The duration of sunshine is the total number of hours during a day, month, or year when the Sun in a given area is above and not covered by clouds. It depends on the latitude of the place, the length of the day and the amount of clouds.
In the annual course, the minimum duration of sunshine throughout the entire territory occurs in December, the maximum in July; sometimes it shifts to June, depending on the annual cycle. In the Far East, the maximum is observed in March, since in the summer, due to the large number of cloudy days during the summer monsoon, the duration of sunshine sharply decreases (see table, Cape Lopatka).
To distribute the duration of sunshine over the territory of Russia in the autumn winter period it typically increases from north to south. Largest values observed in the south of Primorsky Krai (up to 200 hours per month). In the spring-summer period, the distribution of sunshine duration over the territory is a rather complex picture, since the influence of latitude is overlapped by the influence of cloudiness. Thus, in April, the maximum duration of sunshine (more than 300 hours) occurs in the north-west of the Republic of Sakha (Yakutia), while at the same latitudes of the European part of Russia, where the influence of the Atlantic is strong and, therefore, cloudiness is increased, the duration sunshine is 180 hours or less.
In July, a decrease in the duration of sunshine is observed along the northern and eastern coasts, also due to increased cloudiness. In the north, this is due to increased cyclonic activity on the polar front, in the east – with the influence of the monsoon. On , and the Kuril Islands it is cloudy and the duration of sunshine is reduced to 120–160 hours. The maximum duration of sunshine in July is observed in northern regions Eastern Siberia and in the south of the European part of Russia (more than 320 hours), which is 50–70% of the possible. At the same time, the duration of sunshine on a day with sun is on average 10–11 hours.
In general, for the year the greatest number of hours of sunshine on the territory of Russia is typical for, Amur region and the south of the Primorsky Territory (more than 2400–2600 hours), the smallest for the northern coastal areas, southern Kamchatka and the Kuril Islands (1200 hours or less).
In conditions mountainous terrain The duration of sunshine decreases sharply, especially in valleys, basins and on sheltered mountain slopes. Only for stations located in open areas is there an increase in the duration of sunshine with latitude. The difference in the duration of sunshine between stations located in mountain valleys and on flat open ground can be 200 hours or more.
SUNSHINE, the time during which direct Sun rays illuminate the earth's surface. At meteorological stations duration C, s. measured by a heliograph. Depends on length. day and cloudiness, expressed in hours or as a percentage of the longest possible duration. To the territory region smallest number hours S.s. per year (1000-1200) is observed on the coast of the Kara Sea, which is explained by the position in high latitudes, heavy clouds and frequent fogs. To the Yu. duration S. s. increases and is in the region of the North. Arctic Circle 1500 hours, on Avg. Priobye - 1700 h, in the south. district - 2020 hours. Some reduction in the duration of S. s. noted in prom. cities due to high air pollution. Naib. number of hours S. s. observed in July between 60° and 69° N. w. - 290-320 hours (45-55% of the possible value), which is due to Ch. arr. increasing day length in years. time at high latitudes. To the south from 60° N. w. number of hours S. s. decreases to 270-290. Shortest duration of S. s. celebrated in December. KS. from North Arctic Circle at this time. polar night is observed, the number of hours increases towards the south: in the south of the Yamal-Nenets Autonomous Okrug -10 hours, in Wed. Priobye - 20 o'clock, in the South region. - 40 hours, in the spring the number of hours S. s. 2-3 times more than in autumn, which is associated with the annual variation of cloudiness, In current. entire year duration of S. s. in the afternoon hours are less than in the afternoon. Lit.: Solar radiation, radiation balance and Sun shine: Handbook on the climate of the USSR. Vol. 17.4.1.-L., 1966. O. V. Soromotina
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Introduction
The duration of sunshine is recorded by a heliograph device, which automatically marks the periods of time during which the sun shone. Currently on the network of meteorological stations USSR The main instrument for recording solar radiation is a heliograph of an ordinary or universal model. Burns on the tape according to the heliograph of the universal model begin when the radiation voltage reaches 0.3 - 0.4 cal/cm.
Typically, a heliograph is installed at a height of 2 m from the surface of the earth in an open place, illuminated by the rays of the sun at any time of the year from sunrise to sunset.
Characteristics of sunshine
The large extent of the territory from north to south (from 62 to 52° N), the presence of almost meridionally directed Ural mountains cause great diversity in the distribution of sunshine. IN total duration Sunshine increases as you move from north to south. In winter, the duration of sunshine decreases faster with increasing latitude than in summer, both due to a decrease in day length and due to an increase in cloudiness with latitude.
The longest duration of sunshine in a year is observed in June, the shortest in December. In some areas, the greatest number of hours of sunshine occurs in July.
