Turkish sights. All sights of Turkey (223). Ruins of Ancient Troy

1. Classification of clouds.

2. Microphysics of clouds.

3. Light phenomena in clouds.

4. Electricity of clouds and precipitation.

5. Daily and annual course of cloud cover.

1. Cloud classification

Clouds are one of the most interesting natural phenomena. In that complex complex of elements and phenomena, which is united by the concept of weather, clouds play a decisive role. They change the thermal and radiation regime of the atmosphere and thus have a great influence on many aspects of human activity. First of all - for agriculture, forestry, various types of transport (especially for aviation). Until now, clouds and fogs significantly affect the takeoff, landing and flight of the aircraft. The flight of an aircraft in the clouds is accompanied by:

severe deterioration in visibility;

the occurrence of glaciation;

"chatter" (a consequence of developed turbulence).

Cloud - a visible set of suspended drops of water or ice crystals located at a certain height above the earth's surface.

Cloud - fog in height (V.I. Dal).

From the point of view of the microphysical structure, there is no fundamental difference between clouds and fogs. But they differ significantly in the conditions for the formation of vertical power, water content and other parameters.

Clouds - systems suspended in the atmosphere (not at the very surface of the earth) products of condensation (condensation) of water vapor - drops of water, ice crystals, both of them. They are called cloud elements (Meteorological Dictionary, 1974).

Clouds form as a result of the condensation of water vapor in the atmosphere. They are formed either as a result of a general increase in the moisture content in the atmosphere, or under the influence of a decrease in air temperature. And in real conditions, both of these factors play a role. The decrease in temperature can occur as a result of adiabatic cooling, radiation, and turbulent mixing.

The lifetime of a cloud can vary widely. A cumulus cloud can exist for 10–15 minutes, another for several hours. As long as the cloud exists, a continuous process of cloud formation takes place in it: some elements evaporate, others fall out, and still others reappear.

The variety of cloud forms observed in nature in all possible combinations is the result of complex processes developing in the atmosphere.

From the structure of clouds and the precipitation associated with them, one can judge the state of the atmosphere at the moment and (more importantly) about its future changes. By the way, before the beginning of systematic aerological sounding, clouds were an important element of the so-called indirect aerology, since clouds were used to judge processes in the lower half of the troposphere.

Clouds are classified according to several criteria:

by the phase state of cloud elements;

according to the shape and height of the location;

by origin.

By phase state Cloud cloud elements are divided into classes:

water (drip);

mixed;

ice (crystalline).

Water (drip) clouds are made up of drops only. They can exist both at positive and at negative (down to -10°C and below) temperatures. These are altocumulus, stratus, cumulus.

mixed Clouds are made up of a mixture of supercooled droplets and ice crystals. They can exist, as a rule, at temperatures from -10 to -40°C. They are formed as a result of the appearance of crystals in a water cloud, or as a result of crystals entering a water cloud from outside. Mixed clouds give precipitation. These are highly stratified, nimbostratus, cumulonimbus; at low temperatures sometimes also Altocumulus, Stratocumulus, Stratocumulus.

Ice (crystalline) clouds are composed of ice crystals only. They can only exist at temperatures below -40°C. These are all clouds of the upper tier: cirrus, cirrostratus, cirrocumulus, as well as the tops of cumulonimbus clouds.

Shape and height cloud forms in the troposphere are diverse and changeable. But they can be reduced to a relatively small number of types. The first and most successful classification of clouds was proposed in 1803 by the English pharmacologist Luke Howard. Until now, it is considered unsurpassed. It turned out to be so simple and accurate that it is still used by meteorologists. At the end of the 19th century, an international classification of clouds was adopted. Since the 80s of the 19th century, photographs have been used in compiling the classification of clouds. They are currently combined in the International Cloud Atlas. In the modern version of the international classification, clouds are divided into

Three types: pinnate, stratus, cumulus;

Ten genera (forms) - a combination of three types;

In each form, types, varieties and additional features are distinguished.

Top 10 Cloud Shapes

According to the location height: clouds are conventionally divided into three tiers: upper, middle and lower (Table 8). They also distinguish clouds of vertical development: the base of these clouds lies in the lower tier, and the top lies in the middle or upper tier.

Table 8 - Height of clouds of different tiers depending on latitude, km

Brief description of the various forms of clouds

Upper tier - icy, white, not obscuring the Sun.

