What climate is typical for Russia: arctic, subarctic, temperate and subtropical. Earth climates All existing types

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if you remove all the lies from the story, this does not mean that only the truth will remain, as a result, nothing may remain at all Stanislav Yezhylets our recent video 10 filled cities got a million views and, as promised, we will soon make a continuation if you watched our previous video put your thumbs up if not look at the link at the top today we will talk about the climate about which historians, as usual, do not agree on something for us, well, they have such an operation on written sources until the 18th century, it is necessary with great care, since nothing is easier than forging paper much more difficult to forge, for example, buildings here and we will not rely on the evidence of which it is almost impossible to falsify and these facts should not be considered separately, but in aggregate about the climate of the 18th century and earlier, much can be said about those buildings and structures that were built at that time, all the facts that we have accumulated indicate that that most of the palaces and mansions that were built before the nineteenth centuries were built under a different warmer climate, in addition, we found other evidence of a sharp climate change, be sure to watch the video to the end a very large area of ​​windows the partition between the windows is equal or even less than the width of the windows themselves and the windows themselves are very high, a stunning huge building, but as we are assured this is a summer palace it was built supposedly in order to come here exclusively in the summer, the version is funny considering that the summer in St. Petersburg is rather cool and short-lived if you look at the facade of the palace, you can see a very large area of ​​windows that is typical for the southern hot regions, they are for the northern territories if in doubt make such windows in your house and then look at the heating bills and questions will disappear immediately later, at the beginning of the 19th century, an annex was made to the palace where the famous lyceum is located in which Alexander Sergeevich Pushkin studied, the annex differs not only in its architectural style, but also in the fact that it has already been built under but The area of ​​the windows is noticeably smaller in many buildings, the heating system was not originally supposed to be installed and it was built later into the finished building of this there is a lot of evidence here, the researchers artyom vaydenkov clearly shows that initially no stoves in the temples were envisaged, well, the designers were apparently forgetful of the temples themselves designed all over the country almost according to a standard project and the stoves were forgotten, the chimneys were hollowed out in the walls and rather carelessly and then sealed up also clearly in a hurry, apparently it was not up to beauty then the builders of the hollowed out chimneys could see soot and soot, of course, the stoves themselves were taken away long ago, but in the fact that they were here there is no doubt another example looks like a cavalier ska and a silver dining stove just put the wall decoration in the corner the presence of the stove in this corner ignores that is, it was done before it appeared there if you look at the upper part you can see that it is not tight adjacent to the wall posco Only the curly gilded aryl decoration of the top of the wall interferes with it, and even look at the size of the stove and the size of the rooms, the height of the ceilings in the Catherine's palace, you believe that such stoves could somehow heat up such a room, we are so used to listening to the opinion of the authorities that often seeing it is obvious that we do not believe we will oversee our eyes with various experts who called themselves as such, and let's try to abstract from the explanations of various historians of local history guides, that is, everything that is extremely easy to fake is distorted and just try to see someone's fantasies and what is reality, take a closer look at this photo this building of the Kazan Kremlin the building, as usual, is covered with windows on the horizon, there are no trees, but now not about this, pay attention to the building in the lower right corner, apparently this building has not yet been reconstructed for new climatic conditions. apparently just ru if you find similar photos, share in the comments the task of thermal vestibules is to prevent cold air from entering the main room with vestibules the same story that they were made of chimneys later than the buildings themselves, these frames clearly show that they do not fit into the architectural ensemble of buildings the vestibules are made of a different material, apparently it froze too much then there was no time for delights somewhere the vestibules were made as elegantly as possible and fitted to the style of the building, but somewhere they did not bother at all and made a tyap-blooper, these frames show that there is no vestibule in the old photos of the temple and now he is and the average person will never understand that something was once rebuilt here is another similar example, the same in the old photo there is no vestibule, but now he is why all of a sudden these thermal vestibules were needed so badly for beauty, or maybe this was fashion then on the vestibule do not rush to draw conclusions first look at other facts further

Study methods

To draw conclusions about the peculiarities of the climate, long-term series of observations of the weather are required. In temperate latitudes, they use 25-50-year trends, in tropical ones, shorter ones. Climatic characteristics are derived from observations of meteorological elements, the most important of which are atmospheric pressure, wind speed and direction, air temperature and humidity, cloudiness and precipitation. In addition, they study the duration of solar radiation, the duration of the frost-free period, the visibility range, the temperature of the upper layers of soil and water in reservoirs, the evaporation of water from the earth's surface, the height and condition of the snow cover, all kinds of atmospheric phenomena, total solar radiation, radiation balance and much more.

The applied branches of climatology use the climate characteristics necessary for their purposes:

• in agroclimatology - the sum of the temperatures of the growing season;
• in bioclimatology and technical climatology - effective temperatures;

Complex indicators are also used, determined by several main meteorological elements, namely, all kinds of coefficients (continentality, aridity, moisture), factors, indices.

Long-term average values ​​of meteorological elements and their complex indicators (annual, seasonal, monthly, daily, etc.), their sums, recurrence periods are considered climatic norms. Non-coincidence with them in specific periods are considered deviations from these norms.

Models of general atmospheric circulation are used to assess future climate changes [ ] .

Climate-forming factors

The planet's climate depends on a whole complex of astronomical and geographical factors that affect the total amount of solar radiation received by the planet, as well as its distribution over seasons, hemispheres and continents. With the onset of the industrial revolution, human activity becomes a climate-forming factor.

Astronomical factors

Astronomical factors include the luminosity of the Sun, the position and motion of the planet Earth relative to the Sun, the angle of inclination of the Earth's axis of rotation to the plane of its orbit, the speed of rotation of the Earth, and the density of matter in the surrounding space. The rotation of the globe around its axis causes daily changes in the weather, the movement of the Earth around the Sun and the inclination of the axis of rotation to the orbital plane cause seasonal and latitudinal differences in weather conditions. The eccentricity of the Earth's orbit - affects the distribution of heat between the Northern and Southern hemispheres, as well as the magnitude of seasonal changes. The speed of rotation of the Earth practically does not change, it is a constantly acting factor. Due to the rotation of the Earth, trade winds and monsoons exist, as well as cyclones. [ ]

Geographic factors

Geographic factors include

Influence of solar radiation

The most important element of the climate, affecting the rest of its characteristics, primarily the temperature, is the radiant energy of the Sun. The huge energy released in the process of nuclear fusion on the Sun is radiated into outer space. The power of solar radiation received by a planet depends on its size and distance from the Sun. The total flux of solar radiation passing per unit of time through a unit area oriented perpendicular to the flux, at a distance of one astronomical unit from the Sun outside the earth's atmosphere, is called the solar constant. In the upper part of the earth's atmosphere, each square meter perpendicular to the sun's rays receives 1,365 W ± 3.4% of solar energy. Energy varies throughout the year due to the ellipticity of the Earth's orbit, with the greatest power absorbed by the Earth in January. Despite the fact that about 31% of the received radiation is reflected back into space, the remainder is enough to support atmospheric and oceanic currents, and to provide energy for almost all biological processes on Earth.

The energy received by the earth's surface depends on the angle of incidence of the sun's rays, it is greatest if this angle is right, but most of the earth's surface is not perpendicular to the sun's rays. The inclination of the rays depends on the latitude of the area, time of year and day, it is greatest at noon on June 22 north of the Tropic of Cancer and on December 22 south of the Tropic of Capricorn, in the tropics the maximum (90 °) is reached 2 times a year.

Another important factor determining the latitudinal climatic regime is the length of daylight hours. Beyond the polar circles, that is, north of 66.5 ° N. NS. and south of 66.5 ° S. NS. the length of daylight hours varies from zero (in winter) to 24 hours in summer, at the equator all year round 12-hour day. Since seasonal changes in inclination angle and day length are more noticeable at higher latitudes, the amplitude of temperature fluctuations throughout the year decreases from the poles to low latitudes.

The receipt and distribution of solar radiation over the surface of the globe without taking into account the climate-forming factors of a particular area is called the solar climate.

The share of solar energy absorbed by the earth's surface varies markedly depending on cloud cover, surface type and terrain elevation, averaging 46% of that supplied to the upper atmosphere. Constant cloudiness, such as at the equator, helps to reflect most of the incoming energy. A water surface absorbs sunlight (except for very inclined ones) better than other surfaces, reflecting only 4-10%. The share of absorbed energy is higher than average in deserts located high above sea level, due to the thinner atmosphere that scatters the sun's rays.

Circulation of the atmosphere

In the most heated places, the heated air has a lower density and rises upward, thus forming a zone of low atmospheric pressure. Similarly, a zone of increased pressure is formed in colder places. Air movement occurs from a zone of high atmospheric pressure to a zone of low atmospheric pressure. Since the closer to the equator and further from the poles the terrain is located, the better it warms up, in the lower layers of the atmosphere there is a predominant movement of air from the poles to the equator.

However, the Earth also rotates on its axis, so the Coriolis force acts on the moving air and deflects this movement to the west. In the upper layers of the troposphere, the reverse movement of air masses is formed: from the equator to the poles. Its Coriolis force constantly bends to the east, and the farther, the more. And in areas about 30 degrees north and south latitude, movement becomes directed from west to east parallel to the equator. As a result, the air trapped in these latitudes has nowhere to go at such an altitude, and it sinks down to the ground. The area of ​​the highest pressure is formed here. Thus, trade winds are formed - constant winds blowing towards the equator and to the west, and since the turning force acts constantly, when approaching the equator, the trade winds blow almost parallel to it. The air currents of the upper layers, directed from the equator to the tropics, are called anti-trade winds. The trade winds and anti-trade winds seem to form an air wheel, along which a continuous circulation of air is maintained between the equator and the tropics. There is an intertropical convergence zone between the trade winds of the Northern and Southern hemispheres.

During the year, this zone shifts from the equator to the warmer summer hemisphere. As a result, in some places, especially in the Indian Ocean basin, where the main direction of air transport in winter is from west to east, in summer it is replaced by the opposite one. These air transfers are called tropical monsoons. Cyclonic activity connects the zone of tropical circulation with circulation in temperate latitudes, and between them there is an exchange of warm and cold air. As a result of inter-latitudinal air exchange, heat is transferred from low latitudes to high latitudes and cold from high latitudes to low latitudes, which leads to the maintenance of thermal equilibrium on Earth.

In fact, the circulation of the atmosphere is constantly changing, both due to seasonal changes in the distribution of heat on the earth's surface and in the atmosphere, and due to the formation and movement of cyclones and anticyclones in the atmosphere. Cyclones and anticyclones generally move towards the east, with cyclones deviating towards the poles, and anticyclones away from the poles.

Climate types

The classification of the Earth's climates can be made either directly by climatic characteristics (classification by V. Köppen), or based on the features of the general circulation of the atmosphere (classification by BP Alisov), or by the nature of geographic landscapes (classification by L. S. Berg). The climatic conditions of the area are primarily determined by the so-called. solar climate - the influx of solar radiation to the upper boundary of the atmosphere, depending on latitude and different at different times and seasons. Nevertheless, the boundaries of climatic zones not only do not coincide with the parallels, but do not even always go around the globe, while there are zones isolated from each other with the same type of climate. The proximity of the sea, the atmospheric circulation system and the height above sea level also have an important influence.

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. The classification has been improved several times, and in the edition of G.T. Trevart (English) Russian there are six classes with sixteen types of climate. Many types of climates according to the Köppen climate classification are known by names associated with the characteristic vegetation of this type. Each type has precise parameters of temperature values, the amount of winter and summer precipitation, this makes it easier to assign a certain place to a certain type of climate, so the Köppen classification has become widespread.

On both sides of the low-pressure belt along the equator, there are zones with increased atmospheric pressure. The oceans are dominated here trade wind with constant east winds, the so-called. trade winds. The weather here is relatively dry (about 500 mm of precipitation per year), with moderate cloud cover, in summer the average temperature is 20-27 ° С, in winter - 10-15 ° С. Precipitation increases sharply on the windward slopes of mountainous islands. Tropical cyclones are relatively rare.

These oceanic areas correspond to tropical desert zones on land with dry tropical climate... The average temperature of the warmest month in the Northern Hemisphere is about 40 ° C, in Australia up to 34 ° C. In northern Africa and in the interior of California, the highest temperatures on Earth are observed - 57-58 ° С, in Australia - up to 55 ° С. In winter, temperatures drop to 10-15 ° C. Temperature changes during the day are very large, can exceed 40 ° C. There is little precipitation - less than 250 mm, often no more than 100 mm per year.

