Due to this, waterlogging is observed in the soil. In this climatic zone, the following areas are distinguished:

• Siberian;
• Pacific;
• Atlantic.

The lowest temperatures in the country were recorded in the Siberian region. The climate of the other two is moderated by cyclones.

Temperate zone

It includes most of the territory of Russia. Winters are snowy, sunlight reflects off the surface, causing the air to become very cold. In the summer, the amount of light and heat increases. In the temperate zone, there is a significant contrast between cold winters and warm summers. There are four main types of climate:

1) Temperate continental is in the western part of the country. Winters are not particularly cold thanks to the Atlantic air, and thaws often occur. The average summer temperature is +24˚C. The influence of cyclones causes a significant amount of precipitation in the summer.

2) Continental climate affects the territory of Western Siberia. Throughout the year, both arctic and tropical air penetrates into this zone. Winters are cold and dry, summers are hot. The influence of cyclones is weakening, so there is little precipitation.

3) Sharply continental climate dominates in Central Siberia. Throughout the territory there are very cold winters with little snow. Winter temperatures can reach -40˚C. In summer, the air warms up to +25˚C. Precipitation is scarce and falls as rain.

4) Monsoon type of climate prevails in the eastern part of the belt. In winter, continental air dominates here, and in summer - sea. Winter is snowy and cold. January figures are -30˚C. Summers are warm but humid, with frequent showers. The average July temperature exceeds +20˚C.

The following climatic regions are located within the temperate zone:

• Atlantic-Arctic;
• Atlantic-continental European (forest);
• Continental West Siberian northern and central;
• Continental East Siberian;
• Monsoon Far East;
• Pacific;
• Atlantic-continental European (steppe);
• Continental West Siberian southern;
• Continental Eastern European;
• Mountainous region of the Greater Caucasus;
• Mountain region of Altai and Sayan.

subtropical climate

It includes a small area of ​​the Black Sea coast. The mountains of the Caucasus do not allow air flow from the east, so it is warm in the Russian subtropics in winter. Summer is hot and long. Snow and rain fall all year round, there are no dry periods. In the subtropics of the Russian Federation, only one region is distinguished - the Black Sea.

Climatic zones of Russia

Map of climatic zones of Russia / Source: meridian-workwear.com

A climate zone is a territory in which the same climatic conditions prevail. The division arose due to uneven heating of the Earth's surface by the sun. There are four climatic zones on the territory of Russia:

• the first includes the southern regions of the country;
• the second includes the regions of the west, north-west, as well as Primorsky Krai;
• the third includes Siberia and the Far East;
• the fourth includes the Far North and Yakutia.

Along with them, there is a special zone that includes Chukotka and territories beyond the Arctic Circle.

The climate of the regions of Russia

Krasnodar region

The minimum January temperature is 0˚C, the soil does not freeze through. The fallen snow quickly melts away. Most of the precipitation falls in the spring, causing numerous floods. Summer temperatures average 30˚C, drought begins in the second half. Autumn is warm and long.

central Russia

Winter starts from the end of November and lasts until mid-March. Depending on the region, January temperatures range from -12˚C to -25˚C. A lot of snow falls, which melts only with the onset of thaws. Extremely low temperatures occur in January. February is remembered by winds, often hurricanes. Heavy snowfalls in the last few years occur at the beginning of March.

Nature comes to life in April, but positive temperatures are set only next month. In some regions, the threat of frost occurs in early June. Summer is warm and lasts 3 months. Cyclones bring thunderstorms and showers. Night frosts occur as early as September. There is a lot of rainfall this month. In October, a sharp cold snap occurs, foliage flies off the trees, it rains, sleet can fall.

Karelia

The climate is influenced by 3 neighboring seas, the weather is very changeable throughout the year. The minimum January temperature is -8˚C. A lot of snow falls. February weather is changeable: cold snaps are followed by thaws. Spring comes in April, the air warms up to + 10˚С during the day. Summer is short, really warm days are only in June and July. September is dry and sunny, but frosts are already occurring in some areas. The final cold weather sets in October.

Siberia

One of the largest and coldest regions of Russia. Winter is not snowy, but very cold. In remote areas, the thermometer shows more than -40˚C. Snowfalls and winds are rare. The snow melts in April, and in the region with heat comes only in June. Summer marks are + 20˚С, there is little precipitation. In September, calendar autumn begins, the air cools quickly. By October, the rains are replaced by snow.

Yakutia

The average monthly temperature in January is -35˚C, in the Verkhoyansk region the air cools down to -60˚C. Cold time lasts at least seven months. There is little rainfall, daylight hours last 5 hours. Beyond the Arctic Circle, the polar night begins. Spring is short, comes in May, summer lasts 2 months. During the white nights, the sun does not set for 20 hours. Already in August, a rapid cooling begins. By October, the rivers are covered with ice, and the snow stops melting.

Far East

The climate is varied, ranging from continental to monsoonal. The approximate winter temperature is -24˚C, there is a lot of snow. There is little rainfall in spring. Summer is hot, with high humidity, August is considered a period of prolonged rains. Fog dominates the Kuriles, white nights begin in Magadan. The beginning of autumn is warm but rainy. The thermometer marks in mid-October show -14˚C. A month later, winter frosts set in.

Most of the country lies in the temperate zone, some territories have their own climatic features. The lack of heat is felt in almost all belts. The climate has a serious impact on human activities, and it must be taken into account in agriculture, construction, and transport.

Climate (from the Greek klíma, genitive case klímatos, literally - slope; it means the slope of the earth's surface to the sun's rays)

long-term weather regime, characteristic of a particular area on Earth and being one of its geographical characteristics. In this case, the multi-year regime is understood as the totality of all weather conditions in a given area over a period of several decades; typical annual change of these conditions and possible deviations from it in individual years; combinations of weather conditions characteristic of its various anomalies (droughts, rainy periods, cooling, etc.). Around the middle of the 20th century The concept of aerodynamics, previously applied only to conditions near the earth's surface, was also extended to the high layers of the atmosphere.

Conditions for the formation and evolution of climate. The main characteristics of K. To reveal the features of the climate, both typical and rarely observed, long-term series of meteorological observations are needed. In temperate latitudes, 25-50-year series are used; in the tropics, their duration may be shorter; sometimes (for example, for Antarctica, high layers of the atmosphere) it is necessary to confine oneself to shorter observations, given that subsequent experience may clarify preliminary ideas.

In the study of oceanic oceans, in addition to observations on islands, they use information obtained at different times on board ships in a given section of the water area and regular observations on weather ships.

Climatic characteristics are statistical conclusions from long-term observation series, primarily over the following main 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, the visibility range, the temperature of the upper layers of soil and reservoirs, the evaporation of water from the earth's surface into the atmosphere, the height and condition of the snow cover, and various atm. phenomena and ground-based hydrometeors (dew, ice, fog, thunderstorms, snowstorms, etc.). In the 20th century The climatic indicators included characteristics of the elements of the heat balance of the earth's surface, such as total solar radiation, radiation balance, heat exchange between the earth's surface and the atmosphere, and heat consumption for evaporation.

K.'s characteristics of the free atmosphere (see. Aeroclimatology ) refer mainly to atmospheric pressure, wind, temperature, and air humidity; they are joined by data on radiation.

Long-term average values ​​of meteorological elements (annual, seasonal, monthly, daily, etc.), their sums, frequencies, and others are called climatic norms; the corresponding values ​​for individual days, months, years, etc. are considered as a deviation from these norms. To characterize climate, complex indicators are also used, i.e., functions of several elements: various coefficients, factors, indices (for example, continentality, aridity, moisture content), etc.

Special indicators of temperature are used in the applied branches of climatology (for example, the sum of the temperatures of the growing season in agroclimatology, effective temperatures in bioclimatology and technical climatology, degree days in calculations of heating systems, and so on).

In the 20th century ideas arose about the microclimate, the climate of the surface layer of air, the local climate, and others, as well as the macroclimate—the climate of territories on a planetary scale. There are also K. soil" and "K. plants" (phytoclimate), characterizing the habitat of plants. The term "urban climate" has also gained wide popularity, since the modern big city significantly affects its K.

The main processes that shape climate change Climatic conditions on Earth are created as a result of the following main interconnected cycles of geophysical processes on a global scale: heat circulation, moisture circulation, and general circulation of the atmosphere.

Moisture circulation consists in the evaporation of water into the atmosphere from water bodies and land, including plant transpiration; in the transfer of water vapor to the high layers of the atmosphere (see Convection) , as well as air currents of the general circulation of the atmosphere; in the condensation of water vapor in the form of clouds and fogs; in the transfer of clouds by air currents and in the precipitation from them; in the runoff of precipitation and in their new evaporation, etc. (see Moisture circulation).

The general circulation of the atmosphere creates mainly the wind regime. With the transfer of air masses by general circulation, the global transfer of heat and moisture is associated. Local atmospheric circulations (breezes, mountain-valley winds, etc.) create air transfer only over limited areas of the earth's surface, which is superimposed on the general circulation and affects the climatic conditions in these areas ( see Atmospheric circulation).