Spindrift clouds(Ci) consist of separate pinnate elements in the form of thin white threads or white tufts and elongated ridges. They have a fibrous structure and a silky sheen. Due to strong winds, they have a characteristic shape of elongated, disheveled "mare's tails". They have a significant vertical extent (on the order of hundreds of meters).

Types: filiform, claw-like, tower-shaped, dense, flaky.

Varieties: mixed, radial, spinal, double.

cirrocumulus clouds(SS) - high and fluffy, consisting of separate formations (very small grains, flakes, balls, curls). They resemble ripples on the surface of water or sand. Often they form beautiful regular waves: "the sky in the lambs".

Varieties: wavy, perforated.

Sometimes they give falling streaks.

Cirrostratus clouds(Cs) : ice veil, thin, milky white, transparent. The sun shines through them so brightly that rings (halos) appear around it, and sometimes false suns. The thickness of the layer is from hundreds of meters to a kilometer.

Species: filamentous, foggy.

Varieties: double, wavy.

middle tier

Altocumulus clouds(Aс) at medium heights they look like flakes or ridges of white or gray color. Unlike cirrocumulus clouds, which are higher up, they always have darker edges. These are fairly thin clouds. Altocumulus clouds are characterized by such optical phenomena as iridescence and crowns.

Species: layered, lenticular, turret-shaped, flaky.

Varieties: translucent, with gaps, double, wavy, radial, perforated.

Features: streaks of fall, vymeobrazny character.

Highly layered(As) cover the firmament in whole or in part. Through separate clouds, less dense, the Sun or the Moon can shine through. In this case, they are visible as if through glass, in the form of blurry spots. These are typical mixed clouds. They give light rainfall. The halo is not observed.

The types are not different.

Varieties: translucent, non-translucent, double, wavy, radial.

Features: the lower surface sometimes has a vyme-like appearance; patches of lower clouds are often observed under the As layer.

lower tier

Nimbostratus(Ns): gray cloud cover, often gloomy in appearance, appearing washed out. The layer of clouds is more powerful than that of high-stratus, so the Sun and Moon do not shine through them. These clouds are in the lower and middle, and often in the upper tiers. These are mixed clouds: in the lower part they consist of large drops and snowflakes, and in the upper part they consist of small drops and small snowflakes (like As).

Species and varieties are not distinguished.

Features: fall streaks, cloud wisps.

Stratocumulus(sc) often formed from upper cumulus clouds as they rise and spread outward. When viewed from an airplane, they look like a wavy blanket of ridges and ledges with gaps. Rolls, discs, slabs are white in color but always with darker areas, are longer than Ac (> 5°). These are water (droplet) clouds, so they do not give precipitation.

Species: layered, lenticular, turret-shaped.

Varieties: translucent, with gaps, non-translucent, double, wavy, radial, perforated.

Features: vymeiform, structure of the lower surface.

layered(St) are aqueous or mixed, appearing as a uniform gray layer. At low density, the Sun shines through them, while it has a clear outline. Drizzle can fall from stratus clouds, and in winter - ice needles, fine snow, snow grains. The thickness of the layer is up to several hundred meters.

Species: foggy, broken.

Varieties: non-translucent translucent, wavy.

Clouds of vertical development

Cumulus(cu) dense clouds with sharply defined contours. They develop upwards, forming dense white tops, similar to cauliflower, the bases of the clouds are relatively dark. Vertical power varies widely:

for flat ones - tens and hundreds of meters;

powerful ones - more than 5 km.

These are water clouds (consisting of drops), so they do not give precipitation (with the exception of the tropics, where small rains can fall from powerful cumulus clouds).

Types: flat, medium, powerful, broken.

Varieties: radiating.

Features: hat, fall stripes.

Cumulonimbus(CB) larger and darker, the result of further development of cumulus vertically. The vertical thickness of cumulonimbus clouds can vary from 3 to 15 km. They greatly change the illumination (reduce) as they cover the Sun. These are mixed clouds: in the lower part there are drops, in the middle - drops and crystals, in the upper part - crystals. It is with Cb that showers, thunderstorms, squalls, and tornadoes are associated. Rare in polar latitudes.

Species: bald, hairy.

Peculiarities: fall stripes, tatters, anvil, protrusions, hat, veil, collar, occasionally trunk.