In many tropical regions - Equatorial Africa, South and Southeast Asia, northern Australia - the dominance of the trade winds is replaced subequatorial, or tropical monsoon climate... Here, in the summer, the intertropical convergence zone moves further north of the equator. As a result, the eastern trade wind transport of air masses is replaced by the western monsoon, which is associated with the bulk of the precipitation falling here. The predominant vegetation types are monsoon forests, forest savannas and tall grass savannas

In the subtropics

In the belts of 25-40 ° north latitude and south latitude, subtropical types of climate prevail, which are formed under the conditions of alternating prevailing air masses - tropical in summer, moderate in winter. The average monthly air temperature in summer exceeds 20 ° С, in winter - 4 ° С. On land, the amount and regime of atmospheric precipitation strongly depend on the distance from the oceans; as a result, landscapes and natural zones vary greatly. On each of the continents, three main climatic zones are clearly expressed.

In the west of the continents dominates Mediterranean climate(semi-dry subtropics) with summer anticyclones and winter cyclones. Summer here is hot (20-25 ° С), little cloudy and dry, it rains in winter, relatively cold (5-10 ° С). Average annual precipitation is about 400-600 mm. In addition to the Mediterranean itself, such a climate prevails on the southern coast of Crimea, western California, southern Africa, and southwestern Australia. The predominant type of vegetation is Mediterranean forests and shrubs.

In the east of the continents dominates monsoon subtropical climate... The temperature conditions of the western and eastern outskirts of the continents differ little. Abundant precipitation, brought by the oceanic monsoon, falls here mainly in summer.

Temperate zone

In the zone of year-round prevalence of moderate air masses, intense cyclonic activity causes frequent and significant changes in air pressure and temperature. The prevalence of westerly winds is most noticeable over the oceans and in the Southern Hemisphere. In addition to the main seasons - winter and summer, there are noticeable and rather long transitional ones - autumn and spring. Due to the large differences in temperature and humidity, many researchers classify the climate of the northern part of the temperate zone as subarctic (Köppen's classification), or distinguish it into an independent climatic zone - boreal.

Subpolar

Intense cyclonic activity occurs over the subpolar oceans, the weather is windy and cloudy, and there is a lot of precipitation. Subarctic climate dominates in the north of Eurasia and North America, characterized by dry (precipitation no more than 300 mm per year), long and cold winters, and cold summers. Despite the small amount of precipitation, low temperatures and permafrost contribute to waterlogging of the area. A similar climate in the Southern Hemisphere - Subantarctic climate captures land only on the subantarctic islands and on Graham Land. In the Köppen classification, the subpolar or boreal climate is understood as the climate of the taiga zone.

Polar

Polar climate characterized by year-round negative air temperatures and scant precipitation (100-200 mm per year). It dominates the Arctic Ocean and Antarctica. The mildest in the Atlantic sector of the Arctic, the harshest - on the plateau of East Antarctica. In the Köppen classification, the polar climate includes not only the ice climate zones, but also the climate of the tundra zone.

Climate and man

The climate has a decisive effect on the water regime, soil, flora and fauna, on the possibility of cultivating crops. Accordingly, the possibilities of settling people, the development of agriculture, industry, energy and transport, the living conditions and health of the population depend on the climate. Heat loss by the human body occurs through radiation, heat conduction, convection and evaporation of moisture from the surface of the body. With a certain increase in these heat losses, a person experiences unpleasant sensations and the possibility of illness appears. In cold weather, these losses increase, dampness and strong winds increase the cooling effect. During weather changes, stress becomes more frequent, appetite worsens, biorhythms are disrupted and resistance to diseases decreases. The climate determines the binding of diseases to certain seasons and regions, for example, pneumonia and influenza are sick mainly in winter in temperate latitudes, malaria occurs in the humid tropics and subtropics, where climatic conditions favor the reproduction of malaria mosquitoes. The climate is also taken into account in health care (resorts, epidemic control, public hygiene), and affects the development of tourism and sports. According to information from the history of mankind (famine, floods, abandoned settlements, migrations of peoples), it is possible to restore some of the climatic changes of the past.

Anthropogenic change in the environment of functioning of the climate-forming processes changes the nature of their course. Human activities have a significant impact on the local climate. The influx of heat from fuel combustion, pollution by industrial products and carbon dioxide, which alter the absorption of solar energy, cause an increase in air temperature, which is noticeable in large cities. Among the anthropogenic processes that have assumed a global character are

see also

Notes (edit)

1. (unspecified) ... Archived April 4, 2013.
2. , p. 5.
3. Local climate //: [in 30 volumes] / Ch. ed. A.M. Prokhorov
4. Microclimate // Great Soviet Encyclopedia: [in 30 volumes] / Ch. ed. A.M. Prokhorov... - 3rd ed. - M.: Soviet Encyclopedia, 1969-1978.

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

The climate has an impact on living and inanimate nature. Water bodies, soil, vegetation, animals are closely dependent on the climate. Certain sectors of the economy, primarily agriculture, are also highly dependent on the climate.

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

The geographic latitude of the area determines the angle of incidence of the sun's rays, the receipt of a certain amount of heat. However, getting heat from the Sun also depends on proximity to the ocean... In places far from the oceans, there is little precipitation, and the mode of precipitation is uneven (more in the warm period than in the cold), the cloud cover is low, the winter is cold, the summer is warm, the annual temperature range is large. This climate is called continental because it is typical for places located in the interior of the continents. Above the water surface, a maritime climate is formed, which is characterized by: a smooth course of air temperature, with small daily and annual temperature ranges, large cloud cover, uniform and sufficiently large amount of atmospheric precipitation.

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

An important role in the formation of the climate belongs relief... You already know that as the terrain rises, the air temperature decreases by 5-6 ° С for every kilometer. Therefore, on the high mountain slopes of the Pamirs, the average annual temperature is 1 ° C, although it is located slightly north of the tropic.

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

The climate is also dependent on prevailing winds... On the territory of the East European Plain, westerly winds, coming from the Atlantic Ocean, prevail for almost the entire year, therefore winters in this area are relatively mild.

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

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

Climatic zones

Long-term average values ​​of meteorological elements (annual, seasonal, monthly, daily, etc.), their sums, frequency of occurrence, etc. are called climatic norms: the corresponding values ​​for individual days, months, years, etc. are considered as deviations from these norms.

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

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

The main climatic zones are:

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

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

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

The variety of climates on Earth

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

Arctic and Antarctic climatic zones

Antarctic and arctic climate dominates in Greenland and Antarctica, where average monthly temperatures are below 0 ° C. In the dark winter season, these regions do not receive any 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 ice. Both summer and winter, the elevated regions of the Antarctic Ice Sheet are characterized by low temperatures. The climate of the interior of Antarctica is much colder than the climate of the Arctic, since the southern continent is large and high, and the Arctic Ocean softens the climate, despite the widespread distribution of pack ice. In summer, during short warmings, drifting ice sometimes melts. Precipitation on ice sheets falls in the form of snow or small particles of ice fog. The interior regions receive only 50-125 mm of precipitation annually, but more than 500 mm can fall on the coast. Sometimes cyclones bring clouds and snow to these areas. Snowfalls are often accompanied by strong winds that carry significant amounts of snow, blowing it off the slope. Strong katabatic winds with blizzards blow from the cold ice sheet, carrying snow to the coast.

Table 1. Climates of the Earth

Climate type	Climatic belt	Average temperature, ° С		Mode and amount of atmospheric precipitation, mm	Circulation of the atmosphere	Territory
Equatorial	Equatorial			During a year. 2000	In the area of ​​low atmospheric pressure, warm and humid equatorial air masses are formed	Equatorial regions of Africa, South America and Oceania
Tropical monsoon	Subequa-torial			Mostly during the summer monsoon, 2000		South and Southeast Asia, West and Central Africa, Northern Australia
Tropical dry	Tropical			Throughout the year, 200		North Africa, Central Australia
Mediterranean	Subtropical			Mainly in winter, 500	In summer - anticyclones at high atmospheric pressure; in winter - cyclonic activity	Mediterranean, Southern coast of Crimea, South Africa, Southwestern Australia, Western California
Subtropical dry	Subtropical			During a year. 120	Dry continental air masses	Inner parts of the continents
Moderate marine	Moderate			During a year. 1000	Westerly winds	Western Eurasia and North America
Moderate continental	Moderate			During a year. 400	Westerly winds	Inner parts of the continents
Moderate monsoon	Moderate			Mainly during the summer monsoon, 560		Eastern edge of Eurasia
Subarctic	Subarctic			Throughout the year, 200	Cyclones prevail	Northern outskirts of Eurasia and North America
Arctic (antarctic)	Arctic (Antarctic)			Throughout the year, 100	Anticyclones prevail	Arctic Ocean and mainland Australia

Subarctic continental climate formed in the north of the continents (see the climatic map of the atlas). In winter, arctic air prevails here, which forms in areas of high pressure. Arctic air spreads from the Arctic to the eastern regions of Canada.

Continental subrctic climate Asia is characterized by the largest annual amplitude of air temperature on the globe (60-65 ° С). The continentality of the climate here reaches its maximum value.

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

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

The climate of the subarctic zone of North America is less continental compared to the corresponding climate in Asia. There are less cold winters and colder summers.

Moderate climatic zone

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

The constant transport of sea air is accompanied by large clouds and causes protracted springs, in contrast to the interior of the continental regions of Eurasia.

Winter in temperate the western coasts are warm. The warming influence of the oceans is enhanced by warm sea currents washing the western shores of the continents. The average temperature in January is positive and varies across the territory from north to south from 0 to 6 ° С. During incursions of the Arctic air, it can go down (on the Scandinavian coast to -25 ° С, and on the French coast - to -17 ° С). When tropical air spreads to the north, the temperature rises sharply (for example, it often reaches 10 ° C). In winter, on the western coast of Scandinavia, there are large positive temperature deviations from the average latitudinal temperature (by 20 ° C). The temperature anomaly on the Pacific coast of North America is less and does not exceed 12 ° C.

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

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

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

Moderate climate of the eastern coasts of the continents has monsoon features and is accompanied by a seasonal change of winds: in winter, northwestern flows prevail, in summer - southeastern ones. It is well defined on the east coast of Eurasia.

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

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

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

The Canadian anticyclone, in contrast to the Asian, is unstable. It forms off the coast and is often interrupted by cyclones. Winters are mild, snowy, wet and windy here. In snowy winters, the height of snowdrifts reaches 2.5 m. With a southerly wind, ice often occurs. Therefore, some streets in some cities in eastern Canada have iron railings for pedestrians. Summers are cool and rainy. Annual precipitation is 1000 mm.

Moderate continental climate most clearly expressed on the Eurasian continent, especially in the regions of Siberia, Transbaikalia, northern Mongolia, as well as in the Great Plains in North America.

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

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

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

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

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

The wide front of Eurasia and North America facing the Arctic basin contributes to the deep penetration of cold air masses to the continents throughout the year. Intense meridional air mass transfer is especially characteristic of North America, where arctic and tropical air often replace each other.

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

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

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

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

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

In North America, continental air is somewhat colder in summer than in Asia and Europe. This is due to the lesser extent of the continent in latitude, the large indentedness of its northern part with bays and fjords, the abundance of large lakes, and the more intense development of cyclonic activity in comparison with the inner regions of Eurasia.

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

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

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

Subtropical climate zone

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

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

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

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

Humid subtropical climate characteristic of the eastern coasts of the continents to the 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 province in South Africa and the east coast of Australia. Summers in the humid subtropics are long and hot, with the same temperatures as in the tropics. The average temperature of the warmest month exceeds +27 ° С, and the maximum temperature is +38 ° С. Winters are mild, with average monthly temperatures above 0 ° C, but occasional frosts have a detrimental effect on vegetable and citrus plantations. In humid subtropics, the average annual precipitation ranges from 750 to 2000 mm, the distribution of precipitation over the seasons is quite even. In winter, rains and occasional snowfalls are brought mainly by cyclones. In summer, precipitation falls mainly in the form of thunderstorms associated with powerful inflows of warm and humid oceanic air, characteristic of the monsoon circulation of East Asia. Hurricanes (or typhoons) occur in late summer and fall, especially in the Northern Hemisphere.