Table 4.4. Duration of sunshine.
| I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Year | |
| Kurgan, city | |||||||||||||
| Kurgan-Voronovka |
4.2. Air and soil temperature
4.2.1. Air temperature
Information about air temperature is given based on the readings of liquid thermometers placed in a psychometric booth at a height of 2 m.
The intrinsic temperature of various surfaces located openly, measured simultaneously, differs to varying degrees from the temperature measured in the booth at the same moment.
Table 4.5. Average monthly and annual air temperature.
| I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Year |
| Kurgan, city | ||||||||||||
| -18,5 | -16,7 | -10 | 2,9 | 11,8 | 16,8 | 18,8 | 16,1 | 10,4 | 2,0 | -7,8 | -15,6 | 0,8 |
Table 4.6. Average minimum air temperature.
| I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Year | ||||||||||
| Kurgan, city | ||||||||||||||||||||||
| -23,4 | -22,1 | -15,7 | -2,4 | 4,9 | 9,8 | 12,3 | 10,2 | 5,3 | -1,8 | -11,7 | -20,4 | -4,6 | ||||||||||
4.2.2.Soil temperature
Observation of the thermal state of the soil is carried out from the surface to a depth of 3.2 m.
Average monthly maximum and minimum soil surface temperatures
The temperature of the soil surface is measured by liquid thermometers: mercury (urgent and maximum) and alcohol (minimum).
Table 4.7. Average monthly maximum and minimum soil surface temperatures.
| Soil surface temperature | I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Year |
| Mound | |||||||||||||
| Avg. | -20 | -17 | -10 | -8 | -16 | ||||||||
| Avg. Max | -14 | -10 | -1 | -4 | -11 | ||||||||
| Avg. Min | -26 | -25 | -18 | -5 | -4 | -14 | -23 | -7 |
Table 4.8. Soil freezing depth (cm)
4.3.1. Wind
The wind regime in the temperate latitudes of the USSR is formed under the influence of the main climatic centers of atmospheric action (cyclones and anticyclones) stationary over North Atlantic and over the continent of Eurasia.
Geographical distribution various directions wind and its speed is determined by the seasonal regime of pressure formations. In winter, under the influence of the western spur of the Asian anticyclone, an increase in southern and southwestern winds is observed.
In summer, the wind regime over the territory of the Ural UGMS is associated primarily with the influence of the spur of the Azores anticyclone. The frequency distribution of wind directions during this period is very complex nature. The predominant wind directions are north, northwest and west, but their percentage of the number of winds in all directions is small (15-25% of cases). In summer, there are often two predominant directions, either from the north and northwest, or from the north and west.
In general, throughout the year, winds in the southwestern direction predominate over most of the territory, but due to the complexity of the terrain and the almost meridional (along 60° E) location of the Ural Range, the prevailing direction in certain areas is often southern or western.
Long-term average wind speeds are good comparative characteristics. Despite the complexity and diversity of the relief in the territory, the repeatability of wind speeds, characteristic of these conditions, can be traced in certain physical and geographical conditions. Most of the territory is characterized by weak and moderate winds (from 0 to 5 m/sec). The frequency of wind speeds of 0-5 m/sec is 75-90% of the time, with light winds (0-1 m/sec) accounting for 20-35% of the time, and in valleys located between hills, light winds accounting for 40% of the time. Based on the nature of the frequency curves, groups of stations are distinguished depending on the degree of protection (open, semi-protected and protected), as well as stations whose wind regime is determined by the features of the terrain.
The highest frequency of weak and moderate winds (up to 5 m/sec) occurs in summer months, and wind speeds of 6-10 m/sec - for the cold season or transitional seasons. Wind speeds >10 m/sec are observed relatively rarely, and the frequency for the most part is less than 8%.
Table 4.9. Average monthly and annual wind speed (m/sec).
Table 4.10. Repeatability of wind direction and calms (%).
| Month | WITH | NE | IN | SE | YU | SW | Z | NW | Calm |
| Kurgan, city | |||||||||
| I | |||||||||
| II | |||||||||
| III | |||||||||
| IV | |||||||||
| V | |||||||||
| VI | |||||||||
| VII | |||||||||
| VIII | |||||||||
| IX | |||||||||
| X | |||||||||
| XI | |||||||||
| XII | |||||||||
| Year |
Note: 1. Wind frequency is calculated as a percentage of the number of wind occurrences. 2. The frequency of calms is given as a percentage of total number cases of observations.
4.4. Air humidity, precipitation and snow cover
4.4.1. Air humidity
Air humidity has great importance for many sectors of the national economy: for Agriculture, various industries industry.