Influence of Geographical Factors on K. Climate-forming processes occur under the influence of a number of geographical factors, the main of which are: 1) Geographic latitude, which determines zonality and seasonality in the distribution of solar radiation coming to the Earth, and with it air temperature, atmospheric pressure, etc.; latitude also affects wind conditions directly, since the deflecting force of the Earth's rotation depends on it. 2) Height above sea level. Climatic conditions in the free atmosphere and in the mountains vary with altitude. Relatively small differences in height, measured in hundreds and thousands m, are equivalent in their influence on k. to latitudinal distances of thousands km. In this regard, altitudinal climatic zones can be traced in the mountains (see Altitudinal zonality). 3) Distribution of land and sea. Due to the different conditions for the propagation of heat in the upper layers of the soil and water, and due to their different absorbing capacities, differences are created between the climates of the continents and oceans. The general circulation of the atmosphere then leads to the fact that the conditions of maritime oceans spread with air currents into the depths of the continents, while the conditions of continental oceans spread to neighboring parts of the oceans. 4) Orography. Mountain ranges and massifs with different slope exposures create large disturbances in the distribution of air currents, air temperature, cloudiness, precipitation, etc. 5) Ocean currents. Warm currents, falling into high latitudes, give off heat to the atmosphere; cold currents, moving towards low latitudes, cool the atmosphere. Currents affect both moisture circulation, promoting or hindering the formation of clouds and fogs, and atmospheric circulation, since the latter depends on temperature conditions. 6) The nature of the soil, especially its reflectivity (albedo) and humidity. 7) Vegetation cover to a certain extent affects the absorption and return of radiation, moisture and wind, 8) Snow and ice cover. Seasonal snow cover over land, sea ice, permanent ice and snow cover in areas such as Greenland and Antarctica, firn fields and glaciers in the mountains significantly affect the temperature regime, wind conditions, cloudiness, and moisture. 9) The composition of the air. Naturally, it does not change significantly over short periods, except for the sporadic influences of volcanic eruptions or forest fires. However, in industrial areas there is an increase in the content of carbon dioxide from fuel combustion and air pollution by gas and aerosol waste from production and transport.

Climate and people. Types K. and their distribution around the globe, have the most significant impact on the water regime, soil, vegetation and wildlife, as well as on the distribution and productivity of agricultural crops. cultures. K. to a certain extent affects the resettlement, location of industry, living conditions and health of the population. Therefore, a correct account of the peculiarities and influences of climate is necessary not only in agriculture, but also in the location, planning, construction, and operation of hydropower and industrial facilities, in urban planning, in the transport network, and also in public health (resort network, climate therapy, and the fight against epidemics). , social hygiene), tourism, sports. The study of climatic conditions, both in general and from the point of view of certain needs of the national economy, and the generalization and dissemination of data on climate control for the purpose of their practical use in the USSR, are carried out by the institutions of the USSR Hydrometeorological Service.

Mankind has not yet been able to significantly influence climate by directly changing the physical mechanisms of climate-forming processes. The active physical and chemical impact of man on the processes of cloud formation and precipitation is already a reality, but it has no climatic significance due to its spatial limitations. The industrial activity of human society leads to an increase in the content of carbon dioxide, industrial gases and aerosol impurities in the air. This affects not only the living conditions and health of people, but also the absorption of radiation in the atmosphere and thus the air temperature. The influx of heat into the atmosphere is also constantly increasing due to the combustion of fuel. These anthropogenic changes in K. are especially noticeable in large cities; on a global scale, they are still insignificant. But in the near future we can expect their significant increase. In addition, by influencing one or another of the geographical factors of climate change, that is, by changing the environment in which climate-forming processes take place, people, without knowing it or taking it into account, have long worsened climate change by irrational deforestation, predatory plowing of land . On the contrary, the implementation of rational irrigation measures and the creation of oases in the desert improved the K. of the respective regions. The task of a conscious, targeted improvement of climate is set mainly in relation to the microclimate and local climate. A purposeful expansion of the impact on the soil and vegetation (planting forest belts, draining and irrigating the territory) seems to be a real and safe way of such improvement.

Climate change. Studies of sedimentary deposits, fossil remains of flora and fauna, the radioactivity of rocks, and other studies show that the Earth's K. has changed significantly in different epochs. During the last hundreds of millions of years (before the Anthropogen), the Earth was apparently warmer than at present: the temperature in the tropics was close to modern, and in temperate and high latitudes it was much higher than modern. At the beginning of the Paleogene (about 70 million years ago), the temperature contrasts between the equatorial and subpolar regions began to increase, but before the beginning of the Anthropogen they were less than the current ones. In the Anthropogen, the temperature in high latitudes dropped sharply and polar glaciations arose. The last reduction of glaciers in the Northern Hemisphere apparently ended about 10 thousand years ago, after which the permanent ice cover remained mainly in the Arctic Ocean, in Greenland and other Arctic islands, and in the Southern Hemisphere - in Antarctica.

To characterize K. for the last few thousand years, there is extensive material obtained using paleographic research methods (dendrochronology, palynological analysis, etc.), based on the study of archaeological data, folklore and literary monuments, and, at a later time, chronicle evidence. It can be concluded that over the past 5,000 years, the K. of Europe and the regions close to it (and probably the entire globe) has fluctuated within relatively narrow limits. Dry and warm periods were replaced several times by more humid and cool ones. Approximately 500 years BC. e. precipitation increased markedly and K. became cooler. At the beginning of N. e. it was similar to modern. In the 12th-13th centuries. K. was softer and drier than at the beginning of AD. e., but in the 15-16 centuries. again there was a significant cooling and the ice cover of the seas increased. Over the past 3 centuries, an ever-increasing material of instrumental meteorological observations has been accumulated, which have gained global distribution. From the 17th to the middle of the 19th centuries. K. remained cold wet, glaciers were advancing. From the 2nd half of the 19th century. a new warming began, especially strong in the Arctic, but covering almost the entire globe. This so-called modern warming continued until the middle of the 20th century. Against the background of fluctuations in cosmos, covering hundreds of years, there were short-term fluctuations with smaller amplitudes. Changes To. have, thus, rhythmic, oscillatory character.

The climatic regime that prevailed before the Anthropogene - warm, with small temperature contrasts and the absence of polar glaciations - was stable. On the other hand, the Anthropogenic climate and modern climate with glaciations, their pulsations, and sharp fluctuations in atmospheric conditions are unstable. According to the conclusions of M. I. Budyko, a very slight increase in the average temperatures of the earth's surface and atmosphere can lead to a decrease in polar glaciations, and the resulting change in the reflectivity (albedo) of the Earth - to further warming of their reduction in ice until their complete disappearance.

Climates of the Earth. Climatic conditions on Earth are closely dependent on geographic latitude. In this regard, even in ancient times, there was an idea of ​​\u200b\u200bclimatic (thermal) zones, the boundaries of which coincide with the tropics and the polar circles. In the tropical zone (between the northern and southern tropics), the Sun is at its zenith twice a year; the length of the daytime at the equator throughout the year is 12 h, and inside the tropics it ranges from 11 to 13 h. In the temperate zones (between the tropics and the polar circles), the sun rises and sets every day, but never at its zenith. Its noon height in summer is much greater than in winter, as is the length of daylight hours, and these seasonal differences increase as one approaches the poles. Beyond the polar circles, the Sun does not set in summer, and in winter it does not rise for a longer time, the greater the latitude of the place. At the poles, the year is divided into six-month days and nights.

The features of the visible motion of the Sun determine the influx of solar radiation to the upper boundary of the atmosphere at different latitudes and at different moments and seasons (the so-called solar climate). In the tropical zone, the influx of solar radiation to the boundary of the atmosphere has an annual variation with a small amplitude and two maxima during the year. In temperate zones, the influx of solar radiation to a horizontal surface at the boundary of the atmosphere in summer differs relatively little from the influx in the tropics: the lower altitude of the sun is compensated by the increased length of the day. But in winter, the influx of radiation decreases rapidly with latitude. In polar latitudes, with a long continuous day, the summer influx of radiation is also large; on the day of the summer solstice, the pole receives at the boundary of the atmosphere even more radiation to the horizontal surface than the equator. But in the winter half-year, there is no influx of radiation at the Pole at all. Thus, the influx of solar radiation to the boundary of the atmosphere depends only on the geographical latitude and on the season and has a strict zonality. Within the atmosphere, solar radiation experiences non-zonal influences due to different contents of water vapor and dust, different cloudiness, and other features of the gaseous and colloidal state of the atmosphere. A reflection of these influences is the complex distribution of the amounts of radiation entering the Earth's surface. Numerous geographical factors of climate (the distribution of land and sea, orographic features, sea currents, etc.) also have a non-zonal character. Therefore, in the complex distribution of climatic characteristics near the earth's surface, zonality is only a background that appears more or less clearly through non-zonal influences.