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

Equatorial climate zone

Equatorial type of climate distributed in equatorial latitudes in the Amazon basins in South America and Congo in Africa, on the Malacca Peninsula and on the islands of Southeast Asia. Typically, the average annual temperature is about +26 ° С. Due to the high noon standing of the Sun above the horizon and the same day length throughout the year, seasonal temperature fluctuations are small. Humid air, cloudiness and dense vegetation prevent nighttime cooling and maintain maximum daytime temperatures below +37 ° C, lower than in higher latitudes. Average annual rainfall in the humid tropics ranges from 1,500 to 3,000 mm and is usually evenly distributed over the seasons. Precipitation is mainly associated with the intertropical convergence zone, which is located slightly north of the equator. Seasonal displacements of this zone to the north and south in some areas lead to the formation of two maximum precipitation during the year, separated by drier periods. Thousands of thunderstorms roll over the humid tropics every day. In between, the sun shines in full force.

Chapter III

Climatic characteristics of the seasons of the year

Seasons of the year

Under the natural climatic season. it should be understood the period of the year, characterized by the same type of code of meteorological elements and a certain thermal regime. The calendar boundaries of such seasons in general do not coincide with the calendar boundaries of the months and to a certain extent are conditional. The end of this season and the beginning of the next one can hardly be fixed with a specific date. This is a certain period of time of the order of several days, during which there is a sharp change in atmospheric processes, radiation regime, physical properties of the underlying surface and weather conditions.

The average long-term boundaries of the seasons can hardly be tied to the average long-term dates of the transition of the average daily temperature through certain limits, for example, the summer is counted from the day the average daily temperature reaches above 10 ° during the period of its increase, and the end of summer - from the date of the onset of the average daily temperature below 10 ° during the period of its decline, as suggested by A. N. Lebedev and G. P. Pisareva.

In the conditions of Murmansk, located between the vast continent and the water area of ​​the Barents Sea, when dividing the year into seasons, it is advisable to be guided by the differences in temperature regime over land and sea, which depends on the conditions for the transformation of air masses over the underlying surface. These differences are most significant in the period from November to March, when the air masses over the Barents Sea are warming up and over the mainland are cooled, and from June to August, when the transformations of air masses over the mainland and sea water area are opposite to those in winter. In April and May, as well as in September and October, the temperature differences between sea and continental air masses are smoothed out to a certain extent. Differences in the temperature regime of the lower air layer above land and sea form in the Murmansk region significant in absolute value meridional temperature gradients in the coldest and warmest periods of the year. In the period from November to March, the average value of the meridional component of the horizontal temperature gradient reaches 5.7 ° / S0 km with the direction of the gradient to the south, towards the mainland, from June to August - 4.2 ° / 100 km, towards the north, towards seas. In intermediate periods, the absolute value of the meridional component of the horizontal temperature gradient decreases to 0.8 ° / 100 km from April to May and to 0.7 ° / 100 km from September to October.

Temperature differences in the lower air layer over the sea and the mainland form other temperature characteristics. These characteristics include the average value of the monthly variability of the average daily air temperature, which depends on the direction of advection of air masses and partly changes in the transformation conditions from one day to another of the surface air layer with clearing or increasing cloudiness, increasing wind, etc. - daily variability of air temperature in Murmansk conditions:

From November to March, in any of the months, the average monthly value of the day-to-day temperature variability is higher than the average annual, from June to August it is approximately 2.3 °, i.e., it is close to the average annual, and in the remaining months it is below the average annual. Consequently, the seasonal values ​​of this temperature characteristic confirm the above division of the year into seasons.

According to L.N. Vodovozova, cases with sharp fluctuations in temperature values ​​from a given day to the next (> 10 °) are most likely in winter (November-March) - 74 cases, somewhat less likely in summer (June-August) -43 cases and the least likely in transitional seasons: in spring (April-May) -9 and in autumn (September-October) - only 2 cases in 10 years. This division also confirms the fact that sharp fluctuations in temperature are largely associated with a change in the direction of advection, and, consequently, with temperature differences between land and sea. The average monthly temperature for a given wind direction is no less indicative for dividing the year into seasons. This value, obtained over a limited observation period, over only 20 years, with a possible error of the order of 1 °, which in this case can be neglected, for two wind directions (the southern quarter from the mainland and the northern quarter from the sea) is given in Table. 36.

The average difference in air temperature, according to table. 36, changes sign in April and October: from November to March it reaches -5 °. from April to May and from September to October - only 1.5 °, and from June to August it increases to 7 °. A number of other characteristics can be cited that are directly or indirectly related to temperature differences over the mainland and the sea, but it can already be considered obvious that the period from November to March should be attributed to the winter season, from June to August - to the summer season, April and May-- to spring, and September and October to autumn.

The definition of the winter season closely coincides with the average length of the period of persistent frost, which begins on November 12 and ends on April 5. The beginning of the spring season coincides with the beginning of radiation thaws. The average maximum temperature in April goes over 0 °. The average maximum temperature in all summer months is> 10 °, and the minimum is> 5 °. The beginning of the autumn season coincides with the earliest date of the onset of frost, the end - with the onset of persistent frost. During spring, the average daily temperature rises by 11 °, and during autumn it decreases by 9 °, that is, the increase in temperature during the spring and its decrease during the fall reaches 93% of the annual amplitude.

Winter

The beginning of the winter season coincides with the average date for the formation of stable snow cover (November 10) and the beginning of the period with stable frost (November 12). The formation of a snow cover causes a significant change in the physical properties of the underlying surface, thermal and radiation conditions of the surface air layer. The average air temperature passes through 0 ° a little earlier, even in the fall (October 17), and in the first half of the season its further decrease continues: the transition through -5 ° on November 22 and through -10 ° on January 22. January and February are the coldest months of winter. From the second half of February, the average temperature begins to rise and on February 23 passes through -10 °, and at the end of the season, on March 27 - through -5 °. In winter, on clear nights, severe frosts are possible. Absolute minimums reach -32 ° in November, -36 ° in December and January, -38 ° in February and -35 ° in March. However, such low temperatures are unlikely. The minimum temperature below -30 ° is observed in 52% of years. It is most rarely observed in November (2% of years) and March (4%)< з наиболее часто - в феврале (26%). Минимальная температура ниже -25° наблюдается в 92% лет. Наименее вероятна она в ноябре (8% лет) и марте (18%), а наиболее вероятна в феврале (58%) и январе (56%). Минимальная температура ниже -20° наблюдается в каждом сезоне, но ежегодно только в январе. Минимальная температура ниже -15° наблюдается в течение всего сезона и в январе ежегодно, а в декабре, феврале и марте больше чем в 90% лет и только в ноябре в 6% лет. Минимальная температура ниже -10° возможна ежегодно в любом из зимних месяцев, кроме ноября, в котором она наблюдается в 92% лет. В любом из зимних месяцев возможны оттепели. Максимальные температуры при оттепели могут достигать в ноябре и марте 11°, в декабре 6° и в январе и феврале 7°. Однако такие высокие температуры наблюдаются очень редко. Ежегодно оттепель бывает в ноябре. В декабре ее вероятность составляет 90%, в январе 84%, в феврале 78% и в марте 92%. Всего за зиму наблюдается в среднем 33 дня с оттепелью, или 22% общего числа дней в сезоне, из них 13,5 дня приходится на ноябрь, 6,7 на декабрь, 3,6 на январь, 2,3 на февраль и 6,7 на март. Зимние оттепели в основном зависят от адвекции теплых масс воздуха из северных районов, реже из центральных районов Атлантики и наблюдаются обычно при большой скорости ветра. В любом из зимних месяцев средняя скорость ветра в период оттепелей больше среднего значения за весь месяц. Наиболее вероятны оттепели при западных направлениях ветра. При уменьшении облачности и ослаблении ветра оттепель обычно прекращается.

Twenty-four-hour thaws are rare, only about 5 days per season: 4 days in November and one in December. In January and February, round-the-clock thaws are possible no more than 5 days in 100 years. Winter advective thaws are possible at any time of the day. But in March, daytime thaws already predominate and the first radiation thaws are possible. However, the latter are observed only against the background of a relatively high average daily temperature. Depending on the prevailing development of atmospheric processes in any of the months, significant anomalies of the average monthly air temperature are possible. So, for example, with an average long-term air temperature in February equal to -10.1 °, the average temperature in February in 1959 reached -3.6 °, i.e. it was 6.5 ° above the norm, and in 1966 decreased to -20.6 °, that is, it was below the norm by 10.5 °. Similar significant air temperature anomalies are possible in other months.

Abnormally high average monthly air temperatures in winter are observed during intense cyclonic activity in the north of the Norwegian and Barents Seas with stable anticyclones over Western Europe and the European territory of the USSR. Cyclones from Iceland in abnormally warm months move northeast through the Norwegian Sea to the north of the Barents Sea, from there to the southeast to the Kara Sea. In the warm sectors of these cyclones, very warm masses of Atlantic air are carried to the Kola Peninsula. Occasional incursions of the Arctic air do not cause significant cooling, since, passing over the Barents or Norwegian Sea, the Arctic air warms up from below and does not have time to cool down on the mainland with short clearings in rapidly moving ridges between individual cyclones.

The winter of 1958-59, which was warmer than the norm by almost 3 ° C, can be classified as anomalously warm. This winter there were three very warm months: November, February and March, only December was cold and January was close to normal. February 1959 was especially warm. There was no such warm February over the years of observations, not only in Murmansk since 1918, but also at st. Cola since 1878, i.e. for 92 years. In this February, the average temperature exceeded the norm by more than 6 °, there were 13 days with thaw, that is, more than 5 times more than the average long-term values. The trajectories of cyclones and anticyclones are shown in Fig. 19, from which it can be seen that throughout the month cyclones moved from Iceland through the Norwegian and Barents Seas, carrying warm Atlantic air to the north of the European territory of the USSR, anticyclones from west to east along more southern trajectories than in ordinary years. February 1959 was anomalous not only in temperature, but also in a number of other meteorological elements. Deep cyclones over the Barents Sea caused frequent storms this month. The number of days with strong winds ≥ 15 m / s. reached 13, that is, it exceeded the norm by almost three times, and the average monthly wind speed exceeded the norm by 2 m / sec. Due to the frequent passage of the fronts, the cloud cover also exceeded the norm. For the whole month, there was only one clear day with low cloudiness at a norm of 5 days and 8 cloudy at a norm of 6 days. Similar anomalies of other meteorological elements were observed in the anomalously warm March 1969, the average temperature of which exceeded the multiyear average by more than 5 °. In December 1958 and January 1959 a lot of snow fell. However, by the end of winter, it almost completely melted. Table 37 presents observational data in the second half of winter 1958-59, from which it can be seen that the transition of the average temperature through -10 ° during the period of its increase was carried out 37 days earlier than usual, and after -5 ° - by 47 days.

Of the exceptionally cold winters over the observation period in Murmansk since 1918 and at Kola station since 1888, the winter 1965-66 can be indicated. That winter the average seasonal temperature was almost 6 ° lower than the long-term average for this season. The coldest months were February and March. Months as cold as February and March 1966 have not been observed in the last 92 years. In February 1966, as can be seen from Fig. 20, the trajectories of cyclones were located south of the Kola Peninsula, and anticyclones were located over the extreme northwest of the European territory of the USSR. Occasional inflows of continental Arctic air from the Kara Sea were observed, which also caused significant and persistent cooling.

The anomaly in the development of atmospheric processes in February 1966 caused an anomaly not only in air temperature, but also in other meteorological elements. The prevalence of anticyclonic weather resulted in a decrease in cloudiness and wind speed. Thus, the average wind speed reached 4.2 m / s, or was below the norm by 2.5 m / s. There were 8 clear days with low clouds this month at a rate of 6 and only one cloudy day at the same rate. During December, January, February, there was not a single day with a thaw. The first thaw was observed only on March 31. In normal years, from December to March, there are about 19 days with a thaw. The Kola Bay is covered with ice very rarely and only in extremely cold winters. In the winter of 1965-66, a long-term continuous ice cover was established in the Kola Bay in the Murmansk region: once in February and once in March *, while discontinuous, thin ice with streaks was observed in most of February and March, and sometimes even in April.

The transition of the average temperature through -5 and -10 ° during the cooling period in the winter of 1965-66 was carried out earlier than usual by 11 and 36 days, and during the warming through the same limits with a delay against the norm by 18 and 19 days. A stable transition of the average temperature through -15 ° and the duration of the period with temperatures below this limit reached 57 days, which is very rare. A steady cooling with the transition of the average temperature through -15 ° is observed on average only 8% of winters. In the winter of 1965-66, anti-diclonic weather prevailed not only in February, but throughout the entire season.