Water vapor is unstable integral part atmosphere. Its content varies greatly depending on the physical -geographical conditions terrain, time of year and circulation features of the atmosphere, the state of the soil surface, etc. Air humidity can be judged by the value of water vapor pressure, relative humidity and lack of air saturation with water vapor.
The value of water vapor elasticity characterizes the moisture content of the air and is subject to significant changes due to the large heterogeneity of the territory's topography, changes in the nature and condition of the underlying surface.
The annual variation of water vapor pressure is very similar to the annual variation of air temperature. For this reason, water vapor pressure generally increases from north to south (zonal distribution) almost throughout the year, following the distribution of air temperature. The exception is mountainous areas, where latitudinal zones shift south.
Relative air humidity, which characterizes the degree of saturation of air with water vapor, also has a peculiar distribution. The influence of circulation features, as well as the shape of the relief, the proximity of reservoirs, forests, wetlands, etc. affects the magnitude of the change in relative humidity most clearly. In the annual course, the distribution of relative air humidity is of greatest interest in daytime when relative humidity is close to its minimum and evaporation is most intense. Relative humidity is usually high at night throughout the year.
Table 4.11. Average monthly and annual relative humidity (No.).
| Station | I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Year |
| Kurgan-Voronovka |
The amount of deficiency in air saturation with water vapor is distributed over the course of the year for the same reasons as relative humidity. In accordance with the high relative humidity and low temperatures, the minimum lack of air saturation with water vapor occurs in November - January, when its average value does not exceed 0.5 mb. Maximum values lack of saturation is observed in June. average value in mountainous areas it is 6-7 mb, and on the adjacent plains - 8-10 mb, increasing from north to south. A significant lack of saturation is observed in July and August. From September, with an increase in relative humidity and a decrease in air temperature, the lack of saturation decreases.
Table 4.12. Average monthly and annual saturation deficit (hPa).
| Station | I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Year |
| Kurgan-Voronovka | 0,4 | 0,4 | 0,7 | 3,3 | 8,1 | 8,5 | 6,9 | 4,3 | 2,1 | 0,7 | 0,4 | 3,8 |
4.4.2. Precipitation
The amount and distribution of precipitation throughout the year is determined by the cyclonic activity of the atmosphere and the relief features of the territory under consideration. The meridional orientation of the Ural Mountains causes an increase in precipitation on the western windward slopes and reduces it on the eastern leeward slopes.
According to the degree of moisture, the mountainous part of the territory and the mountain slopes, especially the western, belong to the zone excess moisture. Areas adjacent directly to mountain slopes belong to the zone of sufficient moisture.
Table 4.13. Average precipitation, normalized to precipitation gauge readings (mm).
| Station | I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Year |
| Kurgan-Voronovka |
Annual precipitation amounts consist of solid, mixed and liquid. On average, the share of solid precipitation in the territory under consideration accounts for 20 - 35%, the share of liquid precipitation - 50 - 75%, and the share of mixed precipitation (wet snow, snow with rain, etc.) -10 -15% of the annual amount. The duration of the period with one or another type of precipitation in the territory changes relatively little, because The type of precipitation mainly depends on general climatic factors.
Table 4.14. Solid (t), liquid (l) and mixed (s) sediments as a percentage of the total.
(-) – half a percent or less
The annual course of precipitation throughout the territory has common features, characteristic of a continental climate: the main amount of precipitation falls in the warm season, and the transition from small winter precipitation to significant occurs in most areas quickly, especially in the Trans-Urals.
4.4.3. Snow cover
Winter within the territory under consideration is the longest of all seasons of the year. From the total amount of precipitation falling in a year. 20-35% consists of solid sediments containing the bulk of water reserves. It is snow cover that creates the main source for spring feeding of rivers. Snow cover is one of the the most important factors, influencing climate formation.
All physical and geographical processes in winter, including temperature regime, soil freezing, overwintering conditions for winter crops, moisture accumulation in the soil, etc., depend on both the height and the nature of the snow cover.
The nature of the occurrence of snow cover in strong degree depends on wind speed and open or sheltered conditions of the site.
Table 4.15. Average ten-day snow depth based on the constant rake (cm).
Table continuation.
Table 4.16. Snow cover density according to snow surveys on the last day of the decade (g/cm3).
Table continuation.
4.5. Clouds and atmospheric phenomena
The regime of cloudiness and atmospheric phenomena (fogs, snowstorms, thunderstorms, hail) in the territory under consideration are mainly determined by the peculiarities of atmospheric circulation in individual seasons and the influence of relief.
The territory under consideration is clearly divided into zones with varying degrees hydration. Such diversity natural landscapes with significant heterogeneity of the relief leads to great diversity in the distribution of cloudiness and atmospheric phenomena over the territory.