The basis of the climatic zoning of the Earth is the division of territories into belts, zones and regions with more or less uniform climatic conditions. The boundaries of climatic zones and zones not only do not coincide with latitudinal circles, but also do not always go around the globe (zones in such cases are broken into areas that do not interlock with each other). Zoning can be carried out either according to climatic characteristics proper (for example, according to the distribution of average air temperatures and the amount of precipitation in W. Koeppen), or according to other sets of climatic characteristics, as well as according to the features of the general circulation of the atmosphere, which are associated with climate types (for example, classification B.P. Alisov), or by the nature of geographical landscapes determined by climate (classification by L.S. Berg). The following characterization of the Earth's climates basically corresponds to the zoning of B.P. Alisov (1952).

The profound influence of the distribution of land and sea on climate is already evident from a comparison of the conditions of the northern and southern hemispheres. The main land masses are concentrated in the Northern Hemisphere and therefore its climatic conditions are more continental than in the Southern. The average surface air temperature in the Northern Hemisphere in January is 8 °С, in July 22 °С; in the South, respectively, 17 ° C and 10 ° C. For the entire globe, the average temperature is 14°C (12°C in January, 16°C in July). The warmest parallel of the Earth - the thermal equator with a temperature of 27 ° C - coincides with the geographic equator only in January. In July, it shifts to 20° north latitude, and its average annual position is about 10° north latitude. From the thermal equator to the poles, the temperature drops by an average of 0.5-0.6 ° C for each degree of latitude (very slowly in the tropics, faster in extratropical latitudes). At the same time, inside the continents, the air temperature is higher in summer and lower in winter than over the oceans, especially in temperate latitudes. This does not apply to the climate over the ice plateaus of Greenland and Antarctica, where the air is much colder all year round than over the adjacent oceans (average annual air temperatures drop to -35 °C, -45 °C).

The average annual precipitation is greatest in equatorial latitudes (1500-1800 mm), to the subtropics, they decrease to 800 mm, in temperate latitudes again increase to 900-1200 mm and sharply decrease in the polar regions (up to 100 mm or less).

The equatorial climate embraces a band of low atmospheric pressure (the so-called equatorial depression) that extends 5–10° north and south of the equator. It is distinguished by a very uniform temperature regime with high air temperatures throughout the year (usually fluctuating between 24 ° C and 28 ° C, and the temperature amplitudes on land do not exceed 5 ° C, and at sea can be less than 1 ° C). Humidity is constantly high, the annual amount of precipitation varies from 1 to 3 thousand km. mm per year, but in some places it reaches 6-10 thousand on land. mm. Precipitation usually falls in the form of showers, and, especially in the intertropical convergence zone that separates the trade winds of the two hemispheres, they are usually evenly distributed throughout the year. Cloudiness is significant. The predominant natural landscapes of the land are moist equatorial forests.

On both sides of the equatorial depression, in areas of high atmospheric pressure, in the tropics above the oceans, a trade wind climate prevails with a stable regime of easterly winds (trade winds), moderate cloudiness and fairly dry weather. The average temperatures of the summer months are 20-27 °С, in the winter months the temperature drops to 10-15 °С. The annual amount of precipitation is about 500 mm, their number sharply increases on the slopes of mountainous islands facing the trade winds, and with relatively rare passages of tropical cyclones.

The areas of oceanic trade winds correspond on land to territories with a tropical desert climate, characterized by exceptionally hot summers (the average temperature of the warmest month in the Northern Hemisphere is about 40 ° C, in Australia up to 34 ° C). The absolute maximum temperature in North Africa and the interior of California is 57-58 ° C, in Australia - up to 55 ° C (the highest air temperatures on Earth). Average temperatures of the winter months from 10 to 15 °C. Daily temperature amplitudes are large (in some places over 40 °C). There is little precipitation (usually less than 250 mm, often less than 100 mm in year).

In some areas of the tropics (Equatorial Africa, South and Southeast Asia, Northern Australia), the climate of the trade winds is replaced by the climate of tropical monsoons. The intratropical convergence zone shifts here in summer far from the equator, and instead of the easterly trade winds between it and the equator, a westerly air transport (summer monsoon) arises, with which most of the precipitation is associated. On average, they fall almost as much as in the equatorial climate (in Calcutta, for example, 1630 mm per year, of which 1180 mm falls during the 4 months of the summer monsoon). On the slopes of the mountains facing the summer monsoon, precipitation is record-breaking for the respective regions, and in the North-East of India (Cherrapunji) their maximum amount on the globe (on average about 12 thousand tons) falls. mm in year). Summers are hot (average air temperatures are above 30 °C), and the warmest month usually precedes the onset of the summer monsoon. In the zone of tropical monsoons, in East Africa and in South-West Asia, the highest average annual temperatures on the globe (30-32 ° C) are also observed. Winters are cold in some areas. The average January temperature is 25°C in Madras, 16°C in Varanasi and only 3°C in Shanghai.

In the western parts of the continents in subtropical latitudes (25-40 ° north latitude and south latitude), the climate is characterized by high atmospheric pressure in summer (subtropical anticyclones) and cyclonic activity in winter, when anticyclones move somewhat towards the equator. Under these conditions, a Mediterranean climate is formed, which is observed, in addition to the Mediterranean, on the southern coast of Crimea, as well as in western California, in southern Africa, and in southwestern Australia. With hot, cloudy and dry summers, there are cool and rainy winters. Precipitation is usually low and some areas with this climate are semi-arid. Temperatures in summer 20-25 °С, in winter 5-10 °С, annual precipitation is usually 400-600 mm.

Inside the continents in subtropical latitudes, increased atmospheric pressure prevails in winter and summer. Therefore, the climate of dry subtropics is formed here, hot and slightly cloudy in summer, cool in winter. Summer temperatures, for example, in Turkmenistan reach up to 50 °C on some days, and frosts down to -10, -20 °C are possible in winter. The annual amount of precipitation in some places is only 120 mm.

In the high uplands of Asia (Pamir, Tibet), a cold desert climate is formed with cool summers, very cold winters and poor rainfall. In Murgab in the Pamirs, for example, in July 14 ° C, in January -18 ° C, precipitation is about 80 mm in year.

In the eastern parts of the continents in subtropical latitudes, a monsoonal subtropical climate is formed (East China, Southeast USA, countries of the Paraná river basin in South America). The temperature conditions here are close to areas with a Mediterranean climate, but precipitation is more abundant and falls mainly in summer, during the oceanic monsoon (for example, in Beijing out of 640 mm precipitation per year 260 mm falls in July and only 2 mm in December).

For temperate latitudes, intense cyclonic activity is very characteristic, leading to frequent and strong changes in air pressure and temperature. Westerly winds prevail (especially over the oceans and in the Southern Hemisphere). Transitional seasons (autumn, spring) are long and well expressed.

In the western parts of the continents (mainly Eurasia and North America), a maritime climate prevails with cool summers, warm (for these latitudes) winters, moderate rainfall (for example, in Paris in July 18 ° C, in January 2 ° C, precipitation 490 mm per year) without stable snow cover. Precipitation increases sharply on the windward slopes of the mountains. So, in Bergen (at the western foothills of the Scandinavian mountains), precipitation is over 2500 mm per year, and in Stockholm (east of the Scandinavian mountains) - only 540 mm. The effect of orography on precipitation is even more pronounced in North America with its meridional ridges. On the western slopes of the Cascade Mountains, 3,000 to 6,000 rain falls in places. mm, while behind the ridges the amount of precipitation decreases to 500 mm and below.

The inland climate of temperate latitudes in Eurasia and North America is characterized by a more or less stable regime of high air pressure, especially in winter, with warm summers and cold winters with stable snow cover. The annual temperature amplitudes are large and grow deeper into the continents (mainly due to the increase in the severity of winters). For example, in Moscow in July 17°С, in January -10°С, precipitation is about 600 mm in year; in Novosibirsk in July 19°С, in January -19°С, precipitation 410 mm per year (maximum rainfall everywhere in summer). In the southern part of the temperate latitudes of the interior regions of Eurasia, the aridity of the climate increases, steppe, semi-desert and desert landscapes are formed, and the snow cover is unstable. The most continental climate is in the northeastern regions of Eurasia. In Yakutia, the region of Verkhoyansk - Oymyakon is one of the winter poles of cold in the Northern Hemisphere. The average temperature in January drops here to -50°С, and the absolute minimum is about -70°С. In the mountains and high plateaus of the inner parts of the continents of the Northern Hemisphere, winters are very severe and have little snow, anticyclonic weather prevails, summers are hot, precipitation is relatively low and falls mainly in summer (for example, in Ulaanbaatar in July 17 ° C, in January -24 ° C , precipitation 240 mm in year). In the Southern Hemisphere, due to the limited area of ​​the continents at the corresponding latitudes, the inland climate did not develop.

