What is above the clouds. What are clouds formed from and what types are they divided into?
Clouds are usually observed in the troposphere. Tropospheric clouds are divided into types, varieties and additional characteristics in accordance with the international classification of clouds. Other types of clouds are occasionally observed: nacreous clouds (at an altitude of 20-25 km) and noctilucent clouds (at an altitude of 70-80 km).
Pinnate (Cirrus, Ci)
They consist of individual feather-like 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, sometimes at tropopause altitudes or directly below it (in middle latitudes their bases most often lie at altitudes of 6-8 km, in tropical latitudes from 6 to 18 km, in polar latitudes from 3 to 8 km). Visibility inside the cloud is 150-500 m. Constructed from ice crystals large enough to have a noticeable fall 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 become skewed and twisted. Halo cirrus clouds usually do not produce well-defined phenomena due to their dissection and smallness of individual cloud formations. These clouds are characteristic of the leading edge of a cloud system of a warm front or an occlusion front associated with upslip. They often also develop in anticyclonic conditions and are sometimes parts or remnants of ice caps (anvils) of cumulonimbus clouds.
There are different types: filamentous (Cirrus fibratus, Ci fibr.), claw-shaped (Cirrus uncinus, Ci unc.), tower-shaped (Cirrus castellanus, Ci cast.), dense (Cirrus spissatus, Ci spiss.), flocculus (Cirrus floccus, Ci fl .) and varieties: entangled (Cirrus intortus, Ci int.), radial (Cirrus radiatus, Ci rad.), ridge-shaped (Cirrus vertebratus, Ci vert.), double (Cirrus duplicatus, Ci dupl.).
Sometimes this type of cloud, along with the described clouds, also includes cirrostratus and cirrocumulus clouds.
Cirrocumulus (Cc)
They are often called "lamb". Very high small spherical clouds, elongated in lines. They look like the backs of mackerels or ripples on the coastal sand. The height of the lower boundary is 6-8 km, the vertical length is up to 1 km, visibility inside is 200-500 m. They are a sign of an increase in temperature. Often observed together with cirrus or cirrostratus clouds. They are often the precursors of a storm. With these clouds, the so-called “iridization” is the rainbow coloring of the edges of the clouds. There is no shading on them, even on the side that is turned away from the sun. They are formed when wave and upward movements occur in the upper troposphere and consist of ice crystals. Cirrocumulus clouds may exhibit haloes and crowns around the sun and moon. Precipitation does not fall from them.
Cirrostratus, Cs)
Sail-like clouds of the upper tier, consisting of ice crystals. They look like a homogeneous, whitish veil. The height of the lower edge is 6-8 km, the vertical extent ranges 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-level clouds usually form when large layers of air rise upward due to multi-level convergence.
Cirrostratus clouds are characterized by the fact that they often produce halo phenomena 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 when a warm front approaches, which means increased ice crystal formation. As a result, the halo gradually disappears and the sun (or moon) becomes less visible.
Altocumulus, Ac
Altocumulus (Ac) - typical cloudiness for the warm season. 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, visibility inside the cloud is 50-80 m. They are usually located above places facing the sun. Sometimes they reach the stage of powerful cumulus clouds. Altocumulus clouds usually occur as a result of rising warm air masses, as well as the arrival of a cold front that pushes warm air upward. Therefore, the presence of altocumulus clouds on a warm and humid summer morning foreshadows the imminent appearance of thunderclouds or a change in weather.
High-stratified (Altostratus, As)
They look like a uniform or faintly 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, vertical length is 1-4 km, visibility in clouds is 25-40 m. These clouds consist of ice crystals, supercooled water droplets and snowflakes. Altostratus clouds may bring heavy rain or snow.
High-layered translucent (Altostratus translucidus, As trans)
Altostratus translucent clouds. The wavy structure of the cloud is noticeable, the solar circle of the sun is quite visible. Quite visible shadows can sometimes appear on the ground. The 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 in summer it rarely reaches the ground.
Layered (Stratus, St)
Stratus clouds form a homogeneous layer, similar to fog, but located at a certain height (most often from 100 to 400 m, sometimes 30-90 m). They usually cover the entire sky, but can sometimes appear as broken cloud masses. The base of these clouds can drop very low; sometimes they merge with ground fog. Their thickness is small - tens and hundreds of meters. Sometimes precipitation falls from these clouds, most often in the form of snow grains or drizzle.
Stratocumulus (Stratocumulus, Sc)
Gray clouds consisting of large ridges, waves, plates, separated by gaps or merging into a continuous gray wavy cover. They consist mainly of water droplets. The height of the lower boundary is usually in the range from 500 to 1800 m. The thickness of the layer is from 200 to 800 m. The sun and moon can only be seen through the thin edges of the clouds. Precipitation, as a rule, does not fall. Light, short-lived precipitation may fall from non-translucent stratocumulus clouds.