4.5.1. Cloudiness
The average long-term cloudiness regime is influenced by circulation processes that determine the prevailing direction of air masses and their moisture content, as well as by the influence of underlying surfaces.
Influenced by changes in inflow solar radiation and the nature of the underlying surface, processes change over the seasons, according to which the amount of cloud cover and the shape of the clouds change.
IN autumn months and in the first half of winter, when the cyclonic type of weather is most developed, continuous clouds cover the entire region. In the lower part of the Middle Urals, total cloudiness decreases to 80%. In the foothills and mountainous areas, cloudiness increases noticeably, and in warm times the influence of the height of the place is more pronounced than the shape of the relief. In the Trans-Ural region, a small number of cases of low cloudiness are observed throughout the year (about 7%), and in January and February not a single case with such cloudiness was recorded.
The formation of low clouds in difficult orographic conditions largely depends on the wind direction.
Table 4.17. The number of clear and cloudy days based on total and low cloudiness.
| Number of days | Cloudiness | I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Year |
| Kurgan-Voronovka | ||||||||||||||
| Clear | General | 3,7 | 4,4 | 4,6 | 4,1 | 2,5 | 2,7 | 2,5 | 3,7 | 2,3 | 1,7 | 2,8 | 3,4 | |
| Lower | 13,4 | 16,6 | 15,8 | 13,6 | 11,7 | 9,9 | 9,7 | 11,6 | 9,1 | 8,3 | 9,9 | 11,5 | ||
| Cloudy | General | 10,1 | 8,1 | 10,0 | 9,0 | 9,5 | 7,5 | 9,6 | 8,2 | 11,4 | 15,3 | 13,7 | 13,2 | |
| Lower | 1,4 | 1,4 | 2,1 | 2,1 | 2,4 | 1,2 | 2,4 | 2,4 | 3,7 | 4,5 | 5,0 | 3,9 |
Table 4.18. Frequency of clear (0-2), semi-clear (3-7) and cloudy (8-10) sky conditions based on total and lower cloudiness (%).
| Cloudiness, points (from to) | I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII |
| Kurgan-Voronovka | ||||||||||||
| General | ||||||||||||
| 0-2 | ||||||||||||
| 3-7 | ||||||||||||
| 8-10 | ||||||||||||
| Lower | ||||||||||||
| 0-2 | ||||||||||||
| 3-7 | ||||||||||||
| 8-10 |
4.5.2. Atmospheric phenomena
4.5.2.1. Fogs
The distribution of fogs in the area under consideration is highly variable. This is explained by the great diversity of both the physical and geographical conditions of the territory and the characteristics of atmospheric circulation.
The main reason for the formation of fogs is the cooling of air from the underlying surface due to effective radiation. Thus, as a result of cooling earth's surface by radiation, and also as a consequence continental climate, radiation fog mainly prevails throughout the area.
In conditions large city In winter, a lot of radiation fog is formed. The maximum number of days with fog occurs in January. Op is related to the fact that in cold period at severe frosts industrial smoke and soot play the role of condensation nuclei and, with the additional supply of water vapor, significantly contribute to the formation of fog.
In winter, the duration of fogs is usually longer than in summer.
Table 4.19. Average number of days with fog.
| I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | X-III | IV-IX | Year |
| Kurgan-Voronovka | ||||||||||||||
Table 4.20. Most days with fog.
| I | II | III | IV | V | VI | VII | VIII | IX | X | XI | XII | Period | Year | ||
| X-III | IV-IX | ||||||||||||||
| Kurgan-Voronovka | |||||||||||||||
4.5.2.2. Blizzards
In the territory under consideration, in winter, when cyclonic activity intensifies, snowstorms are a common occurrence. Depending on the physical-geographical and circulation conditions and the general protection of the area, in some areas the frequency and intensity are greater, in others their frequency is less and they are weaker.
The main role in the synoptic processes that cause snowstorms belongs to cyclones. When cyclones pass, the wind increases, causing snowstorms. They can occur during cyclones of various origins, but most often they are associated with the passage of southern and western cyclones, which cause a short-term increase in air temperature, increased wind and strong snowstorms, especially strong development blizzards occur when a cyclone approaches an intensifying anticyclone, when horizontal baric gradients increase significantly and wind speed increases. The formation of large baric gradients ahead of the cyclone usually leads to an expansion of the snowstorm zone, since when the wind increases, drifting snow and blowing snow begin long before the passage of the warm front.
The duration of blizzards, as well as the number of days with a blizzard, is greatest on open slopes, hills and mountain tops.