Origin allocate genetic types of clouds:

Intramass

a) convection clouds, b) clouds of stable masses.

Frontal

a) upward sliding clouds, b) orographic clouds.

In the first genetic type (intramass), they distinguish convection clouds and clouds of stable air masses.

clouds of convection arise as a result of air cooling in vertical ascending currents. In the first stage of development of thermal convection, when it is only a kind of turbulent motion, these are flat cumulus clouds, as well as fractocumulus; when well-formed ascending currents of significant speed (3.6 m/s or more) arise, powerful cumulus and cumulonimbus clouds appear. In the middle tier, some varieties of altocumulus clouds are associated with convection: tower-shaped and flaky.

Cumulus, or convective, clouds look like isolated cloud masses. They are strongly developed vertically and have a small (medium) extent horizontally.

As a result of uneven heating of the earth's surface by the Sun, "bubbles" of warm air are formed in some places, which rise up and fall into layers of colder air (thermals). There they cool down, the water vapor in them condenses, and clouds form (Figure 30). These bubbles, or convection cells, live no more than 20 minutes, with rare exceptions. Often several cells form in one place, then the cloud can last for about an hour.

According to studies by photogrammetry from the ground and during observations in flights, a convective cloud consists of separate flows that have the form of a jet or thermal (bubble). On average, the diameter of the jets at the earth's surface (and up to a height of about 3000 meters) is 60 meters, and the average concentration of streams is 40 jets per 1 km 2. The sizes of convective flows in powerful cumulus clouds are much larger than outside them (in the cloud d ~ 90 m, under it - 50 m).

Figure 30 - Scheme of the occurrence of thermal convection (Clouds, 2007)

In connection with the development of a convective cloud in the troposphere, the following levels are distinguished:

a) the level of condensation, practically coincides with the lower boundary of the cloud; Zk

b) the level of the zero isotherm separating the supercooled (upper) part of the cloud from the non-supercooled one; Zo

c) the level of free convection, which practically coincides with the upper boundary of the cloud.

Layers with temperature inversions delay convection and prevent further development of cumulus tops.

Dynamic convection is caused by the forced rise of warm air when flowing around an obstacle. The role of an obstacle can be performed by a mountain range (Figure 31) or a frontal surface with a steep angle of inclination.

Convection clouds develop in unstable air masses (in cold high altitudes moving over a warm surface; local high altitudes over land in summer) are called cumulus (not cumulus).

Clouds of persistent air masses arise in connection with the cooling of air from the underlying surface, dynamic turbulence and wave motions in the atmosphere. This cloud subtype includes stratus, stratocumulus, and altocumulus. They have a pronounced wavy structure, therefore they are called wavy.

Figure 31 - Scheme of the occurrence of dynamic convection when the air flows over the ridge (Oblaka, 2007)

In the atmosphere, wave motions of very different amplitudes and wavelengths are observed. Under the influence of such movements, under certain conditions, wavy clouds can form, which have the form of a horizontally distributed (tens and hundreds of kilometers) layer consisting of disks, plates, shafts (Figure 32). These clouds have, on average, a small vertical thickness (several tens or hundreds of meters), but in some cases up to 2–3 km.

Figure 32 - Scheme of the formation of wavy clouds under the inversion layer

(Clouds, 2007)

According to modern data, wavy clouds are formed as a result of the transfer of clouds of other forms from areas of low pressure to areas of increased pressure and their further transformation. Under the existing clouds, an inversion layer is formed as a result of downward air movements. In addition to free waves, forced standing waves can occur in the atmosphere over mountains through which air flows. In this case, clouds of obstacles are formed.

frontal clouds . In connection with the fronts, huge cloud systems arise, stretched along the front line for thousands of kilometers and a width of hundreds of kilometers. Such clouds are called upslip clouds. The front separates a gentle wedge of cold air from a layer of warm air lying next to it and above it. Warm air slowly rises along the cold wedge, which leads to adiabatic cooling of thick layers and condensation of water vapor (Figure 33). The result is a powerful cloud layer. Such clouds are called layered. The largest thickness (several kilometers) are nimbostratus clouds. Farther from the front line, they are replaced by highly stratified, pinnately stratified. At a distance of many hundreds of kilometers from the front line, ridges of cirrus clouds are observed. Frontal clouds can intensify as the front approaches a mountain range.