The monsoon climate of temperate latitudes is formed on the eastern outskirts of Eurasia. It is characterized by cloudy and cold winters with prevailing northwest winds, warm or moderately warm summers with southeast and south winds, and sufficient or even heavy summer precipitation (for example, in Khabarovsk in July 23°С, in January -20°С, precipitation 560 mm per year, of which only 74 mm falls in the cold half of the year). In Japan and Kamchatka, the winter is much milder, there is a lot of precipitation both in winter and in summer; on Kamchatka, Sakhalin and the island of Hokkaido, a high snow cover forms.

The climate of the Subarctic is formed on the northern outskirts of Eurasia and North America. Winters are long and severe, the average temperature of the warmest month is not higher than 12 ° C, precipitation is less than 300 mm, and in the North-East of Siberia even less than 100 mm in year. During cold summers and permafrost, even slight precipitation in many areas creates excessive moisture and waterlogging of the soil. In the Southern Hemisphere, a similar climate is developed only on the subantarctic islands and on Graham Land.

Over the oceans of temperate and subpolar latitudes in both hemispheres, intense cyclonic activity with windy cloudy weather and heavy precipitation prevails.

The climate of the Arctic Basin is severe, the average monthly temperatures vary from 0 °С in summer to -40 °С in winter, on the Greenland plateau from -15 to -50 °С, and the absolute minimum is close to -70 °С. The average annual air temperature is below -30 ° C, there is little precipitation (in most parts of Greenland, less than 100 mm in year). The Atlantic regions of the European Arctic are characterized by a relatively mild and humid climate, because warm air masses from the Atlantic Ocean often penetrate here (on Svalbard in January -16 ° C, in July 5 ° C, precipitation is about 320 mm in year); even at the North Pole, sharp warming is possible at times. In the Asian-American sector of the Arctic, the climate is more severe.

The climate of Antarctica is the most severe on Earth. Strong winds blow on the coasts, associated with the continuous passage of cyclones over the surrounding ocean and with the outflow of cold air from the central regions of the mainland along the slopes of the ice sheet. The average temperature in Mirny is -2 °С in January and December, -18 °С in August and September. Precipitation from 300 to 700 mm in year. Inside East Antarctica, on a high ice plateau, high atmospheric pressure almost constantly dominates, the winds are weak, and there is little cloudiness. The average temperature in summer is about -30 °С, in winter it is about -70 °С. The absolute minimum at Vostok station is close to -90 °C (the cold pole of the entire globe). Precipitation less than 100 mm in year. In West Antarctica and at the South Pole, the climate is somewhat milder.

Lit.: Climatology course, parts 1-3, L., 1952-54; Atlas of the heat balance of the globe, ed. M. I. Budyko. Moscow, 1963. Berg L. S., Fundamentals of climatology, 2nd ed., L., 1938; his own, Climate and Life, 2nd ed., M., 1947; Brooks, K., Climates of the past, trans. from English, M., 1952; Budyko M.I., Climate and life, L., 1971; Voeikov A.I., Climates of the globe, especially Russia, Izbr. soch., v. 1, M. - L., 1948; Geiger P., Climate of the surface layer of air, trans. from English, M., 1960; Guterman I. G., Wind distribution over the northern hemisphere, L., 1965; Drozdov OA, Fundamentals of climatological processing of meteorological observations, L., 1956; Drozdov O. A., Grigorieva A. S., Moisture circulation in the atmosphere, L, 1963; Keppen V., Fundamentals of climatology, trans. from German., M., 1938; The climate of the USSR, c. 1-8, L., 1958-63; Methods of climatological processing, L., 1956; Microclimate of the USSR, L., 1967; Sapozhnikova S. A., Microclimate and local climate, L., 1950; Reference book on the climate of the USSR, c. 1-34, L., 1964-70; Bluthgen J., Allgemeine Klimageographie, 2 Aufl., B., 1966; Handbuch der Klimatologie. Hrsg. von W. Köppen and R. Geiger, Bd 1-5, B., 1930-36; Hann J., Handbuch der Klimatologie, 3 Aufl., Bd 1-3, Stuttg., 1908-11; World survey of climatology, ed. N. E. Landsberg, v. 1-15 Amst. - L. - N. Y., 1969.

Climate is the long-term weather pattern characteristic of a given area.

The climate influences the regime of rivers, the formation of various types of soils, vegetation and wildlife. So, in areas where the earth's surface receives a lot of heat and moisture, moist evergreen forests grow. Areas located near the tropics receive almost as much heat as at the equator, and much less moisture, so they are covered with sparse desert vegetation. Most of our country is occupied by coniferous forests, which have adapted to the harsh climate: cold and long winters, short and moderately warm summers, and average moisture.

Climate formation depends on many factors, primarily on geographical location. The latitude of the place determines the angle of incidence of the sun's rays and, accordingly, the amount of heat coming from the sun. The amount of heat also depends on the nature of the underlying surface and on the distribution of land and water. Water, as you know, slowly heats up, but also slowly cools down. Land, on the other hand, heats up quickly and cools down just as quickly. As a result, different weather regimes are formed over the water surface and over land.

Table 3

From this table it can be seen that Bantry on the west coast of Ireland, which is under the direct influence of the Atlantic Ocean, has an average temperature of the warmest month of 15.2 ° C, and the coldest - 7.1 ° C, i.e. its annual amplitude is 8, 1°C. With distance from the ocean, the average temperature of the warmest month rises and the coldest month decreases, i.e., the amplitude of annual temperatures increases. In Nerchinsk, it reaches 53.2 °C.

The relief has a great influence on the climate: mountain ranges and hollows, plains, river valleys, ravines create special climate conditions. Mountains are most often climatic divisions.

Influence the climate and sea currents. Warm currents carry a huge amount of heat from low latitudes to higher latitudes, cold currents carry cold from higher latitudes to low latitudes. In places washed by warm currents, the annual air temperature is 5-10 °C higher than at the same latitudes washed by cold currents.

Thus, the climate of each territory depends on the latitude of the place, the underlying surface, sea currents, relief and the height of the place above sea level.

The Russian scientist B.P. Alisov developed a classification of the climates of the globe. It is based on the types of air masses, their formation and change during movement under the influence of the underlying surface.

climatic zones.

Depending on the prevailing climate, the following climatic zones are distinguished: equatorial, two tropical, two temperate, two polar (Arctic, Antarctic) and transitional - two subequatorial, two subtropical and two subpolar (subarctic and subantarctic).

The equatorial belt covers the basins of the Congo and Amazon rivers, the coast of the Gulf of Guinea, and the Sunda Islands. The high position of the sun throughout the year causes a strong heating of the surface. Average annual temperatures here are from 25 to 28 °C. In the daytime, the air temperature rarely rises to 30 ° C, but the relative humidity remains high - 70-90%. Heated air, saturated with water vapor, rises under conditions of reduced pressure. Cumulus clouds appear in the sky, which cover the entire sky by noon. The air continues to rise, cumulus clouds turning into cumulonimbus, from which heavy rain showers fall in the afternoon. In this belt, the annual rainfall exceeds 2000 mm. There are places where their number increases to 5000 mm. Precipitation is evenly distributed throughout the year.

High temperatures throughout the year, a large amount of precipitation create conditions for the development of rich vegetation - humid equatorial forests.

The subequatorial belt occupies vast spaces - the Brazilian Highlands in South America, Central Africa to the north and east of the Congo Basin, most of the Hindustan and Indochina peninsulas, as well as Northern Australia.

The most characteristic feature of the climate of this belt is the change of air masses by seasons: in summer the whole area is occupied by equatorial air, in winter - by tropical air. As a result, two seasons are distinguished - wet (summer) and dry (winter). In the summer season, the weather is not much different from the equatorial one. Warm and humid air rises, which creates conditions for the formation of clouds and heavy rainfall. It is in this belt that the places with the greatest amount of precipitation are located (northeast India and the Hawaiian Islands). In winter, conditions change dramatically, dry tropical air prevails, and dry weather sets in. The grasses are burning and the trees are shedding their leaves. Most of the territories of the subequatorial belt are occupied by the zone of savannas and light forests.

The tropical belt is located on both sides of the tropics, both on the oceans and on the continents. Tropical air dominates here all year round. In conditions of high pressure and low cloudiness, it is characterized by high temperatures. The average temperature of the warmest month exceeds 30°C, and on some days it rises to 50–55°C.

There is little precipitation in most of the territory (less than 200 mm), here are the greatest deserts in the world - the Sahara, the Western Australian, the desert of the Arabian Peninsula.

But not everywhere in the tropical zones the climate is arid. On the eastern coasts of the continents, where the trade winds blow from the oceans, there is a lot of precipitation (the Greater Antilles, the east coast of Brazil, the east coast of Africa). The climate of these areas is not much different from the equatorial one, although the annual temperature fluctuations are significant, since there is a great difference in the height of the sun over the seasons. Due to the high rainfall and high temperatures, tropical rainforests grow here.