Drifts of snow are more often observed in the area of the anticyclone. They are usually noted with more low temperatures when the snow is dry. In these cases, a slight increase in wind is enough to create a ground blizzard.
The average number of days with drifting snow varies depending on both the shape of the relief, the state of the snow cover, and the general protection of the area. Most drifting snow occurs in the steppe part of the territory and in open, elevated places (more than 15 days a year).
In winter, under conditions of predominance of the western spur of the Asian anticyclone, an increase in the Trans-Urals is observed in southwestern and western winds, during which snowstorms are most often observed. Very rarely snowstorms occur with northerly winds.
Wind speed during snowstorms is still to a greater extent, than the direction depends on the physical and geographical conditions and the general protection of the area. Blizzards are observed at both low and high wind speeds.
Table 4.21. Average number of days with snowstorms.
4.5.2.3. Thunderstorms
The formation of thunderstorms is associated with the passage of cold fronts, with convention processes and powerful updrafts in the atmosphere.
Thermal intramass thunderstorms are rare. The occurrence of thunderstorms is closely related to orographic conditions.
Most often, thunderstorms occur in the presence of a slow-moving Arctic anticyclone over the Middle Urals region. These thunderstorms form both during the passage of a front and within an air mass.
In the area under consideration, thunderstorms are observed mainly from April to September.
Table 4.23. Average number of days with thunderstorms.
hail
Hail is observed mainly during the warm period. It usually falls out in patches. Rarely, hail falls in stripes several kilometers long and up to 1-1.5 km wide. Hailfall is usually accompanied by rainfall, thunderstorms, and sometimes squally winds. Hail during a thunderstorm most often falls when cold air masses invade and is often large in size.
Hailfall is associated with the passage of areas of low pressure, instability of air masses and local orographic factors. The increase or decrease in the number of hail events is greatly influenced by hills and mountains, as well as large bodies of water, forested areas. Even in flat conditions small hills influence the increase in the number of hail incidents.
Table 4.25. Average number of days with hail.
| IV | V | VI | VII | VIII | IX | X | Year |
| Kurgan-Voronovka | |||||||
| 0,1 | 0,1 | 0,3 | 0,4 | 0,3 | 0,1 | - | 1,3 |
- one of the amazing phenomena of our planet, which can usually be seen in northern latitudes. But sometimes it can be seen even in London or Florida. Moreover northern lights visible even in the very south of the Earth - in Antarctica. This phenomenon also occurs on other planets. solar system: Mars, Jupiter, Venus.
Northern Lights: what is it?
Northern lights ( Polar Lights or aurora) - luminescence (glow) in the upper layers of the atmosphere of planet Earth. These layers have a magnetosphere due to their interaction with charged particles of the solar wind.
Northern lights are thousands of colorful lights lighting up in the sky on dark nights. Lights come in a variety of shapes and colors: blue, yellow, red, green. In a second the dark sky turns bright colors and it becomes visible around for many kilometers as if during the day. The northern lights or polar lights have been surprising and enchanting people for thousands of years, but not everyone treats them with admiration; in the legends of some peoples, which we will discuss below, they were considered a bad sign.
Northern Lights: what is it and how does it happen?
Let's figure out what these northern lights are that surprise and frighten people living near the north and south poles?
Mikhail Lomonosov guessed the riddle of the mysterious lights, deciding that electricity plays a role here. To confirm his theory, the scientist used flasks filled with various gases, passed current. After the experiment, the flasks shone with unique colors.
Simply put, charged particles emitted by our Sun (solar wind) cause the Earth's air to shimmer with multi-colored lights.
The earth is a magnet for particles, which forms magnetic fields due to currents generated during the rotation of the core, which is based on iron. With the help of magnetic attraction, our planet “catches” the passing solar wind and directs it to where the magnetic poles are located. There, solar particles are instantly attracted to them, and from the collision of the solar wind with the atmosphere, energy appears, converted into light, which forms the northern lights.
The excited atoms calm down and begin to emit a light photophone;
If nitrogen (N) collides with solar particles and loses electrons, its molecules turn blue and violet;
If the electron does not disappear anywhere, then red rays appear;
When the solar wind interacts with oxygen (O), the electron does not disappear, but begins to release rays of green and red colors.
Northern Lights: Legends
Since ancient times, the northern lights have been associated with various mysterious and sometimes even mystical events. Some peoples believed that heavenly fire brought happiness; supposedly the gods had holidays at this time. Others believed that the god of fire was very angry and trouble should be expected. Let's listen to what legends of different nations say about the northern lights.
The Norwegians mention a shimmering bridge that sometimes appears in the sky to bring the gods down to earth. Some called the radiance the fires in the hands of the Valkyries, whose armor is polished to a shine and an amazing radiance arises from them. Others said that the lights are the dance of the souls of dead girls.