The prevalence of cyclonic processes over the Norwegian and Barents Seas and anticyclonic processes over the mainland in ordinary winters determines the prevalence of wind (from the mainland) of the southern southeastern and southwestern directions. The total frequency of these wind directions reaches 74% in November, 84% in December, 83% in January, 80% in February and 68% in March. The frequency of opposite wind directions from the sea is much less, and it is 16% in November, 11% in December and January, 14% in February and 21% in March. With the southerly direction of the wind of the highest frequency, the lowest average temperatures are observed, and with the northerly direction, which is much less likely in winter, the highest. Therefore, in winter, the south side of buildings loses more heat than the north. An increase in the frequency and intensity of cyclones leads to an increase in both the average wind speed and the frequency of storms in winter. Average seasonal wind speed in winter is 1 m / s. above the annual average, and the highest, about 7 m / sec., falls on the middle of the season (January). Number of days with storm ≥ 15 m / s. reaches 36 or 67% of their annual value in winter; in winter, the wind may increase up to a hurricane ≥ 28 m / s. However, hurricanes in Murmansk are unlikely in winter, when they are observed once every 4 years. The most probable storms are south and southwest. Possibility of light wind< 6 м/сек. колеблется от 44% в феврале до 49% в марте, а в среднем за сезон достигает 46%- Наибольшая облачность наблюдается в начале сезона, в ноябре. В течение сезона она постепенно уменьшается, достигая минимума в марте, который является наименее облачным. Наличие значительной облачности во время полярной ночи сокращает и без того короткий промежуток сумеречного времени и увеличивает неприятное ощущение, испытываемое во время полярной ночи.

The coldest temperatures in winter cause a decrease in both the absolute moisture content and the lack of saturation. The daily variation of these humidity characteristics in winter is practically absent, while the relative air humidity during the first three months of winter, from November to January, reaches an annual maximum of 85%, and from February it decreases to 79% in March. In most of winter, until February inclusive, daily periodic fluctuations in relative humidity, confined to a certain time of day, are absent and become noticeable only in March, when their amplitude reaches 12%. Dry days with a relative humidity of ≤30% at least for one of the observation periods in winter are completely absent, and wet days with a relative humidity of ≥80% at 13:00 prevail and are observed on average in 75% of the total number of days in the season. A noticeable decrease in the number of wet days is observed at the end of the season, in March, when the relative humidity decreases during the daytime due to warming up of the air.

Precipitation occurs in winter more often than in other seasons. On average, there are 129 days with precipitation per season, which is 86% of all days of the season. However, precipitation in winter is less intense than in other seasons. The average amount of precipitation per day with precipitation is only 0.2 mm in March and 0.3 mm for the rest of the months from November to February inclusive, while their average duration per day with precipitation fluctuates around 10 hours in winter. In 52% of the total number of days with precipitation, their amount does not even reach 0.1 mm. Often, light snow falls with short interruptions over a number of days, without causing an increase in snow cover. Significant precipitation ≥ 5 mm per day is observed in winter quite rarely, only 4 days per season, and even more intense precipitation over 10 mm per day is very unlikely, only 3 days in 10 seasons. The greatest daily amount of precipitation * kov is observed in winter with precipitation "charges". The curtain of the winter season receives an average of 144 mm of precipitation, which is 29% of their annual amount. The greatest amount of precipitation falls in November, 32 mm, and the least - in March, 17 mm.

In winter, solid precipitation in the form of snow predominates. Their share of the total for the entire season is 88%. Mixed precipitation in the form of snow with rain or sleet falls much less often and their share is only 10% of the total for the entire season. Liquid precipitation in the form of rain is even less likely. The share of liquid precipitation does not exceed 2% of their total seasonal amount. Liquid and mixed precipitation is most probable (32%) in November, in which thaws are most frequent, the least probable is January (2%).

In some months, depending on the frequency of cyclones and synoptic positions characteristic of precipitation with charges, their monthly amount can vary within wide limits. December 1966 and January 1967 can be cited as an example of significant anomalies in the monthly precipitation amount. The circulating conditions of these months are described by the author in his work. In December 1966, only 3 mm of precipitation fell in Murmansk, which is 12% of the average long-term amount for that month. The depth of the snow cover during December 1966 was less than 1 cm, and in the second half of the month there was virtually no snow cover. In January 1967, the monthly precipitation reached 55 mm, or 250% of the long-term average, and the maximum daily amount reached 7 mm. In contrast to December 1966, January 1967 saw frequent precipitation by charges, accompanied by strong winds and snowstorms. This caused frequent snow drifts, which impeded the work of transport.

In winter, all atmospheric phenomena are possible, except for hail. The average number of days with various atmospheric phenomena is given in table. 38.

From the data table. 38 it can be seen that evaporation fog, blizzard, fog, rime, ice and snow have the greatest recurrence in the winter season, and therefore are typical for it. Most of the specified winter weather conditions (evaporation fog, blizzard, fog and snowfall) impair visibility. These phenomena are associated with a deterioration in visibility in the winter season compared to other seasons. Practically all atmospheric phenomena characteristic of winter often cause serious difficulties in the work of various branches of the national economy. Therefore, the winter season is the most difficult for the production activities of all sectors of the national economy.

Due to the short duration of the day, the average number of hours of sunshine in winter during the first three months of winter, from November to January, does not exceed 6 hours, and in December, during the polar night, the sun is not observed throughout the month. At the end of winter, due to the rapid increase in the length of the day and the decrease in cloud cover, the average number of hours of sunshine increases to 32 in February and to 121 hours in March.

Spring

An increase in the frequency of daytime radiation thaws is a characteristic sign of the beginning of spring in Murmansk. The latter are noted already in March, but in March they are observed during the daytime only at relatively high average daily temperatures and with slight frosts at night and in the morning. In April, with clear or slightly cloudy and quiet weather, daytime thaws are possible with a significant cold snap at night, up to -10, -15 °.

A significant rise in temperature is observed during the spring. So, on April 24, the average temperature, rising, goes through 0 °, and on May 29, through 5 °. In cold springs, these dates may be late, and in warm ones, they may be ahead of the average multi-year dates.

In spring, on cloudless nights, in the masses of cold Arctic air, a significant decrease in temperature is still possible: to -26 ° in April and to -11 ° in May. With the advection of warm air from the mainland or from the Atlantic in April, the temperature can reach 16 °, and in May + 27 °. In April, on average, up to 19 days with a thaw are observed, of which 6 with a thaw throughout the day. In April, with winds from the Barents Sea and significant cloud cover, an average of 11 days without thaw are observed. In May, thaws are observed even more often for 30 days, of which, in 16 days, frost is completely absent throughout the day.

Twenty-four-hour frosty weather without a thaw in May is very rare, on average one day a month.

In May, there are already hot days with a maximum temperature of over 20 °. But hot weather in May is still a rare phenomenon, possible in 23% of years: on average, this month there are 4 hot days in 10 years, and then only with the wind from the south and south-west directions.

The average monthly air temperature from March to April rises by 5.3 ° and reaches -1.7 ° in April, and from April to May by 4.8 ° and reaches 3.1 ° in May. In some years, the average monthly temperature of the spring months can differ significantly from the norm (long-term average). For example, the average long-term temperature in May is 3.1 °. In 1963, it reached 9.4 °, that is, it exceeded the norm by 6.3 °, and in 1969 it dropped to 0.6 °, that is, it was below the norm by 2.5 °. Similar anomalies of the mean monthly temperature are possible in April.

The spring of 1958 was rather cold. The average temperature in April was 1.7 ° below normal, and in May - by 2.6 °. The transition of the average daily temperature through -5 ° was carried out on April 12 with a delay of 16 days, and after 0 ° only on May 24 with a delay of 28 days. May 1958 was the coldest for the entire observation period (52 years). Cyclone trajectories, as seen from Fig. 21, passed south of the Kola Peninsula, and anticyclones prevailed over the Barents Sea. This trend in the development of atmospheric processes led to the predominance of advection of cold masses of Arctic air from the Barents, and sometimes from the Kara Sea.

The highest frequency of occurrence of wind in various directions in the spring of 1958, according to Fig. 22, was observed for the winds of the northeastern, eastern and southeastern directions, with which the coldest continental arctic air usually enters Murmansk from the Kara Sea. This causes significant cooling in winter and especially in spring. In May 1958, there were 6 days without a thaw at a rate of one day, 14 days with an average daily temperature<0° при норме 6 дней, 13 дней со снегом и 6 дней с дождем. В то время как в обычные годы наблюдается одинаковое число дней с дождем и снегом. Снежный покров в 1958 г. окончательно сошел только 10 июня, т. е. с опозданием по отношению к средней дате на 25 дней.

The spring of 1963 can be indicated as warm, when April and especially May were warm. The average air temperature in the spring of 1963 went over 0 ° on April 17, 7 days earlier than usual, and after 5 ° - on May 2, that is, 27 days earlier than usual. May was especially warm in the spring of 1963. Its average temperature reached 9.4 °, that is, it exceeded the norm by more than 6 °. There has never been such a warm May as in 1963 for the entire observation period of Murmansk station (52 years).

In fig. 23 shows the trajectories of cyclones and anticyclones in May 1963. As can be seen from Fig. 23, anticyclones prevailed over the European territory of the USSR throughout May. During the whole month Atlantic cyclones moved north-east through the Norwegian and Barents Seas, carrying very warm continental air from the south to the Kola Peninsula. This is clearly seen from the data in Fig. 24. The frequency of occurrence of the warmest wind for spring in the southern and southwestern directions in May 1963 exceeded the multiyear average. In May 1963, there were 4 hot days, which are observed on average 4 times in 10 years, 10 days with an average daily temperature> 10 ° at a rate of 1.6 days and 2 days with an average daily temperature> 15 ° at a rate of 2 days per 10 years. The anomaly in the development of atmospheric processes in May 1963 caused anomalies in a number of other characteristics of the climate. The average monthly relative humidity was 4% below the norm, clear days were 3 days more than the norm, and cloudy - 2 days less than the norm. Warm weather in May 1963 caused an early melting of the snow cover, at the end of the first ten days of May, i.e. 11 days earlier than usual.

During spring, a significant restructuring of the frequency of different wind directions is observed.

In April, the winds of the southern and southwestern directions still prevail, the frequency of which is 26% higher than the frequency of the winds in the northern and northwestern directions. And in May, northerly and north-westerly winds are observed 7% more often than south and south-westerly ones. A sharp increase in the frequency of the wind direction from the Barents Sea from April to May causes an increase in cloudiness in May, as well as returns of cold weather, often observed in early May. This is clearly seen from the data of the average ten-day temperature (Table 39).

From the first to the second and from the second to the third decade of April, a more significant increase in temperature is observed than from the third decade of April to the first decade of May; the most probable decrease in temperature is from the third ten-day period of April to the first ten-day period of May. Such a change in successive ten-day temperatures in spring indicates that spring returns are most likely in early May and, to a lesser extent, in the middle of this month.

Average monthly wind speed and number of days with wind ≥ 15 m / s. during the spring they noticeably decrease.

The most significant change in wind speed characteristics is observed in early spring (in April). In the speed and direction of the wind in spring, especially in May, the diurnal frequency also begins to be traced. Thus, the daily amplitude of the wind speed increases from 1.5 m / s. in April up to 1.9 m / sec. in May, and the amplitude of the frequency of wind directions from the Barents Sea (north, north-west and north-east) increases from 6% in April to 10% in May.

In connection with the rise in temperature, the relative humidity decreases in spring from 74% in April to 70% in May. An increase in the amplitude of the daily fluctuations in air temperature causes an increase in the same amplitude of the relative humidity, from 15% in April to 19% in May. In spring, dry days are already possible with a decrease in relative humidity to 30% and below, at least for one of the observation periods. Dry days in April are still very rare, one day every 10 years, in May they occur more often, 1.4 days annually. The average number of wet days with a relative humidity of ≥ 80% over 13 hours decreases from 7 in April to 6 in May.

An increase in the frequency of advection from the sea and the development of cumulus clouds in the daytime causes a noticeable increase in cloudiness in spring from April to May. Unlike April, in May, due to the development of cumulus clouds, the probability of clear weather in the morning and at night is greater than in the afternoon and evening.

In spring, the diurnal variation of various cloud forms is well traced (Table 40).

Convective clouds (Cu and Cb) are most likely during the day at 12 and 15 hours and are least likely at night. The probability of clouds Sc and St changes during the day in the opposite order.

In spring, an average of 48 mm of precipitation falls out (according to the precipitation meter), of which 20 mm in April and 28 mm in May. In some years, the amount of precipitation in both April and May may differ significantly from the long-term average. According to the data of precipitation gauging observations, the amount of precipitation in April fluctuated in some years from 155% of the norm in 1957 to 25% of the norm in 1960, and in May from 164% of the norm in 1964 to 28% of the norm in 1959. The deficit of precipitation in spring is caused by the predominance of anticyclonic processes, and the excess is caused by the increased frequency of southern cyclones passing through or near Murmansk.