The subtropical belt occupies large spaces between the 25th and 40th parallels of northern and southern latitudes. This belt is characterized by a change in air masses according to the seasons of the year: in summer the entire region is occupied by tropical air, in winter - by air from temperate latitudes. Three climatic regions are distinguished here: western, central and eastern. The western climatic region covers the western parts of the continents: the Mediterranean coast, California, the central part of the Andes, southwest Australia. In summer, tropical air moves here, which creates an area of ​​high pressure. The result is dry and sunny weather. Winter is warm and humid. This climate is sometimes called Mediterranean.

A completely different climatic regime is observed in East Asia and in the southeastern part of North America. In summer, moist masses of tropical air from the ocean (summer monsoons) come here, bringing great cloudiness and precipitation. And the winter monsoons bring streams of dry continental air from temperate latitudes. The temperature of the coldest month is above 0 °C.

In the central region (Eastern Turkey, Iran, Afghanistan, the Great Basin in North America), dry air prevails all year round: in summer - tropical, in winter - continental air of temperate latitudes. Summer here is hot and dry; winters are short and wet, although the total amount of precipitation does not exceed 400 mm. In winter, there are frosts, snow falls, but a stable snow cover does not form. The daily temperature amplitudes are large (up to 30 °C), and there is a big difference between the warmest and coldest months. Here, in the central regions of the continents, deserts are located.

The temperate zone occupies areas north and south of the subtropics to about the polar circles. The southern hemisphere is dominated by an oceanic climate, while the northern hemisphere has three climatic regions: western, central and eastern.

In the west of Europe and Canada, in the south of the Andes, moist sea air of temperate latitudes prevails, brought by westerly winds from the oceans (500-1000 mm of precipitation per year). Precipitation is evenly distributed throughout the year, and there are no dry periods. Under the influence of the oceans, the course of temperatures is smooth, the annual amplitudes are small. Cold snaps bring Arctic (Antarctic) air masses, upon receipt of which the temperature drops in winter. At this time there are heavy snowfalls. Summer is long, cool, there are no sharp changes in air temperature.

In the east (northeast of China, the Far East), the climate is monsoonal. In winter, cold continental air masses form over the mainland. The temperature of the coldest month ranges from -5 to -25 °C. In summer, the wet monsoons bring a large amount of precipitation to the mainland.

In the center (middle zone of Russia, Ukraine, north of Kazakhstan, south of Canada), continental air of temperate latitudes is formed. Often in winter, arctic air comes here with very low temperatures. Winter is long, frosty; snow cover lasts for more than three months. Summer is rainy and warm. The amount of precipitation decreases as you move deeper into the continent (from 700 to 200 mm). The most characteristic feature of the climate of this region is the sharp temperature fluctuations throughout the year, the uneven distribution of precipitation, which sometimes causes droughts.

Subarctic and subantarctic belts.

These transitional zones are located north of the temperate zone (in the Northern Hemisphere) and south of it (in the Southern Hemisphere) - subarctic and subantarctic. They are characterized by a change in air masses by season: in summer - the air of temperate latitudes, in winter - arctic (antarctic). Summer here is short, cool, with an average temperature of the warmest month from 0 to 12 ° C, with little precipitation (average 200 mm), with frequent returns of cold weather. Winter is long, frosty, with blizzards and deep snows. In the Northern Hemisphere, at these latitudes, the tundra zone is located.

Arctic and Antarctic belts.

In the polar belts, cold air masses form under conditions of high pressure. These belts are characterized by long polar nights and polar days. Their duration at the poles reaches six months. Although the sun does not set below the horizon in summer, it does not rise high, its rays glide over the surface and give little heat. During the short summer, snow and ice do not have time to melt, so the ice cover remains in these areas. It covers Greenland and Antarctica with a thick layer, and ice mountains - icebergs - float in the polar regions of the oceans. Cold air accumulating over the polar regions is carried by strong winds to the temperate zone. On the outskirts of Antarctica, winds reach speeds of 100 m/s. The Arctic and Antarctica are the "refrigerators" of the Earth.

In the territory of even a small area, climatic conditions are not uniform. Under the influence of local factors: small landforms, exposure of slopes, soil and ground features, the nature of the vegetation cover, special conditions are created, called the microclimate.

The study of the microclimate is important for the development of many branches of agriculture, especially field crops, horticulture, and vegetable growing.



The content of the article

CLIMATE, long-term weather patterns in the area. The weather at any given time is characterized by certain combinations of temperature, humidity, wind direction and speed. In some types of climate, the weather changes significantly every day or seasonally, in others it remains the same. Climate descriptions are based on statistical analysis of average and extreme meteorological characteristics. As a factor in the natural environment, climate influences the geographic distribution of vegetation, soils and water resources and, consequently, land use and the economy. Climate also has an impact on living conditions and human health.

Climatology is the science of climate that studies the causes of the formation of different types of climate, their geographical location and the relationship between climate and other natural phenomena. Climatology is closely related to meteorology - a branch of physics that studies the short-term states of the atmosphere, i.e. weather.

CLIMATE FORMING FACTORS

The position of the earth.

When the Earth revolves around the Sun, the angle between the polar axis and the perpendicular to the plane of the orbit remains constant and amounts to 23° 30°. This movement explains the change in the angle of incidence of the sun's rays on the earth's surface at noon at a certain latitude during the year. The greater the angle of incidence of the sun's rays on the Earth in a given place, the more efficiently the Sun heats the surface. Only between the Northern and Southern tropics (from 23° 30º N to 23° 30º S) does the sun's rays fall vertically on the Earth at certain times of the year, and here the Sun always rises high above the horizon at noon. Therefore, in the tropics it is usually warm at any time of the year. At higher latitudes, where the Sun is lower above the horizon, the heating of the earth's surface is less. There are significant seasonal changes in temperature (which does not happen in the tropics), and in winter the angle of incidence of the sun's rays is relatively small and the days are much shorter. At the equator, day and night are always of equal length, while at the poles the day lasts the entire summer half of the year, and in winter the sun never rises above the horizon. The length of the polar day only partly compensates for the low position of the Sun above the horizon, and as a result, the summer here is cool. In dark winters, the polar regions quickly lose heat and become very cold.

Distribution of land and sea.

Water heats up and cools down more slowly than land. Therefore, the air temperature over the oceans has less daily and seasonal changes than over the continents. In coastal areas, where winds blow from the sea, summers are generally cooler and winters warmer than in the interior of the continents at the same latitude. The climate of such windward coasts is called maritime. The interior regions of the continents in temperate latitudes are characterized by significant differences in summer and winter temperatures. In such cases, one speaks of a continental climate.

Water areas are the main source of atmospheric moisture. When winds blow from warm oceans to land, there is a lot of precipitation. Windward coasts tend to have higher relative humidity and cloudiness and more foggy days than inland regions.

Atmospheric circulation.

The nature of the baric field and the rotation of the Earth determine the general circulation of the atmosphere, due to which heat and moisture are constantly redistributed over the earth's surface. Winds blow from areas of high pressure to areas of low pressure. High pressure is usually associated with cold, dense air, while low pressure is associated with warm, less dense air. The rotation of the Earth causes air currents to deviate to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This deviation is called the Coriolis effect.

In both the Northern and Southern Hemispheres, there are three main wind zones in the surface layers of the atmosphere. In the intratropical convergence zone near the equator, the northeast trade wind converges with the southeast. Trade winds originate in subtropical areas of high pressure, most developed over the oceans. Air currents, moving towards the poles and deviating under the influence of the Coriolis force, form the predominant western transport. In the region of polar fronts of temperate latitudes, western transport meets cold air of high latitudes, forming a zone of baric systems with low pressure in the center (cyclones) moving from west to east. Although the air currents in the polar regions are not so pronounced, polar eastward transport is sometimes distinguished. These winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere. Masses of cold air often penetrate temperate latitudes.

Winds in the areas of convergence of air currents form ascending air currents, which cool with height. Cloud formation is possible, often accompanied by precipitation. Therefore, in the intratropical convergence zone and frontal zones in the belt of predominant western transport, a lot of precipitation falls.

Winds blowing in higher layers of the atmosphere close the circulation system in both hemispheres. Air rising up in convergence zones rushes into areas of high pressure and sinks there. At the same time, with increasing pressure, it heats up, which leads to the formation of a dry climate, especially on land. Such downward air currents determine the climate of the Sahara, located in the subtropical high pressure belt in North Africa.

Seasonal changes in heating and cooling cause seasonal movements of the main baric formations and wind systems. Wind zones in summer shift towards the poles, which leads to changes in weather conditions at a given latitude. Thus, the African savannahs, covered with grassy vegetation with sparsely growing trees, are characterized by rainy summers (due to the influence of the intratropical convergence zone) and dry winters, when a high pressure area with descending air currents shifts to this territory.