In the stories of the ancient Finns, the aurora means the Ruža River, burning with fire, which separates the world of the dead and the world of the living.
North American Eskimos believe that you can make the sky sparkle with colorful lights by whistling, and by clapping your hands you can immediately extinguish them.
Alaskan Eskimos say the northern lights bring bad luck. Before going outside, in the old days they took weapons for protection. Many believed that if you watch the lights for a long time, you can go crazy.
There is every reason to believe that it was thanks to the radiance that myths about dragons arose. Many scientists believe that the battle of St. George, who is the patron of all Englishmen, is connected not with a terrible serpent, but with the aurora!
When can you see the Northern Lights
Those who want to know for sure when you can see the northern lights should read this paragraph carefully. It can be seen clearly frosty night, when the moon is not full, preferably away from the city (so that the light of lanterns does not interfere). The aurora appears mainly from October to January and occurs at an altitude of 80 to 1000 kilometers above sea level and lasts from 1 hour to a whole day.
The more aggressive the Sun behaves, the more explosions occur on it, the longer the aurora lasts. The most beautiful flashes can be seen once every 11 years (this is the cyclicity of the Sun).
Northern Lights, photo which is always spectacular, somewhat reminiscent of a sunset (only at night), but can also be embodied in the form of spirals or arcs. The width of the colored ribbon may well exceed 160 km, length - 1500 km.
The color of the aurora itself depends largely on what gas the solar wind interacts with, but also on the altitude where this happened. If atmospheric gases collide at an altitude of more than 150 km, the color of the aurora will be red, from 120 to 150 km – yellow-green, below 120 km – violet-blue. More often than not, the northern lights appear pale green.
Footage received from space confirmed the version that the aurora was from south side the globe almost mirrors this phenomenon from the northern side. It consists of rings with a diameter of 4000 km that surround the poles.
Where can you see the Northern Lights?
It was possible to see the lights in the Middle Ages, when the north magnetic pole was further east, not only in Scandinavia or northern Russia, but even in northern China.
Now you can see the northern lights near magnetic poles of our planet:
at the north pole (it is clearly visible at the Ross Trench);
V ;
in North America (from 20 to 200 times a year);
in the north of the Scandinavian countries, especially on the island of Spitsbergen. Here you can see it no less often than in North America;
in latitudes between London and Paris - 5-10 times a year;
in northern Florida, the northern lights occur four times a year;
c – on the Kola Peninsula;
in Scotland (and in April);
from space (when there is no influence of the lower dense layers of the atmosphere, which significantly distort the spectacle).
You can see the northern lights on other planets of the solar system - on Jupiter, Venus, Mars, and possibly on Saturn.
So far, all the secrets of the flickering lights have not yet been solved. Scientists are especially interested in the question of whether it is accompanied by a sound effect.
The first work on cloudiness was carried out by Acad. Wild in the early 70s XIX century. Since until the 70s cloudiness was recorded in words and not in numbers, the accuracy of such determinations is low. The second work was written by Voeikov, who used a 10-point system to assess cloudiness, but for detailed characteristics There was still little cloudiness observed. In 1895, Schoenrock's work was published, containing graphs of the annual variation of cloudiness, as well as a map of cloudiness distribution by season and per year. Later he gave a map of cloudiness distribution (1900), compiled from more complete materials. In 1925, cloudiness maps compiled by E. S. Rubinstein were published in the Atlas of Industry, and later (1939) in the Great Soviet Atlas of the World. In previous works, cloudiness data were not presented for one period. This is done in last job E. S. Rubinstein, although Conrad had already pointed out the possibility of such a reduction.
Sunlight was studied by Figurovsky (1897) and Vannari (1907-1909). There are no more recent works characterizing the distribution of sunshine and cloudiness in the USSR.
ANNUAL CLOUD CURVE
Four main types of the annual cycle of cloudiness in the USSR can be distinguished.
Type I, Eastern European, with maximum cloudiness in winter, minimum in summer, observed approximately between the 60th and 42nd parallels and from western borders USSR to 70° meridian. East of Sea of Azov maximum cloudiness occurs in December, on the northern coast of the Black Sea (Odessa, Taganrog) and in Turkmenistan - in January; in Crimea - in February. A large amplitude of cloudiness is observed throughout the region.
Type II, East Siberian, is characterized by maximum cloudiness in the summer half of the year and minimum in winter. This type is observed in the East Siberian and Far Eastern regions. Here the best is everywhere clear month- January or February. The time of occurrence of the maximum varies within very wide limits: from May to August. Thus, on the lower reaches of the Amur, the maximum is observed in May; on middle currents, in Blagoveshchensk - in June; on the upper reaches, in Nerchinsk, maximums (little outstanding) are in May and August.