The intensity of precipitation also noticeably increases in spring, hence the maximum amount of precipitation falling per day. So, in April, the daily precipitation of ≥ 10 mm is observed once every 25 years, and in May, the same amount of precipitation is much more often - 4 times in 10 years. The highest daily precipitation reached 12 mm in April and 22 mm in May. In April and May, significant daily rainfall occurs with heavy rain or snow. Heavy rainfall in spring does not yet provide a large amount of moisture, since they are usually short-lived and not yet intense enough.

In spring, precipitation falls in the form of solid (snow), liquid (rain) and mixed (rain and snow and sleet). In April, solid precipitation still predominates, 61% of the total amount, 27% falls on the share of mixed precipitation, and only 12% - on the share of liquid. In May, liquid precipitation predominates, accounting for 43% of the total, 35% of mixed precipitation and least of all solid precipitation, only 22% of the total. However, in April and May, the largest number of days falls on solid precipitation, and the smallest in April, on liquid precipitation, and in May, on mixed precipitation. This discrepancy between the largest number of days with solid precipitation and the smallest share in the total amount in May is explained by the greater intensity of rain compared to snowfall. The average date for the destruction of snow cover is May 6, the earliest is April 8, and the average date of snow cover is May 16, the earliest is April 17. In May, after heavy snowfall, the snow cover can still form, but not for long, since the snow that has fallen in the daytime melts. In spring, all atmospheric phenomena that are possible in winter are still observed (Table 41).

All atmospheric phenomena, except for various types of precipitation, have a very low frequency of occurrence in spring, the lowest in a year. The frequency of harmful phenomena (fog, blizzard, evaporation fog, ice and frost) is much less than in winter. Atmospheric phenomena such as fog, frost, evaporation fog and ice in the spring are usually destroyed during the daytime. Therefore, harmful atmospheric phenomena do not cause serious difficulties for the operation of various sectors of the national economy. Due to the low frequency of fogs, heavy snowfalls and other phenomena that worsen horizontal visibility, the latter noticeably improves in spring. The probability of poor visibility less than 1 km decreases to 1% in April and to 0.4% of the total number of observations in May, and the probability of good visibility over> 10 km increases to 86% in April and 93% in May.

Due to the rapid increase in the length of the day in spring, the duration of sunshine also increases from 121 hours in March to 203 hours in April. However, in May, due to the increase in cloudiness, despite the increase in the length of the day, the number of hours of sunshine even slightly decreases to 197 hours. The number of days without sun also slightly increases in May compared to April, from three in April to four in May.

Summer

A characteristic feature of summer, like winter, is an increase in temperature differences between the Barents Sea and the mainland, causing an increase in the day-to-day variability of air temperature, depending on the direction of the wind - from land or from the sea.

The average maximum air temperature from June 2 to the end of the season and the average daily temperature from June 22 to August 24 are kept above 10 °. The beginning of summer coincides with the beginning of the frost-free period, on average June 1, and the end of summer - with the earliest end of the frost-free period, September 1.

Frosts in summer are possible until June 12 and then stop until the end of the season. During a 24-hour day, advective frosts prevail, which are observed in cloudy weather, snowfall and strong winds, radiation frosts on sunny nights are less common.

During most of the summer, average daily air temperatures prevail from 5 to 15 °. Hot days with maximum temperatures above 20 ° are not often observed, on average 23 days for the entire season. In July, the warmest summer month, hot days 1 are observed in 98% of years, in June in 88%, in August in 90%. Hot yugoda is mainly observed with winds from the mainland and is most likely with southerly and southwestern winds. The highest temperature on hot summer days can reach 31 ° in June, 33 ° in July and 29 ° in August. In some years, depending on the prevailing direction of the inflow of air masses from the Barents Sea or the mainland, the average temperature in any of the summer months, especially in July, can vary widely. So, at; average long-term July temperature of 12.4 ° in 1960, it reached 18.9 °, i.e. exceeded the norm by 6.5 °, and in 1968 it dropped to 7.9 °, i.e. was below the norm by 4.5 °. Similarly, the dates of the transition of the average temperature of the air through 10 ° can fluctuate in individual years. The dates of the transition through 10 °, possible once j 20 years (5 and 95% of the probability), may differ by 57 days in the beginning and 49 at the end of the season, and the duration of the period with a temperature> 10 ° of the same probability - for 66 days. There are significant implications in individual years and the number of days with hot weather per month and season.

The warmest summer for the entire observation period was in 1960. The average seasonal temperature for this summer reached 13.5 °, that is,> was 3 ° higher than the long-term average. The warmest this summer was July. There was no such warm month for the entire 52-year observation period in Murmansk and the 92-year observation period at Sola station. In July 1960, there were 24 hot days, the norm being II days. Continuous hot weather persisted from June 30 to July 3. Then, after a short cold snap, from 5 to 20 July, hot weather set in again. From July 21 to 25, the weather was cool, which from July 27 until the end of the month again changed to very hot with maximum temperatures over 30 °. The average daily temperature during the whole month was kept above 15 °, that is, a stable transition of the average temperature through 15 ° was observed.

In fig. 27 shows the trajectories of cyclones and anticyclones, and Fig. 26 the frequency of the wind directions in July 1960. As can be seen from Fig. 25, in July 1960, anticyclones prevailed over the European territory of the USSR, cyclones passed over the Norwegian Sea and Scandinavia in a northern direction and carried very warm continental air to the Kola Peninsula. The predominance of very warm southerly and southwesterly winds in July 1960 is clearly seen from the data in Fig. 26. This month was not only very warm, but also slightly cloudy and dry. The predominance of hot and dry weather caused persistent burning of forests and peat bogs and strong smoke in the air. Due to the smoke of forest fires, even on clear days, the sun barely shone through, and in the morning, night and evening hours it was completely hidden behind a curtain of thick smoke. Because of the hot weather in the fishing port, which was not adapted to work in the conditions of stable hot weather, fresh fish deteriorated.

The summer of 1968 was abnormally cold. The average seasonal temperature this summer was below the norm by almost 2 °, only June was warm, the average temperature of which exceeded the norm by only 0.6 °. July was especially cold, and August was also cold. Such a cold July for the entire observation period in Murmansk (52 years) and at Kola station (92 years) has not yet been noted. The average July temperature was 4.5 ° below normal; for the first time in the entire observation period, there was not a single hot day in Murmansk with a maximum temperature of more than 20 °. Due to the renovation of the heating plant, which is timed to coincide with the end of the heating season, it was very cold and damp in apartments with central heating.

The abnormally cold weather in July, and partly by August 1968, was due to the predominance of very stable advection of cold air from the Barents Sea. As can be seen from Fig. 27 in July 1968, two directions of cyclone movement prevailed: 1) from the north of the Norwegian Sea to the southeast, through Scandinavia, Karelia and further to the east, and 2) from the British Isles, through Western Europe, the European territory of the USSR to the north of Western Siberia. Both main predominant directions of cyclone movement took place south of the Kola Peninsula and, therefore, the advection of Atlantic, and even more so continental air to the Kola Peninsula was absent and the advection of cold air from the Barents Sea prevailed (Fig. 28). The characteristics of the anomalies of meteorological elements in July are given in Table. 42.

July 1968 was not only cold, but wet and cloudy. From the analysis of two anomalous July, it can be seen that the warm summer months are formed due to the high frequency of continental air masses, bringing low-cloud and hot weather, and the cold ones, due to the prevalence of wind from the Barents Sea, bringing cold and cloudy weather.

In summer, northern winds prevail in Murmansk. Their frequency of occurrence for the whole season is 32%, of southern ones - 23%. Just as rarely, as in other seasons, there are east and south-east and west winds. The repeatability of any of these directions is not more than 4%. The most probable are the northerly winds, their frequency in July is 36%, in August it decreases to 20%, that is, already by 3% less than the southerly ones. During the day, the direction of the wind changes. The breeze daily fluctuations in the wind direction are especially noticeable in low-wind, clear and warm weather. However, breeze fluctuations are also well noticeable by the average long-term frequency of the wind direction at different hours of the day. Northerly winds are most likely in the afternoon or evening, southern ones, on the contrary, are most likely in the morning and least likely in the evening.

In summer, the lowest wind speeds are observed in Murmansk. The average speed for the season is only 4.4 m / s, at 1.3 m / s. less than the annual average. The lowest wind speed is observed in August, only 4 m / s. In summer, weak winds of up to 5 m / s are most likely, the probability of such speeds ranges from 64% in July to 72% in August. Strong winds ≥ 15 m / s in summer are unlikely. The number of days with strong winds for the entire season is 8 days, or only about 15% of the annual number. During the day in summer, there are noticeable periodic fluctuations in wind speed. The lowest wind speeds during the whole season are observed at night (1 hour), the highest - during the day (13 hours). The daily amplitude of the wind speed fluctuates in the summer of about 2 m / s, which is 44-46% of the average daily wind speed. Light winds, less than 6 m / s, are most likely at night and least likely during the day. Wind speed ≥ 15 m / s, on the contrary, is the least likely at night and most likely during the day. Most often in summer, strong winds are observed during thunderstorms or heavy rains and are short-lived.

Significant heating of air masses and their humidification due to evaporation from moist soil in summer compared to other seasons causes an increase in the absolute moisture content of the surface air layer. The average seasonal pressure of water vapor reaches 9.3 mb and increases from June to August from 8.0 to 10.6 mb. During the day, fluctuations in the elasticity of water vapor are small, with an amplitude from 0.1 mb in June to 0.2 mb in July and up to 0.4 mb in August. In summer, the lack of saturation also increases, since an increase in temperature causes a faster increase in the moisture capacity of the air in comparison with its absolute moisture content. The average seasonal lack of saturation reaches 4.1 mb in summer, increasing from 4.4 mb in June to 4.6 mb in July and sharply decreasing in August to 3.1 mb. Due to the increase in temperature during the day, there is a noticeable increase in the lack of saturation compared to the night.

Relative air humidity reaches an annual minimum of 69% in June, and then gradually increases to 73% in July and 78% in August.

During the day, fluctuations in the relative humidity of the air are significant. The highest relative air humidity is observed on average after midnight and, therefore, its maximum value coincides with the daily minimum temperature. The lowest relative air humidity is observed on average in the afternoon, at 2 pm or 3 pm, and coincides with the daily maximum temperature. According to hourly data, the daily amplitude of the relative air humidity reaches 20% in June, 23% in July and 22% in August.

Low relative humidity ≤ 30% most likely in June and least likely in August. High relative humidity ≥ 80% and ≥ 90% least likely in June and most likely in August. Summer and dry days with a relative humidity of ≤30% for any observation period are most likely. The average number of such days ranges from 2.4 in June to 1.5 in July and up to 0.2 in August. Wet days with a relative humidity of ≥ 80% RH, even in summer, are more common than dry days. The average number of wet days ranges from 5.4 in June to 8.7 in July and up to 8.9 in August.

In the summer months, all characteristics of relative humidity depend on the air temperature, and therefore on the direction of the wind from the mainland or the Barents Sea.

Cloudiness does not change significantly from June to July, but increases noticeably in August. Due to the development of cumulus and cumulonimbus clouds, an increase in it is observed in the daytime.

The diurnal variation of various cloud forms in summer is traced as well as in spring (Table 43).

Cumulus clouds are possible in the interval from 9 to 18 hours and have a maximum recurrence of about 15 hours. Cumulonimbus clouds are least likely in summer at 3 o'clock, most likely, as well as cumulus, around 15 o'clock. Stratocumulus clouds, which form during the decay of powerful cumulus clouds in summer, are most likely around noon and least likely at night. Stratus clouds, carried out in summer from the Barents Sea, as raised fog, are most likely at 6:00, and the least likely at 15:00.

Precipitation in the summer months occurs mainly as rain. Wet snow does not fall every year, only in June. In July and August, wet snow is observed very rarely, once every 25-30 years. The smallest amount of precipitation (39 mm) falls in June. Subsequently, the monthly amount of precipitation increases to 52 in July and to 55 in August. Thus, in the summer season, about 37% of the annual precipitation falls.

In some years, depending on the frequency of cyclones and anticyclones, the monthly precipitation can vary significantly: in June from 277 to 38% of the norm, in July from 213 to 35%, and in August from 253 to 29%.

The excess of precipitation in the summer months is due to the increased frequency of occurrence of southern cyclones, and the deficit is due to stable anticyclones.