Seasonal changes in the general circulation of the atmosphere are also affected by the distribution of land and sea. In summer, when the Asian continent warms up and a lower pressure area is established above it than over the surrounding oceans, the coastal southern and southeastern regions are affected by moist air currents directed from the sea to land and bringing heavy rains. In winter, air flows from the cold surface of the mainland to the oceans, and much less rain falls. These winds, which change direction with the seasons, are called monsoons.

ocean currents

are formed under the influence of surface winds and differences in water density due to changes in its salinity and temperature. The direction of the currents is influenced by the Coriolis force, the shape of the sea basins and the outlines of the coasts. In general, the circulation of ocean currents is similar to the distribution of air currents over the oceans and occurs clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

Crossing the warm currents heading towards the poles, the air becomes warmer and more humid and has a corresponding effect on the climate. Ocean currents heading towards the equator carry cool waters. Passing along the western outskirts of the continents, they lower the temperature and moisture content of the air, and, accordingly, the climate under their influence becomes cooler and drier. Due to the condensation of moisture near the cold surface of the sea, fog often occurs in such areas.

The relief of the earth's surface.

Large landforms have a significant impact on the climate, which varies depending on the height of the terrain and the interaction of air currents with orographic obstacles. The air temperature usually decreases with height, which leads to the formation of a cooler climate in the mountains and on the plateau than in the adjacent lowlands. In addition, hills and mountains form obstacles that force the air to rise and expand. As it expands, it cools. This cooling, called adiabatic, often results in moisture condensation and the formation of clouds and precipitation. Most of the precipitation caused by the barrier effect of mountains falls on their windward side, while the leeward side remains in the "rain shadow". Air descending on leeward slopes heats up as it compresses, creating a warm, dry wind known as a foehn.

CLIMATE AND LATITUDE

In climatic surveys of the Earth, it is expedient to consider latitudinal zones. The distribution of climatic zones in the Northern and Southern hemispheres is symmetrical. Tropical, subtropical, temperate, subpolar and polar zones are located north and south of the equator. Baric fields and zones of prevailing winds are also symmetrical. Consequently, most climate types in one hemisphere can be found at similar latitudes in the other hemisphere.

MAIN CLIMATE TYPES

The classification of climates provides an ordered system for characterizing climate types, their zoning and mapping. Climate types that prevail over vast areas are called macroclimates. A macroclimatic region should have more or less uniform climatic conditions that distinguish it from other regions, although they are only a generalized characteristic (since there are no two places with an identical climate), more in line with realities than the allocation of climatic regions only on the basis of belonging to a certain latitude. - geographic zone.

Ice sheet climate

dominates Greenland and Antarctica, where average monthly temperatures are below 0 ° C. During the dark winter season, these regions do not receive solar radiation at all, although there are twilight and auroras. Even in summer, the sun's rays fall on the earth's surface at a slight angle, which reduces the heating efficiency. Most of the incoming solar radiation is reflected by the ice. In both summer and winter, low temperatures prevail in the elevated regions of the Antarctic ice sheet. The climate of the interior of Antarctica is much colder than the climate of the Arctic, since the southern mainland is large and high, and the Arctic Ocean moderates the climate, despite the wide distribution of pack ice. In summer, during short periods of warming, drift ice sometimes melts.

Precipitation on ice sheets falls in the form of snow or small particles of ice mist. Inland areas receive only 50-125 mm of precipitation annually, but more than 500 mm can fall on the coast. Sometimes cyclones bring clouds and snow to these areas. Snowfalls are often accompanied by strong winds that carry significant masses of snow, blowing it off the rocks. Strong katabatic winds with snowstorms blow from the cold ice sheet, bringing snow to the coast.

subpolar climate

manifests itself in the tundra regions on the northern outskirts of North America and Eurasia, as well as on the Antarctic Peninsula and adjacent islands. In eastern Canada and Siberia, the southern boundary of this climatic zone runs well south of the Arctic Circle due to the strongly pronounced influence of vast land masses. This leads to long and extremely cold winters. Summers are short and cool, with average monthly temperatures rarely exceeding +10°C. To some extent, long days compensate for the short duration of summer, but in most of the territory the heat received is not enough to completely thaw the soil. Permanently frozen ground, called permafrost, inhibits plant growth and the infiltration of meltwater into the ground. Therefore, in summer, flat areas turn out to be swampy. On the coast, winter temperatures are somewhat higher, and summer temperatures are somewhat lower than in the interior of the mainland. In summer, when humid air is over cold water or sea ice, fog often occurs on Arctic coasts.

The annual amount of precipitation usually does not exceed 380 mm. Most of them fall in the form of rain or snow in summer, when cyclones pass. On the coast, the bulk of precipitation can be brought by winter cyclones. But the low temperatures and clear weather of the cold season, characteristic of most areas with a subpolar climate, are unfavorable for significant snow accumulation.

subarctic climate

also known as the "climate of the taiga" (according to the predominant type of vegetation - coniferous forests). This climatic zone covers the temperate latitudes of the Northern Hemisphere - the northern regions of North America and Eurasia, located immediately south of the subpolar climatic zone. There are sharp seasonal climatic differences due to the position of this climatic zone at fairly high latitudes in the interior of the continents. Winters are long and extremely cold, and the further north you go, the shorter the days. Summers are short and cool with long days. In winter, the period with negative temperatures is very long, and in summer the temperature can sometimes exceed +32° С. the annual temperature range reaches 62 ° C. A milder climate is typical for coastal areas, such as southern Alaska or northern Scandinavia.

In most of the considered climatic zone, less than 500 mm of precipitation per year falls, and their amount is maximum on the windward coasts and minimum in the interior of Siberia. Very little snow falls in winter, snowfalls are associated with rare cyclones. Summers are usually wetter, and it rains mainly during the passage of atmospheric fronts. The coasts are often foggy and overcast. In winter, in severe frosts, icy fogs hang over the snow cover.

Humid continental climate with short summers

characteristic of a vast band of temperate latitudes of the Northern Hemisphere. In North America, it extends from the prairies in south-central Canada to the coast of the Atlantic Ocean, and in Eurasia it covers most of Eastern Europe and parts of Central Siberia. The same type of climate is observed in the Japanese island of Hokkaido and in the south of the Far East. The main climatic features of these regions are determined by the prevailing westerly transport and the frequent passage of atmospheric fronts. In severe winters, average air temperatures can drop to -18 ° C. Summers are short and cool, with a frost-free period of less than 150 days. The annual temperature range is not as large as in the subarctic climate. In Moscow, the average January temperatures are -9° C, July - +18° C. In this climatic zone, spring frosts pose a constant threat to agriculture. In the coastal provinces of Canada, in New England and on about. Hokkaido's winters are warmer than inland areas, as easterly winds occasionally bring in warmer ocean air.

Annual rainfall ranges from less than 500 mm in the interior of the continents to over 1000 mm on the coasts. In most of the region, precipitation occurs mainly in summer, often during thunderstorms. Winter precipitation, mainly in the form of snow, is associated with the passage of fronts in cyclones. Blizzards are often observed in the rear of a cold front.

Humid continental climate with long summers.

Air temperatures and the duration of the summer season increase to the south in areas of humid continental climate. This type of climate is manifested in the temperate latitudinal zone of North America from the eastern part of the Great Plains to the Atlantic coast, and in southeastern Europe - in the lower reaches of the Danube. Similar climatic conditions are also expressed in northeastern China and central Japan. Here, too, western transport predominates. The average temperature of the warmest month is +22°С (but temperatures can exceed +38°С), summer nights are warm. Winters are not as cold as in areas of humid continental climate with short summers, but temperatures sometimes drop below 0°C. in January -4° С, and in July - +24° С. On the coast, annual temperature amplitudes decrease.

Most often, in a humid continental climate with a long summer, from 500 to 1100 mm of precipitation falls annually. The greatest amount of precipitation is brought by summer thunderstorms during the growing season. In winter, rains and snowfalls are mainly associated with the passage of cyclones and related fronts.

Maritime climate of temperate latitudes

inherent in the western coasts of the continents, primarily in northwestern Europe, the central part of the Pacific coast of North America, southern Chile, southeastern Australia and New Zealand. The prevailing westerly winds blowing from the oceans have a softening effect on the course of air temperature. Winters are mild with average temperatures of the coldest month above 0°C, but when the Arctic air currents reach the coasts, there are also frosts. Summers are generally quite warm; during intrusions of continental air during the daytime, the temperature can rise to + 38 ° C for a short time. This type of climate with a small annual temperature amplitude is the most moderate among the climates of temperate latitudes. For example, in Paris, the average temperature in January is + 3 ° C, in July - + 18 ° C.

In areas of temperate maritime climate, the average annual precipitation ranges from 500 to 2500 mm. The windward slopes of the coastal mountains are the most humid. Precipitation is fairly even throughout the year in many areas, with the exception being the Pacific Northwest of the United States, which has very wet winters. Cyclones moving from the oceans bring a lot of precipitation to the western continental margins. In winter, as a rule, cloudy weather persists with light rains and occasional short-term snowfalls. Fogs are common on the coasts, especially in summer and autumn.