Type III, transitional, with minimum and maximum cloudiness in transition seasons, is typical for the rest of the USSR territory (excluding mountain ranges), i.e. for the Western Siberian region (between 60 and 90 degrees of longitude and from 50 to 67 ° N), the Far North, as well as for Bessarabia and the Black Sea coast of the Caucasus.
Type IV, high mountain, has a minimum of cloudiness in winter and a maximum in May or June. Low cloudiness in the mountains in winter is explained by the fact that at this time of year predominantly low stratus clouds are formed that do not reach the tops of the mountains (Greater and Lesser Caucasus, mountains Central Asia, Altai).
The amplitude of the annual variation of cloudiness, as a rule, increases in the direction from the coasts towards the interior of the continent, while the average cloudiness in the same direction decreases.
The daily variation of cloudiness in the warm half of the year in the European part of the USSR has two maxima: one at night (due to stratus clouds in the corresponding types of weather), the other during the day (with the formation of clouds due to rising currents); in the cold half of the year, only one maximum is usually observed (at night or in the morning). In the Asian part of the USSR, there is predominantly one cloud maximum - in the summer in the daytime, in the winter in the morning.
In the mountainous regions of the country, the daytime maximum cloudiness is clearly expressed in summer, while in winter - at night.
CLOUD DISTRIBUTION
According to Brooks' calculations, the average cloud cover is distributed in the following way depending on latitude (for the northern hemisphere):
In the USSR, the greatest cloudiness is observed over the Arctic and the White Sea (latitude about 70°), where it averages 88% per year, and in November and December 94% (Sosnowiec lighthouse). Towards the south and especially to the southeast, cloudiness decreases, amounting to 35-25% in Turan (latitude 40° - 50°), 50% in the Crimea and Transcaucasia, 35% in Transbaikalia and Central Asia, and 35% in the Far East. 40%.
In winter, the least cloudiness is observed in Transbaikalia and the East Siberian region (20-35%), which is closely related to high atmospheric pressure and low temperatures.
60% of the winter isonef crosses the middle of the Caspian Sea and, touching the western outskirts of the Aral Sea, heads towards the Urals. Then it runs along the eastern slope of the Urals to the mouth of the Ob, and then turns southeast and, skirting the Vasyugan swamps, reaches Novosibirsk. Then the isonefa follows the Yenisei to the Kara coast. Thus, along the eastern slope of the Urals and in the central part of the West Siberian Lowland, cloudiness is somewhat reduced, which should be associated with western descending air masses passing through the Urals.
On the Murmansk coast and the Kola Peninsula, cloudiness decreases to 70%. in some places up to 65%. which is similar to the distribution of relative humidity, which is lower here than on the mainland, because the adjacent bodies of water are warmer than the mainland and heating from the sea affects the coast. To the west of here, cloudiness increases, reaching 80% in the Baltics. Over the territory of the Karelo-Finnish Republic, cloudiness is slightly reduced (70%), which is in close connection with the anticyclone dominating Finland.
Winter isonephs are mainly directed from north to south, since winter is characterized by a decrease in cloudiness from west to east.
In spring, due to weakening atmospheric circulation, cloudiness decreases in the west and increases due to increased convection of warm air in the east.
In summer, cloudiness decreases from north to south (from 70% in the Arctic to 10% in Turan). Over the Baltic coast the cloudiness is low (45-50%), which Schenrock explains by the foehn reaching here from Sweden. Kaminsky denied such an explanation, since if the air masses brought by the hairdryer had reached here, they would have already been moistened as a result of passing over the sea. Research by Kaminsky, Mikhailovskaya and others has established that over the flat coasts of the seas, summer cloudiness is reduced due to poorly developed convective currents; sea winds They experience almost no friction here and do not have time to warm up for convection to form.
The least cloudiness in summer (10% on average for August) is observed in Central Asia. In the North Caucasus, cloudiness is increased due to air masses rising here along the mountain slopes, brought by the prevailing winds from the northern component.
In summer, compared to winter, the distribution of cloudiness is as if rotated by 90°: in winter, cloudiness decreased from west to east, in summer it decreases from north to south (increasing somewhat in the east and decreasing in the west), so that the isonefs now go mainly along the parallels .
Autumn - transition period. The cloudiness distribution is close to its annual distribution. In the north, cloudiness is 70°%, in the south (in Central Asia) 20-30%. On the shore Baltic Sea there is no decrease in cloudiness, which was observed in the summer.