Figure 33 - Scheme of the formation of clouds of upward sliding (Clouds, 2007)

In addition, there are:

Volcanic eruption clouds are cumulus-shaped clouds that form over volcanoes during eruption. They are characterized by rapid development, abundant clubs. They consist of dust (ash) and water droplets, sometimes they give precipitation. Electrical phenomena may be associated with them.

Damping clouds (deceleration of horizontal air transfer when moving it to the underlying surface with increased friction, especially in front of mountain ranges and massifs).

Clouds of fires - are formed due to the formation of strong upward convection currents over large (forest) fires. Contain products of combustion (smoke, soot, ash). They often look gloomy.

Most often, we don’t really think about what sometimes complex and unusual shapes are for all those clouds that float daily in the sky above our heads. You have probably seen many of the clouds that we have prepared for you right now. But do you know what scientists call them, or what exactly determines their appearance? Each variety has its own peculiarity, and you are unlikely to ever see some clouds from this list with your own eyes ...

25. Storm Collar

These cumulonimbus clouds usually herald a severe thunderstorm or a cold atmospheric front. They form low in the sky and are shaped like a long shaft or roll.

24. Shelf bulk clouds


Photo: pixabay

This type of storm collar also forms in the lower atmosphere during thunderstorms and cold fronts. Protruding roll clouds differ from their counterparts from the previous paragraph in that they are usually associated with a huge parent cloud from above.

23. Kelvin-Helmholtz cirrus clouds


Photo: GRAHAMUK

These thin horizontal spirals dissipate very quickly - almost immediately after their formation, which makes their observation extremely difficult. Resembling sea waves, these clouds are usually associated with the so-called Kelvin-Helmholtz instability, and they form between layers of air with different densities and speeds.

22. Vymeobrazny cloud


Photo: max pixel

These unusual marsupial-shaped clouds form only after a thunderstorm. Contrary to popular belief, they do not portend a tornado or a hurricane, although the false clouds look really intimidating.

21. Pearlescent clouds


Photo: publicdomainpictures.net

In the West, they are also called the "mother of pearl". These clouds occur at altitudes up to 32 kilometers, and they can only be seen in polar latitudes near the poles. A distinctive feature of mother-of-pearl clouds, you guessed it, is their amazing color.

20. Lenticular cloud-hat


Photo: James St. John / flickr

A cap cloud or scarf cloud usually floats very high in the atmosphere on top of larger cumulonimbus clouds.

19. Radiant clouds


Photo: wikimedia commons

They are difficult to see with the naked eye from Earth, so these clouds are best seen from space. In this satellite photo, you can see that the radiant clouds resemble a giant leaf or wheel, and this makes them stand out from the rest of the clouds very much.

18. Wavy clouds


Photo: David E. McIlroy

These clouds are usually formed by air currents that pass over high places. Most often they occur precisely above the mountain ranges.

17. Pyrocumulative clouds


Photo: Jeremy Greene

Sometimes they are also called fiery clouds. Pyrocumulative clouds appear during fires and during volcanic activity.

16. Mysterious clouds of Undulatus Asperatus


Photo: Agathman

Nine years after their discovery, these strange clouds have finally been recognized as a separate species. This happened quite recently - in 2017, and the decision was made by the International Cloud Atlas of the World Meteorological Organization. This event was the first of its kind since 1951. The uniqueness of Undulatus Asperatus clouds is that they are characterized by wave movements and upwards. A new kind of cloud usually forms in the lower atmosphere, and it looks pretty creepy.

15. Cumulus Arcus

Thunder collars and shelf clouds may be classified under the same general type of roll cloud, but there are several other less famous types that deserve their own name. For example, Cumulus Arcus.

14. "Hairy" cumulonimbus clouds Cumulonimbus Capillatus

This subspecies of "umbrellas" is represented by high vertical clouds with a feathery top of a fibrous structure.

13. Cirrus Spissatus Cirrus


Photo: Kr-val

In front of you are the highest cirrus clouds, and they are usually formed from thin crystalline ice plates.

12. Condensation trail


Photo: pixabay

This, of course, is not a natural formation, because in the sky such traces remain precisely from aircraft. This species is technically cirrus, but it belongs to the group of artificial or man-made clouds and is called cirrus aviaticus.

11. Morning glory


Photo: Mick Petrof

This rare phenomenon is very difficult to observe due to its unpredictability. Relatively often, morning glory appears only in the north of Australia.