Humid subtropical climate

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

Subtropical climate with dry summers

typical of the western coasts of the continents north and south of the tropics. In Southern Europe and North Africa, such climatic conditions are typical for the coasts of the Mediterranean Sea, which was the reason to call this climate also Mediterranean. The same climate is in southern California, the central regions of Chile, in the extreme south of Africa and in a number of areas in southern Australia. All these regions have hot summers and mild winters. As in the humid subtropics, there are occasional frosts in winter. In inland areas, summer temperatures are much higher than on the coasts, and often the same as in tropical deserts. In general, clear weather prevails. In summer, on the coasts near which ocean currents pass, there are often fogs. For example, in San Francisco, summers are cool, foggy, and the warmest month is September.

The maximum precipitation is associated with the passage of cyclones in winter, when the prevailing westerly air currents shift towards the equator. The influence of anticyclones and downward air currents under the oceans determine the dryness of the summer season. The average annual precipitation in a subtropical climate varies from 380 to 900 mm and reaches maximum values ​​on the coasts and mountain slopes. In the summer, there is usually not enough rainfall for the normal growth of trees, and therefore a specific type of evergreen shrub vegetation develops there, known as maquis, chaparral, mali, machia and fynbosh.

Semi-arid climate of temperate latitudes

(synonym - steppe climate) is characteristic mainly for inland regions, remote from the oceans - sources of moisture - and usually located in the rain shadow of high mountains. The main regions with a semi-arid climate are the intermountain basins and the Great Plains of North America and the steppes of central Eurasia. Hot summers and cold winters are due to the inland position in temperate latitudes. At least one winter month has an average temperature below 0 ° C, and the average temperature of the warmest summer month exceeds + 21 ° C. The temperature regime and the duration of the frost-free period vary significantly depending on latitude.

The term "semiarid" is used to characterize this climate because it is less dry than the actual arid climate. The average annual precipitation is usually less than 500 mm but more than 250 mm. Since the development of steppe vegetation at higher temperatures requires more precipitation, the latitudinal-geographical and altitudinal position of the area is determined by climatic changes. For a semi-arid climate, there are no general regularities in the distribution of precipitation throughout the year. For example, areas bordering the subtropics with dry summers experience a maximum of precipitation in winter, while areas adjacent to areas of a humid continental climate experience rainfall mainly in summer. Mid-latitude cyclones bring most of the winter precipitation, which often falls as snow and can be accompanied by strong winds. Summer thunderstorms often come with hail. The amount of precipitation varies greatly from year to year.

Arid climate of temperate latitudes

is inherent mainly in the Central Asian deserts, and in the western United States - only in small areas in intermountain basins. Temperatures are the same as in regions with a semi-arid climate, but the precipitation here is not enough for the existence of a closed natural vegetation cover and the average annual amounts usually do not exceed 250 mm. As in semi-arid climatic conditions, the amount of precipitation that determines aridity depends on the thermal regime.

Semi-arid climate of low latitudes

mostly typical of the margins of tropical deserts (eg the Sahara and the deserts of central Australia), where downdrafts in subtropical high pressure zones preclude precipitation. The climate under consideration differs from the semi-arid climate of temperate latitudes by very hot summers and warm winters. Average monthly temperatures are above 0°C, although frosts sometimes occur in winter, especially in areas furthest from the equator and located at high altitudes. The amount of precipitation required for the existence of dense natural herbaceous vegetation is higher here than in temperate latitudes. In the equatorial zone, it rains mainly in summer, while on the outer (northern and southern) margins of the deserts, the maximum precipitation occurs in winter. Precipitation mostly falls in the form of thunderstorms, and in winter rains are brought by cyclones.

Arid climate of low latitudes.

This is a hot dry climate of tropical deserts, stretching along the Northern and Southern tropics and being influenced by subtropical anticyclones for most of the year. Salvation from the sweltering summer heat can only be found on the coasts washed by cold ocean currents, or in the mountains. On the plains, the average summer temperatures noticeably exceed + 32 ° C, winter ones are usually above + 10 ° C.

In most of this climatic region, the average annual precipitation does not exceed 125 mm. It happens that at many meteorological stations for several years in a row precipitation is not recorded at all. Sometimes the average annual precipitation can reach 380 mm, but this is still enough only for the development of sparse desert vegetation. Occasionally, precipitation occurs in the form of short-lived heavy thunderstorms, but the water quickly drains to form flash floods. The driest regions are along the western coasts of South America and Africa, where cold ocean currents prevent cloud formation and precipitation. These coasts often have fogs formed by the condensation of moisture in the air over the colder surface of the ocean.

Variable humid tropical climate.

Areas with such a climate are located in tropical sublatitudinal zones, a few degrees north and south of the equator. This climate is also called tropical monsoon, as it prevails in those parts of South Asia that are influenced by monsoons. Other areas with such a climate are the tropics of Central and South America, Africa and Northern Australia. Average summer temperatures are usually approx. + 27 ° С, and winter - approx. + 21 ° C. The hottest month, as a rule, precedes the summer rainy season.

Average annual rainfall ranges from 750 to 2000 mm. During the summer rainy season, the intertropical convergence zone exerts a decisive influence on the climate. There are often thunderstorms here, sometimes continuous cloud cover with prolonged rains persists for a long time. Winter is dry, as subtropical anticyclones dominate this season. In some areas, rain does not fall for two to three winter months. In South Asia, the wet season coincides with the summer monsoon, which brings moisture from the Indian Ocean, and Asian continental dry air masses spread here in winter.

humid tropical climate,

or the climate of tropical rainforests, common in equatorial latitudes in the Amazon basin in South America and the Congo in Africa, on the Malay Peninsula and on the islands of Southeast Asia. In the humid tropics, the average temperature of any month is not less than + 17 ° C, usually the average monthly temperature is approx. + 26 ° C. As in the variable humid tropics, due to the high midday position of the Sun above the horizon and the same length of the day throughout the year, seasonal temperature fluctuations are small. Moist air, cloudiness and dense vegetation prevent night cooling and maintain maximum daytime temperatures below +37°C, lower than at higher latitudes.

The average annual rainfall in the humid tropics ranges from 1500 to 2500 mm, the distribution over the seasons is usually fairly even. Precipitation is mainly associated with the intratropical convergence zone, which is located slightly north of the equator. Seasonal shifts of this zone to the north and south in some areas lead to the formation of two precipitation maxima during the year, separated by drier periods. Every day, thousands of thunderstorms roll over the humid tropics. In the intervals between them, the sun shines in full force.

Highland climates.

In highland areas, a significant variety of climatic conditions is due to the latitudinal-geographical position, orographic barriers, and different exposure of the slopes in relation to the Sun and moisture-carrying air currents. Even at the equator in the mountains there are snowfields-migrations. The lower boundary of the eternal snows descends towards the poles, reaching sea level in the polar regions. Like it, other boundaries of high-altitude thermal belts decrease as they approach high latitudes. Windward slopes of mountain ranges receive more precipitation. On mountain slopes open to the intrusions of cold air, a drop in temperature is possible. In general, the climate of the highlands is characterized by lower temperatures, higher cloudiness, more precipitation, and a more complex wind regime than the climate of the plains at the corresponding latitudes. The nature of seasonal changes in temperature and precipitation in the highlands is usually the same as in the adjacent plains.

MESO AND MICROCLIMATES

Territories that are inferior in size to macroclimatic regions also have climatic features that deserve special study and classification. Mesoclimates (from the Greek meso - medium) are the climates of territories several square kilometers in size, for example, wide river valleys, intermountain depressions, basins of large lakes or cities. In terms of distribution area and nature of differences, mesoclimates are intermediate between macroclimates and microclimates. The latter characterize the climatic conditions in small areas of the earth's surface. Microclimatic observations are carried out, for example, on the streets of cities or on test sites established within a homogeneous plant community.

EXTREME CLIMATE INDICATORS

Climatic characteristics such as temperature and precipitation vary widely between extreme (minimum and maximum) values. Although they are rare, extremes are as important as averages in understanding the nature of climate. The climate of the tropics is the warmest, with the climate of tropical rainforests being hot and humid, and the arid climate of low latitudes being hot and dry. The maximum air temperatures are noted in tropical deserts. The highest temperature in the world - +57.8 ° C - was recorded in El Aziziya (Libya) on September 13, 1922, and the lowest - -89.2 ° C at the Soviet Vostok station in Antarctica on July 21, 1983.

Rainfall extremes have been recorded in different parts of the world. For example, for 12 months from August 1860 to July 1861, 26,461 mm fell in the town of Cherrapunji (India). The average annual rainfall in this point, one of the rainiest on the planet, is approx. 12,000 mm. Less data are available on the amount of snowfall. At Paradise Ranger Station in Mount Rainier National Park (Washington, USA), 28,500 mm of snow was recorded during the winter of 1971-1972. At many meteorological stations in the tropics with long series of observations, precipitation has never been recorded at all. There are many such places in the Sahara and on the west coast of South America.