Closely related to cloudiness is the distribution of clear and cloudy days. The number of clear days on average per year in the USSR ranges from 20 in the White Sea region to 200 in the Turano-Kazakh region, cloudy days - from 200 to 20, respectively. The Trans-Caspian regions are distinguished by cloudless weather, where there are up to 200 completely clear days a year (Termez 207 ), and Transbaikalia (Chita 140); Transbaikalia also stands out because there are few cloudy days here in the year (Chita has on average only 38 cloudy days). The cloudiest weather is typical White Sea, where the average annual number of cloudy days is about 200, and clear days - no more than 20. In the annual course, the largest number of clear days is in the European part of the USSR, Western Siberia and Central Asia falls in the summer. In the Far East and Eastern Siberia, the maximum clear days occur in winter.
The greatest probability of cloudy days for the European part of the USSR occurs in winter: in January it reaches 80% here, while in the Asian part it is from 30% to 60%, and in Transbaikalia even 20%; July is the most cloudy Far East And Far North USSR (60-70%); cloudy weather is least likely in the Turano-Kazakh region (5%).
A.F. Dyubuk provides the following data characterizing the frequency (in%) of clear and cloudy days at different air masses in the European part of the USSR.
The greatest number of cloudy days is in winter, especially during TV and MPV. Clear days have a significant repeatability (27%) in AB, while in mPV and TV they are almost absent.
In summer, the greatest number of cloudy days occurs with AB and cPV, and clear days - with mPV and TV.
SUN SHINE
The duration of sunshine per year increases from north to south and from west to east in inverse proportion to cloudiness. Thus, along the 30th meridian the number of hours of sunshine per year is: in Pavlovsk (ph = 59°4G) - 1550, in Busany (ph = 58°ZG) - 1642, in Novy Korolev (ph = 55°09′) -1860, in Korostyshev (ph = 50°19′) - 2044, in Odessa (ph = 46°30′) - 2200.
The increase in the duration of sunshine from west to east can be seen at the following stations located approximately at the 54th parallel: Suwalki (у = 22°57′) - 1800, Minsk (у = 27°33′) -1930, Polibino (у = 52°56'1 - 2200, Troitsk (y=61°34′) - 2300, Bodaibo (y=114°13′) - 2088.
However, there are exceptions to the rule. In the east of the European part of the USSR, in Ufa, Molotov and the North Caucasus, there are areas with short duration of sunshine. These anomalies are due to the intense formation of clouds here.
Above the major ones industrial centers, where the turbidity of the atmosphere is greatest, there is a noticeable decrease in the number of hours of sunshine. In Leningrad, the average daily duration of sunshine is 3.8 hours, i.e. less than in Khalil (4.1) and Pavlovsk.
In the summer half of the year, the Turan Lowland stands out in terms of the number of hours of sunshine: in Bayram Ali there is only 7% less sun than in Cairo. In Central Asia, the duration of sunshine in summer reaches 92% of the possible south coast Crimea 80%, in Tbilisi 70%, in Guduar 54%. On the Baltic Sea coast, the duration of sunshine is longer than in the interior of the mainland. In the winter half of the year, Transbaikalia (about 1000 hours), Kislovodsk (760 hours), Sukhumi (770 hours) have the largest number of hours of sunshine.
The daily duration of sunshine in the warmer months varies in the European part of the USSR from 4.5 hours in the north (Teriberka) to 11.5 hours in the south (Yalta), in the Asian part from 6 hours. in the north (Igarka) until 14:00. in the south (Termez). In the cold half of the year (October-March), the duration of sunshine ranges from 0 to 5 hours. per day.
The annual course of sunshine is generally opposite to the course of cloudiness. All points in the USSR can be divided into two main groups: 1) stations with one annual maximum, 2) stations with two maximums.
In the north of the USSR, the maximum duration of sunshine occurs in June, i.e., during the polar period.
When moving south, the maximum moves towards autumn, so that in Turan the main maximum is already in August or September.
In Siberia, the main maximum of sunshine occurs in spring, the minimum in autumn; In the Far Eastern region, the summer minimum and winter maximum of sunshine duration are sharply expressed, caused here by the cloudiness of the monsoon periods. In the south of the European part of the USSR, one maximum occurs in May, the other in July or August.
Local geographical factors violate the pattern of annual distribution of sunshine duration. For example, in Akatui in summer there is little sun during the daytime hours due to the predominance of cumulus and thunderstorm clouds; similarly in Kislovodsk (from May to July especially) the duration of sunshine is less than in a significant part of European territory
In Siberia, winter is a clear season, and there is more sun at midday than in the rest of the USSR. In the northwestern part of the USSR there is little sun, especially from November to February, which is associated not only with the short length of the day, but also with the passage of many cyclones and the formation of fogs.