Over the entire summer season, an average of 46 days are observed with precipitation up to 0.1 mm, of which 15 days are in June, 14 in July and 17 in August. Significant precipitation with an amount of ^ 10 mm per day rarely falls, but more often than in other seasons. In total, during the summer season, an average of about 4 days is observed with daily precipitation of ^ 10 mm and one day with precipitation of ^ 20 mm. Daily precipitation amounts of ^ 30 mm are possible only in summer. But such days are very unlikely, only 2 days in 10 summer seasons. The highest daily precipitation for the entire observation period in Murmansk (1918-1968) reached 28 mm in June 1954, 39 mm in July 1958 and 39 mm in August 1949 and 1952. Extreme daily rainfall during the summer months occurs during prolonged heavy rains. Thunderstorm rainfalls very rarely give significant daily amounts.

Snow cover can form during snowfall only in early summer, in June. During the rest of the summer, although wet snow is possible, the latter does not form a snow cover.

Of the atmospheric phenomena in summer, only thunderstorm, hail and fog are possible. In early July, a blizzard is still possible, no more than one day in 25 years. Thunderstorms in summer are observed annually, on average about 5 days per season: of which 2 days in June-July and one day in August. The number of thunderstorm days varies considerably from year to year. In some years, in any of the months of summer, a thunderstorm may be absent. The largest number of thunderstorm days ranges from 6 in June and August to 9 in July. Thunderstorms are most likely during the day, from 12 to 18 hours, and least likely at night, from 0 to 6 hours. Thunderstorms are often accompanied by squalls up to 15 m / sec. and more.

In summer, advective and radiation fogs are observed in Murmansk. They are observed at night and in the morning, mainly with northerly winds. The smallest number of foggy days, only 4 days in 10 months, is observed in June. In July and August, as the length of the night increases, the number of foggy days increases: up to two in July and three in August

Due to the low frequency of snowfalls and fogs, as well as haze or haze, the best horizontal visibility is observed in Murmansk in summer. Good visibility ^ 10 km has a repeatability from 97% in June to 96% in July and August. Most likely good visibility in any of the summer months at 13:00, least likely at night and in the morning. The probability of poor visibility in any of the summer months is less than 1%; the visibility in any of the summer months is less than 1% - The largest number of hours of sunshine occurs in June (246) and July (236). In August, due to a decrease in the length of the day and an increase in cloudiness, the average number of sunshine hours decreases to 146. However, due to cloudiness, the actual observed number of sunshine hours does not exceed 34% of the possible

Autumn

The beginning of autumn in Murmansk closely coincides with the beginning of a stable period with an average daily temperature< 10°, который Начинается еще в конце лета, 24 августа. В дальнейшем она быстро понижается и 23 сентября переходит через 5°, а 16 октября через 0°. В сентябре еще возможны жаркие дни с максимальной температурой ^20°. Однако жаркие дни в сентябре ежегодно не наблюдаются, они возможны в этом месяце только в 7% лет - всего два дня за 10 лет. Заморозки начинаются в среднем 19 сентября. Самый ранний заморозок 1 сентября наблюдался в 1956 г. Заморозки и в сентябре ежегодно не наблюдаются. Они возможны в этом месяце в 79% лет; в среднем за месяц приходится два дня с заморозками. Заморозки в сентябре возможны только в ночные и утренние часы. В октябре заморозки наблюдаются практически ежегодно в 98% лет. Самая высокая температура достигает 24° в сентябре и 14° в октябре, а самая низкая -10° в сентябре и -21° в октябре.

In some years, the average monthly temperature can fluctuate significantly even in autumn. So, in September, the average long-term air temperature at a rate of 6.3 ° in 1938 reached 9.9 °, and in 1939 it dropped to 4.0 °. The average long-term temperature in October is 0.2 °. In 1960, it dropped to -3.6 °, and in 1961 it reached 6.2 °.

The largest in absolute value temperature anomalies of opposite signs were observed in September and October in adjacent years. The warmest autumn for the entire observation period in Murmansk was in 1961. Its average temperature exceeded the norm by 3.7 °. October was especially warm this autumn. Its average temperature exceeded the norm by 6 °. Such a warm October for the entire observation period in Murmansk (52 years) and at st. Cola (92 years old) was not yet. In October 1961 there was not a single day with frost. The absence of frosts in October for the entire observation period in Murmansk since 1919 was noted only in 1961. As can be seen from Fig. 29, in the anomalously warm October 1961, anticyclones prevail over the European territory of the USSR, and active cyclonic activity over the Norwegian and Barents Seas

Cyclones from Iceland moved mainly to the northeast through the Norwegian Sea to the Barents Sea, bringing masses of very warm Atlantic air to the northwestern regions of the European territory of the USSR, including the Kola Peninsula. In October 1961, other meteorological elements were anomalous. For example, in October 1961, the frequency of occurrence of the south and south-west wind was 79% at a rate of 63%, and that of the north, north-west and northeast wind was only 12% at a rate of 24%. The average wind speed in October 1961 exceeded the norm by 1 m / sec. In October 1961, there was not a single clear day with a norm of three such days, and the average value of lower cloudiness reached 7.3 points with a norm of 6.4 points.

In the fall of 1961, the fall dates of the transition of the average air temperature through 5 and 0 ° were late. The first was celebrated on October 19 with a delay of 26 days, and the second - on November 6 with a delay of 20 days.

Autumn 1960 can be classified as cold. Its average temperature was 1.4 ° below normal. October was especially cold this autumn. His average temperature was below normal by 3.8 °. There was no such cold October as in 1960 for the entire observation period in Murmansk (52 years). As can be seen from Fig. 30, in cold October 1960 over the Barents Sea, just like October 1961, active cyclonic activity prevailed. But, in contrast to October 1961, cyclones moved from Greenland to the southeast to the Upper Ob and Yenisei, and in their rear very cold Arctic air occasionally penetrated into the Kola Peninsula, causing short-term significant cooling during clearings. In the warm sectors of cyclones, the Kola Peninsula did not receive warm air from the low latitudes of the North Atlantic with abnormally high temperatures, as in 1961, and therefore did not cause significant warming.

The average daily temperature in the fall of 1960 went over 5 ° on September 21, one day earlier than usual, and after 0 ° on October 5, 12 days earlier than usual. In the fall of 1961, a stable snow cover formed 13 days earlier than usual. In October 1960, the wind speed was abnormal (below the norm by 1.5 m / sec.) And cloudiness (7 clear days with a norm of 3 days and only 6 cloudy days with a norm of 12 days).

In autumn, the winter regime of the prevailing wind direction is gradually established. The frequency of the northern wind directions (north, north-west and north-east) decreases from 49% in August to 36% in September and 19% in November, and the frequency of the south and south-west directions increases from 34% in August to 49%) in September and 63% in October.

In autumn, the diurnal periodicity of the wind direction is still preserved. For example, a north wind is most likely in the afternoon (13%), and the least likely in the morning (11%), while a southerly wind is most likely in the morning (42%) and least likely in the afternoon and evening (34%).

An increase in the frequency and intensity of cyclones over the Barents Sea causes a gradual increase in wind speed and the number of days with strong winds of <15 m / s in autumn. Thus, the average wind speed increases from August to October by 1.8 m / s, and the number of days with a wind speed of ^ 15 m / s. from 1.3 in August to 4.9 in October, that is, almost four times. Daily periodic fluctuations in wind speed gradually diminish in autumn. The probability of weak wind decreases in autumn.

In connection with a decrease in temperature in autumn, the absolute moisture content of the surface air layer gradually decreases. The elasticity of water vapor decreases from 10.6 mb in August to 5.5 mb in October. The daily periodicity of water vapor pressure in autumn is as insignificant as in summer, and reaches only 0.2 mb in September and October. The lack of saturation also decreases in the fall from 4.0 mb in August to 1.0 mb in October, and the daily periodic fluctuations of this value gradually fade. For example, the daily amplitude of the lack of saturation decreases from 4.1 mb in August to 1.8 mb in September and to 0.5 mb in October.

Relative humidity in autumn increases from 81% in September to 84% in October, and its daily periodic amplitude decreases from 20% in September to 9% in October.

Daily fluctuations in relative humidity and its average daily value in September also depend on the direction of the wind. In October, its amplitude is so small that it is no longer possible to trace its change from the direction of the wind. There are no dry days with a relative humidity of ^ 30% for any of the observation periods in autumn, and the number of wet days with a relative humidity of 13 hours ^ 80% increases from 11.7 in September to 19.3 in October.

An increase in the frequency of cyclones leads to an increase in the frequency of frontal clouds in autumn (high-stratified As and stratified Ns clouds). At the same time, the cooling of the surface air layers causes an increase in the frequency inversion frequency and associated subinversion clouds (stratocumulus St and stratus Sc clouds). Therefore, the average lower cloudiness during autumn gradually increases from 6.1 points in August to 6.4 in September and October, and the number of cloudy days by lower cloudiness from 9.6 in August to 11.5 in September.

In October, the average number of clear days reaches an annual minimum, and cloudy - an annual maximum.

Due to the predominance of stratocumulus clouds associated with reversals, the highest cloudiness in the autumn months is observed in the morning, 7 hours, and coincides with the lowest surface temperature, and therefore, with the highest probability and intensity of the inversion. In September, the diurnal frequency of occurrence of Cumulus Cu and Stratocumulus Sc clouds is still traced (Table 44).

In autumn, an average of 90 mm of precipitation falls, of which 50 mm in September and 40 mm in October. Precipitation in autumn falls in the form of rain, snow and sleet with rain. The share of liquid precipitation in the form of rain in autumn reaches 66% of their seasonal amount, and solid (snow) and mixed (wet snow with rain) only 16 and 18% of the same amount. Depending on the prevalence of cyclones or anticyclones, the amount of precipitation in the autumn months can differ significantly from the long-term average. So, in September, the monthly amount of precipitation can vary from 160 to 36%, and in October from 198 to 14% of the monthly norm.

Precipitation occurs in autumn more often than in summer. The total number of days with precipitation, including the days when they were observed, but their number was less than 1 mm, reaches 54, i.e., rain or snow is observed in 88% of the days of the season. However, light precipitation prevails in autumn. Precipitation ^ = 5 mm per day is much less common, only 4.6 days per season. Abundant precipitation ^ 10 mm per day falls even less frequently, 1.4 days per season. Precipitation ^ 20 mm in autumn is very unlikely, only one day in 25 years. The highest daily rainfall of 27 mm fell in September 1946 and 23 mm - in October 1963.

For the first time, snow cover forms on October 14, and in cold and early autumn on September 21, but in September the snow that falls does not cover the soil for a long time and always melts. A stable snow cover is formed already in the next season. In an abnormally cold autumn, it can form no earlier than October 5. In autumn, all atmospheric phenomena observed in Murmansk during the year are possible (Table 45)

From the data table. 45 shows that fog and rain, snow and sleet are most often observed in autumn. Other phenomena typical of summer, thunderstorm and hail, stop in October. Atmospheric phenomena characteristic of winter - blizzard, fog of evaporation, ice and frost, which cause the greatest difficulties for various sectors of the national economy, are still unlikely in the fall.

An increase in cloudiness and a decrease in the length of the day leads to a rapid decrease in the duration of sunshine in the fall, both actual and possible, an increase in the number of days without sun

Due to the increase in the frequency of snowfalls and fogs, as well as haze and air pollution by industrial facilities, a gradual deterioration in horizontal visibility is observed in autumn. The frequency of good visibility ^ 10 km decreases from 90% in September to 85% in October. The best visibility in autumn is observed during the daytime, and the worst - at night and morning.

The content of the article

CLIMATE, long-term weather regime in a given area. The weather at any given time is characterized by certain combinations of temperature, humidity, wind direction and speed. In some types of climates, the weather changes significantly every day or according to seasons, in others it remains unchanged. Climate descriptions are based on statistical analysis of average and extreme meteorological characteristics. As a factor in the natural environment, climate affects the geographical distribution of vegetation, soil and water resources, and therefore land use and economics. Climate also has an impact on human living conditions and health.

Climatology is the science of climate that studies the reasons for 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. the weather.

CLIMATE FORMING FACTORS

Position of the Earth.

When the Earth revolves around the Sun, the angle between the polar axis and the perpendicular to the orbital plane remains constant and is 23 ° 30ў. This movement explains the change in the angle of incidence of sunlight 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 ° 30ў N to 23 ° 30ў S) do 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 warming 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 sunlight is relatively small and the days are much shorter. At the equator, day and night always have equal duration, while at the poles, 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 partially compensates for the low standing of the Sun above the horizon, and as a result, the summer is cool here. In dark winters, the polar regions quickly lose heat and become very cold.