At extreme wind speeds, measuring instruments (anemometers, anemographs, etc.) often failed. The highest wind speeds in the surface air probably develop in tornadoes, where it is estimated that they can be much higher than 800 km/h. In hurricanes or typhoons, winds sometimes reach speeds of over 320 km/h. Hurricanes are very common in the Caribbean and Western Pacific.

IMPACT OF CLIMATE ON BIOTA

The temperature and light regimes and moisture supply necessary for the development of plants and limiting their geographical distribution depend on the climate. Most plants cannot grow at temperatures below +5°C, and many species die at sub-zero temperatures. As temperatures increase, the moisture requirements of plants increase. Light is essential for photosynthesis, as well as for flowering and seed development. Shading the soil with canopy trees in a dense forest inhibits the growth of lower plants. An important factor is also the wind, which significantly changes the regime of temperature and humidity.

The vegetation of each region is an indicator of its climate, since the distribution of plant communities is largely driven by climate. The vegetation of the tundra in a subpolar climate is formed only by such undersized forms as lichens, mosses, grasses and low shrubs. The short growing season and widespread permafrost make it difficult for trees to grow everywhere except in river valleys and south-facing slopes, where the soil thaws to a greater depth in summer. Coniferous forests of spruce, fir, pine and larch, also called taiga, grow in a subarctic climate.

Humid regions of temperate and low latitudes are especially favorable for forest growth. The densest forests are confined to areas of temperate maritime climate and humid tropics. Areas of humid continental and humid subtropical climate are also mostly forested. In the presence of a dry season, such as in subtropical climates with dry summers or variable humid tropical climates, the plants adapt accordingly, forming either a stunted or sparse tree layer. Thus, in the savannas, under conditions of a variable humid tropical climate, grasslands with single trees growing at great distances from one another predominate.

In semi-arid climates of temperate and low latitudes, where everywhere (except for river valleys) it is too dry for tree growth, herbaceous steppe vegetation dominates. The grasses here are stunted, and an admixture of semi-shrubs and semi-shrubs is also possible, for example, wormwood in North America. In temperate latitudes, grass steppes in more humid conditions at the borders of their range are replaced by tall grass prairies. In arid conditions, plants grow far apart, often have thick bark or fleshy stems and leaves that can store moisture. The driest regions of tropical deserts are completely devoid of vegetation and are exposed rocky or sandy surfaces.

The climatic altitudinal zonality in the mountains determines the corresponding vertical differentiation of vegetation - from grassy communities of foothill plains to forests and alpine meadows.

Many animals are able to adapt to a wide range of climatic conditions. For example, mammals in cold climates or in winter have warmer fur. However, the availability of food and water is also important for them, which varies depending on the climate and season. Many species of animals are characterized by seasonal migrations from one climatic region to another. For example, in winter, when grasses and shrubs dry up in the variable humid tropical climate of Africa, mass migrations of herbivores and predators to more humid areas occur.

In the natural zones of the globe, soils, vegetation and climate are closely interrelated. Heat and moisture determine the nature and pace of chemical, physical and biological processes, as a result of which rocks on slopes of different steepness and exposure change and a huge variety of soils is created. Where the soil is bound by permafrost for most of the year, as in the tundra or high in the mountains, soil formation processes are slowed down. In arid conditions, soluble salts are usually found on the soil surface or in near-surface horizons. In humid climates, excess moisture seeps down, carrying soluble mineral compounds and clay particles to considerable depths. Some of the most fertile soils are products of recent accumulation - wind, fluvial or volcanic. Such young soils have not yet undergone strong leaching and therefore retained nutrient reserves.

The distribution of crops and soil cultivation practices are closely related to climatic conditions. Bananas and rubber trees require an abundance of warmth and moisture. Date palms grow well only in oases in arid low-latitude areas. For most crops in arid conditions of temperate and low latitudes, irrigation is necessary. The usual type of land use in areas of semi-arid climate, where grasslands are common, is grazing. Cotton and rice have a longer growing season than spring wheat or potatoes, and all of these crops suffer from frost. In the mountains, agricultural production is differentiated by altitudinal zones in the same way as natural vegetation. Deep valleys in the humid tropics of Latin America are located in the hot zone (tierra caliente) and tropical crops are grown there. At somewhat higher elevations in the temperate zone (tierra templada), coffee is the typical crop. Above is the cold zone (tierra fria), where cereals and potatoes are grown. In an even colder belt (tierra helada), located just below the snow line, alpine meadows are grazing, and crops are extremely limited.

The climate affects the health and living conditions of people as well as their economic activities. The human body loses heat through radiation, conduction, convection and evaporation of moisture from the surface of the body. If these losses are too great in cold weather or too small in hot weather, the person experiences discomfort and may become ill. Low relative humidity and high wind speed increase the cooling effect. Weather changes lead to stress, impair appetite, disrupt biorhythms and reduce the resistance of the human body to disease. Climate also influences the conditions in which disease-causing pathogens live, and therefore seasonal and regional disease outbreaks occur. Epidemics of pneumonia and influenza in temperate latitudes often occur in winter. Malaria is common in the tropics and subtropics, where there are conditions for the reproduction of malarial mosquitoes. Diet-related diseases are indirectly climate-related, as food produced in a given region may be deficient in certain nutrients as a result of climate influences on plant growth and soil composition.

CLIMATE CHANGE

Rocks, plant fossils, landforms, and glacial deposits contain information about significant fluctuations in average temperatures and precipitation over geological time. Climate change can also be studied by analyzing tree rings, alluvial deposits, ocean and lake bottom sediments, and organic peatland deposits. Over the past few million years there has been a general cooling of the climate, and now, judging by the continuous reduction of the polar ice sheets, we seem to be at the end of the ice age.

Climate change over a historical period can sometimes be reconstructed from information about famines, floods, abandoned settlements, and migrations of peoples. Continuous series of air temperature measurements are available only for meteorological stations located mainly in the Northern Hemisphere. They cover only a little over one century. These data indicate that over the past 100 years, the average temperature on the globe has increased by almost 0.5 ° C. This change did not occur smoothly, but abruptly - sharp warmings were replaced by relatively stable stages.

Experts from various fields of knowledge have proposed numerous hypotheses to explain the causes of climate change. Some believe that climatic cycles are determined by periodic fluctuations in solar activity with an interval of approx. 11 years. Annual and seasonal temperatures could be influenced by changes in the shape of the Earth's orbit, which led to a change in the distance between the Sun and the Earth. The Earth is currently closest to the Sun in January, but approximately 10,500 years ago it was in this position in July. According to another hypothesis, depending on the angle of inclination of the earth's axis, the amount of solar radiation entering the Earth changed, which affected the general circulation of the atmosphere. It is also possible that the polar axis of the Earth occupied a different position. If the geographic poles were at the latitude of the modern equator, then, accordingly, the climatic zones also shifted.

The so-called geographic theories explain long-term climate fluctuations by movements of the earth's crust and changes in the position of continents and oceans. In the light of global plate tectonics, continents have moved over geological time. As a result, their position in relation to the oceans, as well as in latitude, changed. In the process of mountain building, mountain systems with a cooler and, possibly, more humid climate were formed.

Air pollution also contributes to climate change. Large masses of dust and gases released into the atmosphere during volcanic eruptions occasionally became an obstacle to solar radiation and led to cooling of the earth's surface. An increase in the concentration of certain gases in the atmosphere exacerbates the overall warming trend.

Greenhouse effect.

Like the glass roof of a greenhouse, many gases pass most of the thermal and light energy of the Sun to the Earth's surface, but prevent the rapid return of the heat radiated by it to the surrounding space. The main gases causing the "greenhouse" effect are water vapor and carbon dioxide, as well as methane, fluorocarbons and nitrogen oxides. Without the greenhouse effect, the temperature of the earth's surface would drop so much that the entire planet would be covered with ice. However, an excessive increase in the greenhouse effect can also be catastrophic.

Since the beginning of the industrial revolution, the amount of greenhouse gases (mainly carbon dioxide) in the atmosphere has increased due to human activities and especially the burning of fossil fuels. Many scientists now believe that the rise in global mean temperature since 1850 was mainly due to increases in atmospheric carbon dioxide and other anthropogenic greenhouse gases. If current trends in fossil fuel use continue into the 21st century, global average temperatures could rise by 2.5–8°C by 2075. If fossil fuels are used faster than they are currently, this temperature rise could occur as early as 2030.

The projected increase in temperature could lead to the melting of the polar ice caps and most mountain glaciers, causing sea levels to rise by 30 to 120 cm. All of this could also affect changes in the Earth's weather patterns, with possible consequences such as extended droughts in the world's leading agricultural regions .

However, global warming as a consequence of the greenhouse effect can be slowed down if carbon dioxide emissions from burning fossil fuels are reduced. Such a reduction would require restrictions on its use throughout the world, more efficient energy consumption and an increase in the use of alternative energy sources (for example, water, solar, wind, hydrogen, etc.).

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Khromov S.P., Petrosyants M.A. Meteorology and climatology. M., 1994