10. Another kind of wavy clouds


Photo: wikimedia commons

These clouds usually fly parallel to each other, but sometimes they can intertwine with each other. It all depends on the currents of the wind.

9. Cirrostratus Nebulosus Cirrostratus


Photo: Eduardo Marquetti

These clouds are formed by updrafts of air and are difficult to see unless they are illuminated by enough sunlight from the right angle. Cirrostratus Nebulosus usually form a so-called halo - a luminous ring around the sun.

8. Cirrus uncinus cirrus clouds


Photo: Fir0002

From Latin, this name translates approximately as "wavy hooks." They are easily recognizable by their diffuseness in the sky and very thin outlines.

7. Anvil Cumulonimbus (Cumulonimbus Incus)


Photo: TheAustinMan

The upper part of these clouds is flat and shaped like an anvil. Such a cloud easily transforms into a supercell (a kind of thundercloud), which portends severe weather, including even hurricanes and tornadoes.

6. Cloud "Punched hole"


Photo: H. Raab (User: Vesta)

In the West, they are also called "hole-piercing" clouds. Such unusual round gaps appear in the sky when the temperature of the water vapor in the clouds drops below zero, but the water has not yet had time to freeze to the state of ice. Very often this phenomenon is mistakenly associated with UFOs.

5. Indoor clouds


Photo: pixabay

It sounds like something unrealistic, but in fact, it is quite possible to create a cloud indoors. For the occurrence of indoor clouds, there are even several techniques for creating ideal conditions at once. Most often they are used for artistic compositions.

4. Lenticular clouds


Photo: Omnisource5

These almost unchanging clouds in the form of giant lenses or hats usually appear when a stream of moist air flies over the top of a mountain range.

3. Cloud "Nuclear Mushroom"

Photo: pixabay

Such clouds are most often associated with nuclear weapons, although almost any large explosion is capable of triggering something like this. For example, a volcanic eruption or a meteorite fall.

2. Cloud Jellyfish (Altocumulus Castelanus)


Photo: NOAA ESRL / wikimedia commons

These clouds got their unusual name because of their original shape, and they form when moist air gets stuck between layers of drier air currents.

1. Noctilucent clouds


Photo: Gofororbit

This is probably one of the most mysterious types of clouds, and at the same time the highest in the entire atmosphere. Silvery clouds appear at an altitude of about 80 kilometers, that is, almost at the very edge of the earth's atmosphere, where it is already very close to open space. This phenomenon can be observed in the region of the Earth's poles, but for this a number of conditions must coincide. For example, the Sun must be below the horizon, but there must still be enough light to hit the clouds at just the right angle.

This article lists and describes all types of clouds.

Cloud types

Upper clouds are formed in temperate latitudes above 5 km, in polar latitudes above 3 km, in tropical latitudes above 6 km. The temperature at this altitude is quite low, so they consist mainly of ice crystals. Upper clouds are usually thin and white. The most common form of upper clouds are cirrus (cirrus) and cirrostratus (cirrostratus), which can usually be observed in good weather.

Middle clouds usually located at an altitude of 2-7 km in temperate latitudes, 2-4 km in polar and 2-8 km in tropical latitudes. They consist mainly of small particles of water, but at low temperatures they can also contain ice crystals. The most common types of mid-tier clouds are altocumulus (altocumulus), altostratus (altostratus). They may have shaded portions, which distinguishes them from cirrocumulus clouds. This type of cloud usually results from air convection and also from the gradual rise of air ahead of a cold front.

Lower clouds located at altitudes below 2 km, where the temperature is quite high, so they consist mainly of water droplets. Only in the cold season. When the surface temperature is low, they contain particles of ice (hail) or snow. The most common types of low clouds are nimbostratus (nimbostratus) and stratocumulus (stratocumulus), dark low clouds accompanied by moderate precipitation.