Distribution of land and sea.

Water heats up and cools more slowly than dry 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, they speak of a continental climate.

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

Circulation of the atmosphere.

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 high pressure areas to low pressure areas. High pressure is usually associated with cold, dense air, while low pressure is associated with warm and less dense air. The rotation of the Earth causes air currents to deflect 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 intertropical convergence zone at the equator, the northeastern trade wind approaches the southeastern trade wind. Tradewinds originate in high-pressure subtropical regions, most developed over the oceans. Air currents, moving towards the poles and deflected by the Coriolis force, form the predominant westerly transport. In the region of polar fronts of temperate latitudes, the western transport meets the 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, sometimes the polar eastward transport is 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 areas of convergence of air currents form ascending air currents, which cools with height. In this case, the formation of clouds is possible, often accompanied by precipitation. Therefore, a lot of precipitation falls in the intertropical convergence zone and frontal zones in the belt of the prevailing western transport.

Winds blowing in the higher layers of the atmosphere close the circulation system in both hemispheres. The air that rises upward in the convergence zones rushes into the high-pressure area and descends there. At the same time, with increasing pressure, it heats up, which leads to the formation of a dry climate, especially on land. These downdrafts define the climate of the Sahara, located in the subtropical high-pressure belt in North Africa.

Seasonal changes in heating and cooling determine 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. So, for the African savannas, covered with grassy vegetation with sparsely growing trees, rainy summers (due to the influence of the intertropical convergence zone) and dry winters are characteristic, when a high pressure area with downgrading air flows into this territory.

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

Ocean currents

are formed under the influence of near-surface winds and differences in water density due to changes in its salinity and temperature. The direction of currents is influenced by the Coriolis force, the shape of the sea basins and the outlines of the coast. 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.

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 sea surface, fog often occurs in such areas.

The relief of the earth's surface.

Large landforms have a significant impact on the climate, which changes depending on the height of the terrain and in 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 down. This cooling, called adiabatic cooling, often leads to condensation of moisture and the formation of clouds and precipitation. Most of the precipitation due to the barrier effect of mountains falls on their upwind side, while the leeward side remains in the "rain shadow". Air descending on leeward slopes heats up when compressed, forming a warm, dry wind known as a phene.

CLIMATE AND LATITUDE

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

MAIN CLIMATE TYPES

Climate classification provides an ordered system for characterizing climate types, their regionalization and mapping. The types of climate that prevail over large areas are called macroclimates. A macroclimatic region should have more or less homogeneous climatic conditions that distinguish it from other regions, although it is only a generalized characteristic (since there are no two places with an identical climate), more consistent with realities than the allocation of climatic regions only on the basis of belonging to a certain latitudinal -the geographical belt.

Ice sheet climate

dominates in Greenland and Antarctica, where the average monthly temperatures are below 0 ° C. In the dark winter season, these regions do not receive any 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 ice. Both summer and winter, the elevated regions of the Antarctic Ice Sheet are characterized by low temperatures. The climate of the interior of Antarctica is much colder than the climate of the Arctic, since the southern continent is large and high, and the Arctic Ocean softens the climate, despite the widespread distribution of pack ice. In summer, during short warmings, drifting ice sometimes melts.

Precipitation on ice sheets falls in the form of snow or small particles of ice fog. The interior regions receive only 50–125 mm of precipitation annually, but more than 500 mm can fall on the coast. Sometimes cyclones bring clouds and snow to these areas. Snowfalls are often accompanied by strong winds that carry significant amounts of snow, blowing it off the rocks. Strong katabatic winds with blizzards blow from the cold ice sheet, carrying 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 border of this climatic zone runs significantly 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 shortness of summer, but in most of the territory, the heat received is not enough to completely thaw the soil. Permafrost soil, called permafrost, inhibits plant growth and the filtration of melt water into the soil. Therefore, in summer, flat areas turn out to be swampy. On the coast, winter temperatures are slightly higher, and summer temperatures are slightly lower than in the interior regions of the mainland. In summer, when humid air is above cold water or sea ice, fog often occurs on the Arctic coasts.

Annual precipitation usually does not exceed 380 mm. Most of them fall in the form of rain or snow in the summer, during the passage of cyclones. On the coast, most of the precipitation can be brought by winter cyclones. However, the low temperatures and clear weather of the cold season, typical for most areas with a subpolar climate, are unfavorable for significant snow accumulation.

Subarctic climate

It is also known under the name "taiga climate" (according to the prevailing 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 climate zone. Sharp seasonal climatic differences are manifested here due to the position of this climatic zone in rather high latitudes in the inner parts of the continents. Winters are long and extremely cold, and the farther north, 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 at times can exceed + 32 ° С. In Yakutsk, the average temperature in January is –43 ° С, in July - + 19 ° С, i.e. the annual temperature range reaches 62 ° C. A milder climate is typical for coastal areas, such as southern Alaska or northern Scandinavia.

Most of the climatic zone under consideration receives less than 500 mm of precipitation per year, and their amount is maximum on the windward coasts and minimum in the inner part of Siberia. There is very little snowfall in winter, snowfalls are associated with rare cyclones. Summers are usually more humid, and it rains mainly when atmospheric fronts pass. Fogs and overcast clouds are frequent on the coasts. In winter, in severe frosts, ice fogs hang over the snow cover.

Humid continental climate with short summers

characteristic of a vast strip of temperate latitudes of the Northern Hemisphere. In North America, it stretches from the prairies in the south of 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 great as in the subarctic climate. In Moscow, the average temperatures in January are –9 ° С, in July - + 18 ° С. 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 winters are warmer than inland areas, as the easterly winds bring in warmer ocean air at times.

Annual precipitation 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 falls mainly in summer, often during thunderstorm showers. Winter precipitation, mainly in the form of snow, is associated with the passage of fronts in cyclones. Blizzards are often seen in the rear of the cold front.

Humid continental climate with long summers.

Air temperatures and the length of the summer season increase southward in humid continental climates. This type of climate is manifested in the temperate latitudinal belt of North America from the eastern 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. It is also dominated by the western transfer. 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 humid continental climates with short summers, but temperatures sometimes drop below 0 ° C. The annual temperature range is usually 28 ° C, as, for example, in Peoria, Illinois, USA, where the average temperature in January –4 ° С, and in July - + 24 ° С. On the coast, the annual temperature amplitudes decrease.

Most often, in a humid continental climate with long summers, from 500 to 1100 mm of precipitation falls per year. 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 associated fronts.

Temperate maritime climate

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; with intrusions of continental air during the day, the temperature can rise for a short time to + 38 ° C. This type of climate with a small annual temperature amplitude is the most temperate among climates of temperate latitudes. For example, in Paris, the average temperature in January is + 3 ° С, in July - + 18 ° С.

In areas of a temperate maritime climate, the average annual precipitation ranges from 500 to 2500 mm. The most humidified are the windward slopes of the coastal mountains. In many areas, rainfall occurs fairly evenly throughout the year, with the exception of the Pacific Northwest coast of the United States, which has very wet winters. Cyclones moving from the oceans bring a lot of precipitation to the western continental outskirts. In winter, as a rule, the weather is cloudy 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 to the 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 province in South Africa and the east coast of Australia. Summers in the humid subtropics are 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 humid subtropics, the average annual precipitation ranges from 750 to 2000 mm, the distribution of precipitation over the seasons is quite even. In winter, rains and occasional snowfalls are brought mainly by cyclones. In summer, precipitation falls mainly in the form of thunderstorms associated with powerful inflows of warm and humid oceanic air, characteristic of the monsoon circulation of eastern Asia. Hurricanes (or typhoons) occur in late summer and fall, 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 Mediterranean coasts, which is why this climate is also called Mediterranean. The climate is the same in southern California, central Chile, in the extreme south of Africa and in several areas in southern Australia. All these areas have hot summers and mild winters. As in the humid subtropics, there are occasional frosts in winter. Inland temperatures are much higher in summer than on coasts and are often the same as in tropical deserts. In general, clear weather prevails. Fogs are common on the coasts near which ocean currents pass in summer. 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 western air currents are shifted towards the equator. The influence of anticyclones and downdrafts under the oceans are responsible for the dryness of the summer season. The average annual precipitation in a subtropical climate ranges from 380 to 900 mm and reaches its maximum values ​​on the coasts and slopes of the mountains. In 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, macchia and finbosh.

Semi-arid climate of temperate latitudes

(synonym - steppe climate) is typical 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 semiarid climate are the intermontane 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 "semi-arid" is used to characterize this climate because it is less dry than the arid climate itself. The average annual precipitation is usually less than 500 mm, but more than 250 mm. Since the development of steppe vegetation in conditions of higher temperatures requires more precipitation, the latitudinal-geographical and altitude position of the area is determined by climatic changes. For a semiarid climate, there are no general patterns of precipitation distribution throughout the year. For example, in areas bordering the subtropics with dry summers, the maximum precipitation is observed in winter, while in areas adjacent to areas of humid continental climate, it rains mainly in summer. Cyclones in temperate latitudes bring most of the winter precipitation, which often falls as snow and can be accompanied by strong winds. Summer thunderstorms are not uncommon with hail. The amount of precipitation varies greatly from year to year.

Arid climate of temperate latitudes

inherent mainly in the Central Asian deserts, and in the west of the United States - only in small areas in intermontane basins. The temperatures are the same as in regions with a semi-arid climate, however, there is not enough rainfall for the existence of a closed natural vegetation cover, and the average annual amounts usually do not exceed 250 mm. As in semiarid climatic conditions, the amount of precipitation, which determines the aridity, depends on the thermal regime.

Semi-arid climate of low latitudes

mostly typical of the outskirts of tropical deserts (eg, the Sahara and the deserts of central Australia), where downdrafts in subtropical high pressure zones eliminate precipitation. The climate in question differs from the semiarid climate of temperate latitudes in very hot summers and warm winters. Average monthly temperatures are above 0 ° C, although frosts sometimes occur in winter, especially in areas farthest from the equator and located at high altitudes. The amount of precipitation required for the existence of closed 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) outskirts of deserts, the maximum precipitation occurs in winter. Most of the precipitation falls in the form of thunderstorms, and in winter it is brought in by cyclones.

Arid climate of low latitudes.

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

In most of this climatic region, the average annual precipitation does not exceed 125 mm. It so happens that precipitation has not been recorded at all at many meteorological stations for several years in a row. 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, strong thunderstorms, but the water drains quickly, forming flash floods. The driest areas are along the western coasts of South America and Africa, where cold ocean currents inhibit cloud formation and precipitation. Fogs are common on these coasts, formed by condensation of moisture in the air over the colder ocean surface.

Variably humid tropical climate.

Regions with such a climate are located in tropical sublatitudinal zones, several degrees north and south of the equator. This climate is also called monsoon tropical, as it prevails in those parts of South Asia that are influenced by monsoons. Other regions 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 precipitation ranges from 750 to 2000 mm. During the summer rainy season, the intertropical convergence zone has a decisive influence on the climate. Thunderstorms often occur here, sometimes overcast clouds with prolonged rains remain for a long time. Winter is dry, as subtropical anticyclones dominate this season. In some areas, it does not rain 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 in winter, Asian continental dry air masses spread here.

Humid tropical climate

or a tropical rainforest climate, common in equatorial latitudes in the Amazon basins in South America and the Congo in Africa, on the Malacca 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 noon standing of the Sun above the horizon and the same day length throughout the year, seasonal temperature fluctuations are small. Humid air, cloudiness and dense vegetation prevent nighttime cooling and maintain maximum daytime temperatures below + 37 ° C, lower than in higher latitudes.

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 intertropical convergence zone, which is located slightly north of the equator. Seasonal displacements of this zone to the north and south in some areas lead to the formation of two maximum precipitation during the year, separated by drier periods. Thousands of thunderstorms roll over the humid tropics every day. In between, the sun shines in full force.

Highland climates.

In high-mountainous regions, a significant variety of climatic conditions is due to latitudinal-geographical position, orographic barriers and different exposure of 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 snow falls towards the poles, reaching sea level in the polar regions. Similarly, other boundaries of high-altitude thermal belts decrease as they approach high latitudes. The windward slopes of mountain ranges receive more precipitation. On mountain slopes that are open to cold air intrusion, the temperature may drop. 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 pattern 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 - middle) are the climates of territories measuring several square kilometers, for example, wide river valleys, intermountain depressions, depressions of large lakes or cities. In terms of the area of ​​distribution and the nature of the differences, the 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 city streets or on test sites established within a homogeneous plant community.