Cumulus clouds (Cumulus, Cu)
Cumulus clouds are dense, bright white clouds during the day with significant vertical development. The height of the lower boundary is usually from 800 to 1500 m, sometimes 2-3 km or more. Thickness is 1-2 km, sometimes 3-5 km. The upper parts of cumulus clouds look like domes or towers with rounded outlines. Typically, cumulus clouds occur as convection clouds in cold or neutral air masses.
Nimbostratus (Nimbostratus, Ns)
Nimbostratus clouds are dark gray, in the form of a continuous layer. During precipitation, it appears homogeneous; in the intervals between precipitation, some heterogeneity and even some undulation of the layer is noticeable. They differ from stratus clouds in their darker and bluish color, heterogeneity of structure and the presence of overlying sediments. The height of the lower boundary is from 100 to 1900 m, the thickness is up to several kilometers.
Cumulonimbus (Cb)
Cumulonimbus - powerful and dense clouds with strong vertical development (several kilometers, sometimes up to a height of 12-14 km), producing heavy rainfall with powerful hail and thunderstorm phenomena. Cumulonimbus clouds develop from powerful cumulus clouds. They can form a line called a squall line. The lower levels of cumulonimbus clouds are composed primarily of water droplets, while at higher levels, where temperatures are well below 0 °C, ice crystals predominate. The height of the lower boundary is usually below 2000 m, that is, in the lower tier of the troposphere.
Scientists, naturalists and dreamers love to study clouds and just watch them. When you see one or another celestial phenomenon, there is a desire to call it “big, heavy or rainy,” but it would be much more interesting (and more useful) to use scientific terminology for a more specific description.
For the first time, the English scientist Luke Howard began to classify air halos (nimbus - cloud in Latin), and the main criteria he used were the height of the tier, the shape and, in fact, the weather that created them.
The types of clouds are very diverse and are an interesting “collectible” and just for observation. Knowledge of celestial changes can be a great topic of conversation at a social dinner or a simple party.
Among other things, all the nuances regarding weather changes are extremely necessary for people involved in extreme sports such as boating or rock climbing. Types of clouds, their reading and analysis will help you avoid serious danger and learn about changes in climate conditions without additional metrological tools.
- The height of the nimbus will tell you about an approaching storm.
- Form is about the stability of the atmosphere.
- Together, these factors will warn of critical changes in the weather (hail, snow or rain).
Despite the enormous variety and types of clouds, it is not so difficult to classify them, even by appearance.
Cirrus clouds
In appearance, they resemble fragile threads or scraps. The shape of cirrus clouds is similar to elongated ridges. It is one of the highest air connections in the troposphere, ranging from approximately 5 to 20 km above sea level depending on latitude.
Cirrus anomalies are notable for the fact that they can stretch for several hundred kilometers. Visibility inside the cloud is very low and ranges from 200-300 meters. This is due to the fact that the nimbus consists of large ice crystals that fall quickly.
Due to the gusty wind, we see not clear vertical stripes, but filaments of cirrus clouds curved in a bizarre way.
Such changes indicate an approaching heavy rain or anticyclone in about a day.
Cirrocumulus clouds
Just like the previous type, cirrocumulus anomalies are located in the upper layers of the troposphere. They never produce precipitation, but it can be clearly said that these types of clouds are harbingers of thunderstorms and heavy downpours, and sometimes even storms.
These nimbuses are often called “lamb” for their bizarre shape in the form of groups of balls and circles. The height of the base of the clouds is slightly lower than simple cirrus and ranges from 5-9 km with a vertical extent of about a kilometer. Visibility, unlike the previous view, is much better - from 5 to 10 kilometers.
An interesting feature of cirrocumulus species is iridescence, when the edges are painted in a rainbow color, which looks very impressive and beautiful.
Cirrostratus clouds
This type of nimbus consists almost entirely of ice crystals and is quite easy to recognize. It looks like a homogeneous film covering the sky. It appears after the above-described types of clouds have “gone away”. In winter, their length can vary up to 6 km, and in summer - from 2 to 4 km.
Visibility inside the anomaly itself is extremely low: from about 30 to 150 meters. As with previous types, cirrostratus flows promise a quick change in weather in the form of rain and thunderstorm fronts.
What types of clouds precede rain? All cirrus nimbuses always move ahead of warm air masses, where there is very high humidity, which is the source of rain and downpours. Therefore, we can say that all feathery compounds are harbingers of bad weather.
Even though the anomalies absorb sunlight and moonlight, very colorful phenomena (halos) can sometimes occur and rare types of clouds appear in the form of glowing and iridescent rings around the light of the moon or sun.
Altostratus clouds
In appearance, they resemble a gloomy gray veil, through which sunlight only occasionally peeks through. High-layered compounds are located at an altitude of no more than 5 km above sea level and have a vertical length of up to 4 km.
Visibility in such a cloud is very low - 20-30 meters. They consist of ice crystals and supercooled water. These anomalies may receive a little rain or snow, but in the summer the rain simply does not reach the ground, so we mistakenly consider them not rainy.