Fig1. The main types of clouds: Cirrus, Ci), Cirrocumulus (Cirrocumulus, Cc), Cirrostratus, Cs, Altocumulus (Altocumulus, Ac), Altostratus, As, Altostratus translucidus , As trans) , Strato-nimbus (Nimbostratus, Ns), Stratus (Stratus, St) , Stratocumulus (Stratocumulus, Sc), Cumulus (Cumulus, Cu), Cumulonimbus (Cumulonimbus, Cb)

Pinnate (Cirrus, Ci)

They consist of separate pinnate elements in the form of thin white threads or white (or mostly white) tufts and elongated ridges. They have a fibrous structure and / or a silky sheen. They are observed in the upper troposphere, in the middle latitudes their bases most often lie at altitudes of 6-8 km, in the tropical from 6 to 18 km, in the polar from 3 to 8 km). Visibility within the cloud is 150-500 m. They are built from ice crystals large enough to have an appreciable falling speed; therefore, they have a significant vertical extent (from hundreds of meters to several kilometers). However, wind shear and differences in crystal size cause the filaments of cirrus clouds to be slanted and warped. These clouds are characteristic of the leading edge of a cloud system of a warm front or an occlusion front associated with an upward slip. They often also develop in anticyclonic conditions, sometimes they are parts or remnants of ice tops (anvils) of cumulonimbus clouds.

There are different types: filiform(Cirrus fibratus, Ci fibr.), claw-like(Cirrus uncinus, Ci unc.), turret-shaped(Cirrus castellanus, Ci cast.), dense(Cirrus spissatus, Ci spiss.), flaky(Cirrus floccus, Ci fl.) and varieties: mixed up(Cirrus intortus, Ci int.), radial(Cirrus radiatus, Cirad.), spinal(Cirrus vertebratus, Ci vert.), double(Cirrus duplicatus, Ci dupl.).

Sometimes this genus of clouds, along with the described clouds, also includes cirrostratus And cirrocumulus clouds.

Cirrocumulus (Cirrocumulus, Cc)

They are often referred to as "lambs". Very high small globular clouds, elongated in a line. Look like the backs of mackerels or ripples on the coastal sand. The height of the lower border is 6-8 km, the vertical length is up to 1 km, the visibility inside is 5509-10000 m. They are a sign of an increase in temperature. Often observed together with cirrus or cirrostratus clouds. They are often the forerunners of storms. With these clouds, the so-called. "iridization" - iridescent coloring of the edge of the clouds.

Cirrostratus, Cs

Halo formed on cirrus clouds

Sail-like clouds of the upper tier, consisting of ice crystals. They have the appearance of a homogeneous, whitish veil. The height of the lower edge is 6-8 km, the vertical extent varies from several hundred meters to several kilometers (2-6 or more), visibility inside the cloud is 50-200 m. Cirrostratus clouds are relatively transparent, so the sun or moon can be clearly visible through them. These upper tier clouds usually form when large layers of air rise up through multilevel convergence.

Cirrostratus clouds are characterized by the fact that they often give the phenomena of a halo around the sun or moon. Halos are the result of the refraction of light by the ice crystals that make up the cloud. Cirrostratus clouds, however, tend to thicken as a warm front approaches, which means more ice crystal formation. As a result, the halo gradually disappears, and the sun (or moon) becomes less visible.

Altocumulus (Altocumulus, Ac)

Formation of altocumulus clouds.

Altocumulus (Altocumulus, Ac) - typical warm season cloud cover. Gray, white, or bluish clouds in the form of waves and ridges, consisting of flakes and plates separated by gaps. The height of the lower boundary is 2-6 km, the vertical length is up to several hundred meters, the visibility inside the cloud is 50-80 m. They are usually located above the places facing the sun. Sometimes they reach the stage of powerful cumulus clouds. Altocumulus clouds usually form when warm air masses rise, as well as when a cold front advances, which pushes warm air upwards. Therefore, the presence of altocumulus clouds on a warm and humid summer morning portends the imminent appearance of thunderclouds or a change in the weather.

High-stratified (Altostratus, As)

Altostratus clouds

They look like a uniform or weakly expressed wavy veil of gray or bluish color, the sun and moon usually shine through, but weakly. The height of the lower boundary is 3-5 km, the vertical extent is 1-4 km, the visibility in the clouds is 25-40 m. These clouds consist of ice crystals, supercooled water drops and snowflakes. Altostratus clouds can bring heavy rain or snow.

High-layered translucent (Altostratus translucidus, As trans)

Altostratus clouds at sunset

Altostratus translucent clouds. The wavy structure of the cloud is noticeable, the solar circle of the sun is quite distinguishable. Quite distinguishable shadows can sometimes appear on the ground. Stripes are clearly visible. A veil of clouds, as a rule, gradually covers the entire sky. The height of the base is within 3-5 km, the thickness of the As trans cloud layer is on average about 1 km, occasionally up to 2 km. Precipitation falls, but in low and middle latitudes it rarely reaches the ground in summer.