EXTREME CLIMATE INDICATORS

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

Extreme precipitation values ​​have been recorded in various parts of the world. For example, in the 12 months from August 1860 to July 1861 in the town of Cherrapunji (India), 26 461 mm fell. The average annual rainfall at this point, one of the rainiest on the planet, is approx. 12,000 mm. Less data are available on the amount of snow that fell. At Paradise Ranger Station in Mount Rainier National Park, Washington, USA, 28,500 mm of snow were recorded during the winter of 1971-1972. At many meteorological stations in the tropics with long observation records, precipitation has never been observed 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 layer are likely to develop in tornadoes (tornadoes), where, according to estimates, they can well exceed 800 km / h. In hurricanes or typhoons, the wind sometimes reaches 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 conditions 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 subzero temperatures. With an increase in temperatures, the needs of plants for moisture increase. Light is essential for photosynthesis as well as for flowering and seed development. Shading the soil with tree crowns in dense forest suppresses the growth of lower plants. An important factor is also the wind, which significantly changes the temperature and humidity regime.

The vegetation of each region is an indicator of its climate, since the distribution of plant communities is largely influenced by the 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 southern slopes, where the soil thaws to greater depths in summer. Coniferous forests of spruce, fir, pine and larch, also called taiga, grow in a subarctic climate.

Wet areas of temperate and low latitudes are especially favorable for the growth of forests. The densest forests are confined to areas of a 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, for example, in areas of a subtropical climate with dry summers or a variable-humid tropical climate, plants adapt accordingly, forming either a short or sparse tree layer. So, in savannas in conditions of a variable-humid tropical climate, grasslands with single trees growing at large distances from one another predominate.

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

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

Many animals are able to adapt to a wide range of climatic conditions. For example, mammals in colder climates or in winter have warmer fur. However, they also care about the availability of food and water, which varies with climate and season. Many animal species are characterized by seasonal migrations from one climatic region to another. For example, in winter, when grasses and shrubs dry up in the changing tropical climate of Africa, there are massive migrations of herbivores and predators to more humid areas.

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

Crop distribution and soil cultivation practices are closely related to climatic conditions. Bananas and rubber trees require an abundance of heat and moisture. Date palms grow well only in oases in arid low-latitude areas. Most crops in arid temperate and low latitudes require irrigation. A common type of land use in semiarid climates where grasses 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 damage. In the mountains, agricultural production is differentiated by altitude 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 altitudes in the temperate zone (tierra templada), coffee is the typical crop. Above is the cold belt (tierra fria), where crops and potatoes are grown. In an even colder zone (tierra helada), located just below the snow line, livestock grazing is possible on alpine meadows, and the range of crops is 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, heat conduction, convection and evaporation of moisture from the surface of the body. If these losses are too large in cold weather or too small in hot weather, the person experiences discomfort and may become ill. Low relative humidity and high wind speed enhance the cooling effect. Changes in the weather lead to stress, impair appetite, disrupt biorhythms and reduce the human body's resistance to disease. Climate also affects the habitat of disease-causing pathogens, and therefore seasonal and regional disease outbreaks occur. Pneumonia and influenza epidemics in temperate latitudes often occur in winter. Malaria is widespread in the tropics and subtropics, where there are conditions for the breeding of malaria mosquitoes. Diseases caused by inadequate nutrition are indirectly related to the climate, as the food produced in a particular region, as a result of the influence of climate on plant growth and soil composition, may lack some nutrients.

CLIMATE CHANGE

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

Climatic changes over a historical period can sometimes be reconstructed based on 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 span 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 warming was replaced by relatively stable stages.

Experts in 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. Currently, the Earth is closest to the Sun in January, but about 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 located at the latitude of the modern equator, then, accordingly, the climatic zones also shifted.

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

Air pollution also contributes to climate change. Large masses of dust and gases that entered the atmosphere during volcanic eruptions occasionally became an obstacle to solar radiation and led to cooling of the earth's surface. Increases in the concentration of some gases in the atmosphere exacerbate the overall warming trend.

Greenhouse effect.

Like the glass roof of a greenhouse, many gases allow most of the sun's heat and light energy to pass to the Earth's surface, but prevent the heat radiated by it from quickly escaping into the surrounding space. The main greenhouse gases are water vapor and carbon dioxide, as well as methane, fluorocarbons and nitrogen oxides. Without the greenhouse effect, the earth's surface temperature would drop so much that the entire planet would be covered with ice. However, exaggerating 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 economic activities and especially the combustion of fossil fuels. Many scientists now believe that the rise in global average temperature since 1850 is mainly due to an increase in atmospheric carbon dioxide and other anthropogenic greenhouse gases. If current trends in fossil fuel use continue into the 21st century, the global average temperature could rise by 2.5–8 ° C by 2075. If fossil fuels are used at a faster rate than currently, this temperature increase could occur by 2030.

The projected increase in temperature could lead to the melting of polar ice and most mountain glaciers, causing sea level to rise by 30-120 cm. All this may also affect the changing weather conditions on Earth, with possible consequences such as prolonged droughts in the leading agricultural regions of the world. ...

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

Literature:

Poghosyan Kh.P. General circulation of the atmosphere... L., 1952
Blutgen I. Geography of climates, v. 1–2. M., 1972-1973
Vitvitsky G.N. Zonality of the Earth's climate... M., 1980
Yasamanov N.A. Ancient climates of the Earth... L., 1985
Climate fluctuations over the past millennium... L., 1988
Khromov S.P., Petrosyants M.A. Meteorology and climatology... M., 1994



In winter, the total solar radiation reaches the highest values ​​in the south of the Far East, in southern Transbaikalia and Ciscaucasia. In January, the extreme south of Primorye receives over 200 MJ / m 2, the rest of the listed areas - over 150 MJ / km 2. To the north, the total radiation decreases rapidly due to the lower position of the Sun and a decrease in the length of the day. K 60 ° N it already decreases 3-4 times. North of the Arctic Circle, the polar night is established, the duration of which is 70 ° N. is 53 days. The radiation balance in winter is negative throughout the country.

Under these conditions, there is a strong cooling of the surface and the formation of the Asian Maximum centered over Northern Mongolia, southeastern Altai, Tuva, and the south of the Baikal region. The pressure in the center of the anticyclone exceeds 1040 hPa (mbar). Two spurs extend from the Asian maximum: to the northeast, where the secondary Oymyakon center with a pressure of over 1030 hPa is formed, and to the west, to the connection with the Azores maximum, - the Voeikov axis. It stretches through the Kazakh Upland to Uralsk - Saratov - Kharkov - Chisinau and further up to the southern coast of France. In the western regions of Russia within the Voeikov axis, the pressure drops to 1021 hPa, but remains higher than in the territories located to the north and south of the axis.

The Voeikov axis plays an important role in the climate separation. To the south of it (in Russia it is the south of the East European Plain and the Ciscaucasia), east and north-east winds blow, carrying dry and cold continental air of temperate latitudes from the Asian maximum. South-west and west winds blow to the north of the Voeikov axis. The role of the western transport in the northern part of the East European Plain and in the northwest of Western Siberia is enhanced by the Icelandic minimum, the trough of which reaches the Kara Sea (in the Varangerfjord area, the pressure is 1007.5 hPa). Relatively warm and humid Atlantic air often enters these regions with a westerly transfer.

The rest of Siberia is dominated by winds with a southern component, carrying continental air from the Asian maximum.

Over the territory of the Northeast, in the conditions of a depression relief and minimal solar radiation in winter, continental arctic air is formed, which is very cold and dry. From the northeastern spur of high pressure, it rushes towards the Arctic and Pacific oceans.

The Aleutian minimum is formed near the eastern shores of Kamchatka in winter. On the Commander Islands, in the southeastern part of Kamchatka, in the northern part of the Kuril island arc, the pressure is below 1003 hPa, on a significant part of the Kamchatka coast, the pressure is below 1006 hPa. Here, on the eastern outskirts of Russia, the low pressure area is located in the immediate vicinity of the northeastern spur, therefore, a high pressure gradient is formed (especially near the northern coast of the Sea of ​​Okhotsk); cold continental air of temperate latitudes (in the south) and arctic (in the north) is carried to the water area of ​​the seas. The winds of the northern and northwestern points prevail.

In winter, the Arctic front is established over the water area of ​​the Barents and Kara Seas, and in the Far East - over the Sea of ​​Okhotsk. The polar front at this time passes south of the territory of Russia. Only on the Black Sea coast of the Caucasus is the influence of the cyclones of the Mediterranean branch of the polar front affected, the paths of which shift from Western Asia to the Black Sea due to the lower pressure over its expanses. The distribution of precipitation is associated with the frontal zones.

The distribution of not only moisture, but also heat on the territory of Russia in the cold period is largely associated with circulation processes, which is clearly evidenced by the course of the January isotherms.

The -4 ° C isotherm passes meridionally through the Kaliningrad region. The isotherm of -8 ° С passes near the western borders of the compact territory of Russia. In the south, it deviates to the Tsimlyansk reservoir and further to Astrakhan. The further to the east, the lower the January temperatures. Isotherms -32 ...- 36 ° C form closed circuits over Central Siberia and the North-East. In the basins of the North-East and the eastern part of Central Siberia, average January temperatures drop to -40 ..- 48 ° C. The cold pole of the northern hemisphere is Oymyakon, where the absolute minimum temperature in Russia is recorded, equal to -71 ° С.

The increase in the severity of winter to the east is associated with a decrease in the frequency of occurrence of Atlantic air masses and an increase in their transformation when moving over a cooled land. Where warmer air from the Atlantic (western regions of the country) penetrates much more often, winters are less severe.

In the south of the East European Plain and in the Ciscaucasia, isotherms are located sublatitudinally, rising from -10 ° С to -2 ...- 3 ° С. This is the effect of the radiation factor. Winter is milder than in the rest of the territory on the northwestern coast of the Kola Peninsula, where the average January temperature is -8 ° C and slightly higher. This is due to the flow of air warmed over the warm North Cape current.

In the Far East, the course of isotherms repeats the outlines of the coastline, forming a clearly pronounced concentration of isotherms along the coastline. The warming effect here affects the narrow coastal strip due to the prevailing air outflow from the mainland. The isotherm of -4 ° C stretches along the Kuril ridge. Slightly higher than the temperature on the Commander Islands Along the eastern coast of Kamchatka, the isotherm of -8 ° C stretches. And even in the coastal strip of Primorye, January temperatures are -10 ...- 12 ° С. As you can see, in Vladivostok, the average January temperature is lower than in Murmansk, which lies beyond the Arctic Circle, 25 ° to the north.

The greatest amount of precipitation falls in the southeastern part of Kamchatka and the Kuril Islands. They are brought by cyclones not only of the Okhotsk, but also mainly of the Mongolian and Pacific branches of the polar front, rushing into the Aleutian minimum. Pacific sea air is drawn into the front of these cyclones and carries the bulk of the sediment. But on most of the territory of Russia in winter, Atlantic air masses bring precipitation, therefore, the bulk of precipitation falls in the western regions of the country. To the east and northeast, the amount of precipitation decreases. A lot of precipitation falls on the southwestern slopes of the Greater Caucasus. They are brought by Mediterranean cyclones.

Winter precipitation in Russia falls predominantly in solid form, and snow cover is established almost everywhere, the height of which and the duration of occurrence vary within very wide limits.

The shortest duration of snow cover is typical for the coastal regions of the Western and Eastern Ciscaucasia (less than 40 days). In the south of the European part (up to the latitude of Volgograd), snow lies less than 80 days a year, and in the extreme south of Primorye - less than 100 days. To the north and northeast, the duration of the snow cover increases to 240-260 days, reaching a maximum in Taimyr (over 260 days a year). Only on the Black Sea coast of the Caucasus, a stable snow cover does not form, but during the winter there can be 10-20 days with snow.

Less than 10 cm snow thickness in the deserts of the Caspian region, in the coastal regions of the Eastern and Western Ciscaucasia. In the rest of the territory of the Ciscaucasia, on the East European Plain south of Volgograd, in Transbaikalia and the Kaliningrad region, the height of the snow cover is only 20 cm.In most of the territory, it ranges from 40-50 to 70 cm. In the northeastern (Ural) part of the East European the plains and in the Yenisei part of Western and Central Siberia, the height of the snow cover increases to 80-90 cm, and in the snowiest regions of the southeast of Kamchatka and the Kuriles - up to 2-3 m.

Thus, the presence of a sufficiently thick snow cover and its prolonged occurrence is characteristic of most of the country's territory, which is due to its position in temperate and high latitudes. With the northern position of Russia, the severity of the winter period and the height of the snow cover are of great importance for agriculture.