Nimbostratus (Nimbostratus, Ns)

Nimbostratus clouds and strong air currents.

Nimbostratus clouds are dark gray, in the form of a continuous layer. During precipitation, it seems to be homogeneous; in the intervals between precipitation, some heterogeneity and even some undulation of the layer are noticeable. They differ from stratus clouds in their darker and bluish color, inhomogeneity of the structure and the presence of extensive precipitation. The height of the lower boundary is 0.1-1 km, the thickness is up to several kilometers.

Layered (Stratus, St)

Layered clouds.

Layered clouds form a homogeneous layer, similar to fog, but located at a height of hundreds or even tens of meters. Usually they cover the entire sky, but sometimes they can be observed in the form of broken cloud masses. The lower edge of these clouds can drop very low; sometimes they merge with ground fog. Their thickness is small - tens and hundreds of meters.

Stratocumulus (Stratocumulus, Sc)

Gray clouds, consisting of large ridges, waves, plates, separated by gaps or merging into a continuous gray wavy cover. Composed primarily of water droplets. The thickness of the layer is from 200 to 800 m. The sun and moon can only shine through the thin edges of the clouds. Precipitation usually does not fall. From stratocumulus clouds that are not translucent, weak, short-term precipitation may fall.

Cumulus clouds (Cumulus, Cu)

Cumulus clouds. View from above.

Cumulus clouds are dense, bright white clouds during the day with significant vertical development (up to 5 km or more). The upper parts of cumulus clouds look like domes or towers with rounded outlines. Cumulus clouds usually form as convection clouds in cold air masses.

Cumulonimbus (Cumulonimbus, Cb)

Cumulonimbus (Cumulonimbus capillatus incus)

Cumulonimbus - powerful and dense clouds with a strong vertical development (up to a height of 14 km), giving heavy rainfall with powerful hail and thunderstorms. Cumulonimbus clouds/clouds develop from powerful cumulus clouds. They can form a line called a squall line. The lower levels of cumulonimbus clouds are mostly water droplets, while the higher levels, where temperatures are well below 0°C, are dominated by ice crystals.

The question "What is a cloud?" people wondered back in those distant times, when only birds and the clouds themselves flew across the sky. Wikipedia did not yet exist then, and no one had yet invented or published the Children's Encyclopedia. Therefore, some dreamers just didn’t come up with to explain this phenomenon of nature.

Because clouds look so soft and fluffy from below, there was a time when people thought they were made of fluff.

There were also more amusing assumptions about what these heavenly formations are made of. It was even said that the building material of the white giants floating across the sky is cotton candy.

Of course, these are inventions. What the cloud consists of, scientists learned at the end of the 18th century. It happened when mankind found a way to rise into the sky. It was then that it was possible to answer the question: what does the cloud consist of? It turned out that the clouds that seem white and dense from below are actually ordinary fog. So walking in foggy weather is like traveling through a cloud.
In those same years, people learned what clouds are made of. After all, before that, their nature was also explained in different ways. But all this will be discussed a little later.

In general, clouds can consist not only of water droplets, like ordinary fog, but also of ice crystals. It all depends on how high they are.

Most often, clouds appear at an altitude of 6 to 20 km from the surface of our planet. This part of the atmosphere is called the troposphere. It is here that clouds are formed, consisting of water droplets. The temperature inside such formations is usually above -10 0 C. The clouds that form at this height can have a different structure and shape.

There are also clouds that are born much higher. For example, the so-called mother-of-pearl clouds are born 20-25 km from the Earth. However, the champions are almost invisible noctilucent clouds without special equipment. Their cradle is located at an altitude of 70 to 80 km above sea level.

Why and how do clouds appear?

But how are clouds formed? For children, this is a very important issue. To answer it, you need to get acquainted with another interesting physical phenomenon - condensation. What is it?

We have all seen more than once how steam comes out of the spout of a boiling kettle. If you substitute a cold saucer under this stream, then droplets of water will appear on its surface. This phenomenon is called condensation.

Approximately the same processes take place in the upper layers of the atmosphere. Water vapor, rising higher and higher, cools and begins to condense into liquid droplets, from which clouds form. The size of these droplets is incredibly small - 100, and sometimes 1000 times less than 1 mm. If the steam manages to rise very high, then it will turn not into a liquid, but into a solid state. Therefore, in the uppermost layers of the atmosphere, clouds consist of tiny pieces of ice.

But in order for the steam to begin to condense, only lowering the temperature is not enough. The center of each droplet or crystal is the smallest speck of dust, around which moisture has collected.

By the way, it is for this reason that very large clouds can often be observed over cities where there are a lot of cars or large factories. Indeed, in such places there are much more different air polluting particles in the atmosphere than in sparsely populated areas of our planet.

Why do clouds fly?

From the surface of the Earth, clouds seem so light and airy. In fact, they can weigh many tons. How can a whole cloud of water, consisting of a huge accumulation of water droplets, stay in the air? Everything is very simple. The size of each droplet is so small that even a small stream of air rising from the Earth stops them from falling.

Scientists have calculated that the updraft speed to hold the cloud could be as low as 50 cm per second. If we translate this number into a more understandable form, we get a very small value - 1.8 km / h. And this is much less than the speed of a pedestrian.

What are clouds?

Beautiful white mountains floating in a bright blue sky are always a delight to the eye. But why do they seem like this?
It turns out that the more sunlight passes through the clouds, the whiter they appear to us from Earth. A gray overcast sky only means that the cloud layer is very dense and the sun's rays practically do not pass through it. But black clouds most often just contain a lot of dust. Cloud formations of this color often appear again over industrial areas, where air pollution is most severe.

But clouds differ not only in color, but also in shape. The common name for clouds usually describes their appearance. Although scientists have come up with a very complex classification of clouds, only three types of clouds can be clearly distinguished.

It is this type of accumulation of water vapor in the sky that we most often call clouds. These are the very dazzling white giants, smoothly changing their shape. It is for them that people like to watch, imagining who they look like. Such cloudiness does not bother at all. And this is not surprising, because cumulus clouds are the companions of good weather.

Stratus clouds are not so beautiful anymore. Most often they are gray in a variety of shades. Such clouds are quite dense and consist exclusively of droplets ready to fall to the Earth. They swim not so high above the surface. In this case, the height of the clouds above the ground is about 1-2 km.

If the sky is covered with stratus clouds interspersed with cumulus clouds, then it's okay - the weather is unlikely to deteriorate. This type of cloudiness is often also called stratocumulus clouds. By the way, it is this kind of clouds that appears before the mind's eye when you need to answer the question: "What is cloudiness?". But a solid gray blanket always suggests a long and tedious rain.

And this kind of clouds is located quite high. They can be observed at about seven kilometers altitude. They look like lambs or strokes of oil paint smeared in the sky.

Such cloudiness indicates an imminent change in the weather, not for the better. By the way, cirrus clouds are the most photogenic. The photos in which they are present look incredibly impressive.

The clouds are very heavy. On average, their weight is about 10 tons. In addition, they also have huge sizes. A single cloud can extend over 10 km, and thunderclouds can extend the same distance in height.

The duration of the "life" of clouds depends on the humidity of the air. With normal humidity, a cloud can exist for a very long time. But at low temperatures, the droplets of water that make up the cloud will begin to evaporate quickly and it can live no more than 15 minutes.

It is hard to imagine, looking at the clouds floating across the sky, that this miracle of nature can be created at home. Although in fact a real cloud can be made artificially. True, this requires special equipment. I came up with how to make clouds by the Dutch artist Berndnaut Smilde. His homemade clouds do not last long, about 10 seconds. But during this time they can be photographed or filmed at the moment of the birth of a small cloud.

Such a phenomenon as cloudiness is observed not only on Earth, but also on several other planets in the solar system. Clouds have been detected in the atmosphere of Venus and Mars, as well as on the satellites of Saturn - Titan and Neptune - Triton.

In 2004, several meteorologists and physicists united as part of the international organization "Society of Cloud Lovers". They not only admire these bizarre creatures of the earth's atmosphere themselves, but also urge everyone to raise their eyes to the sky to admire the beautiful and diverse clouds.

Surprisingly, even scientists do not know everything about clouds. Their study is still ongoing. Both in Russia and in the USA, programs are still working to find out all the properties of these beautiful, snow-white, airy islands.