Altocumulus clouds
These conjunctions could be the start of rapid rain showers. In their shape, they resemble small balls that gather in separate groups. The color range is very diverse: from white to dark blue. Very often you can see bizarre shapes: a cloud in the shape of a heart, an animal, a flower and other interesting things.
The extent of altocumulus clouds is small and rarely reaches a kilometer. Visibility, as in layered compounds, is low - 50-70 meters. They are located in the middle layers of the stratosphere and are 4-5 km away from the earth. In addition to rain fronts, they may bring with them colder temperatures.
Nimbostratus clouds
These are types of thunderclouds that are dark gray in color and have a very “gloomy” character. They represent a continuous cloudy veil, with no end or edge in sight, with constant rain. This can continue for a very long time.
They are much darker than all other layered compounds and are located in the lower part of the stratosphere, so they hover almost above the ground (100-300 meters). Their thickness reaches several kilometers and the entire process of the passage of the front is accompanied by a cold wind and low temperature.
Cumulonimbus clouds
These are the most powerful nimbuses that nature gave us. They can reach 14 km in width. The appearance of a cumulonimbus cloud is a thunderstorm, rain, hail and gusty wind. It is these anomalies that are called “clouds”.
Sometimes they can line up in a whole series of squall fronts. The composition of cumulonimbus compounds varies and depends on altitude. The bottom layer consists mainly of water droplets, and the top layer consists of ice crystals. This type of halos develops from their nimbostratus counterparts and their appearance cannot bode well.
The types of precipitation falling from clouds can be very diverse: showers, snow, cereals, ice and needles, so it is better to wait out the bad weather under a roof or in any other shelter.
Fog
Fog also applies to low-lying compounds. It's thick and wet, and when you pass through the foggy cloud, you can feel its heaviness. Fog may appear in areas of large water accumulation with low winds.
Very often it appears on the surface of lakes and rivers, but if the wind rises, the fog very quickly dissipates without a trace.
Page 2 of 4
This article discusses the different types and shapes of clouds.
The first criterion by which clouds are divided when answering the question: What types of clouds are there? - this is the height of the location.
Depending on height the locations are as follows types of clouds:
- Upper clouds (Ci, Cs, Cc)– types of clouds located at an altitude of more than 6000 meters from the surface of the earth. They can be observed from a distance of 100-200 km; they usually appear on the side from which the cyclone is coming;
- Mid-level clouds (As, Ac)– types of clouds that occur at altitudes from 2000 to 6000 meters. They differ from the clouds of the previous type by the larger size of the cloud elements, gray color and casting a shadow on the surface of the earth - due to their greater density, they poorly transmit sunlight or moonlight;
- Low clouds (Cu, Sc, St)– types of clouds located at an altitude of less than 2000 meters. Sometimes they lag behind the clouds of the upper tier by 400-500 km, and from the middle tier - by 200-300. They are distinguished by a dark, rich color and cast a thick shadow due to complete opacity. They float low in the form of huge ridges or a continuous veil. Precipitation falls from the lower clouds.
- Clouds of vertical development (Ns, Cb). The lower part of this type of cloud (white, gray or dark gray) can be below 2000 meters, and the top (always white) reaches a level of 6-8 thousand meters. In appearance, they appear as dense cloud masses with flat bases.
Answer to the question: What types of clouds are there? is not limited to listing the types of clouds by height. In turn, the listed types of clouds come in different shapes.
So, according to the shape of the clouds there are....
Cloud shapes. What types of clouds are there?
What are the different shapes of upper level clouds?
cirrus clouds,
Cirrocumulus clouds,
Cirrostratus clouds.
Cirrus clouds (Cirrus, Ci
Color:
white.
Description and shape of the cloud.
These clouds come in a delicate white color in the form of threads, feathers, and wavy ribbons. Slightly silvery tint. They have a fairly large vertical extent - up to several kilometers. However, due to the action of the wind, they are strongly curved. Cirrus clouds are characterized by a rare but very beautiful phenomenon called a “fire rainbow”.
Visibility inside the cloud
: 150-500 meters.
Composition and education
. Consist of ice crystals. They form ahead of a cloud mass of a warm front or an occlusion front. They are also characteristic of anticyclonic conditions, and sometimes remain from the ice tops (anvils) of cumulonimbus clouds.
Cirrus clouds never produce precipitation.
Cirrocumulus (Cc) is a type of upper level cloud.
Color:
white.
Description and shape of the cloud
.
There are lambs, lambs, lambs in the sky... This is exactly them. These clouds are small in size, oval, lined up, and they float high, high above the ground. Reminiscent of ripples in the sand. They do not cast shadows, harbingers of rising temperatures. In cirrocumulus clouds, a halo effect and crowns around the sun and moon can occur.
Visibility inside the cloud
: 200-500 meters.
Composition and education
. The source of material for the formation of cirrocumulus clouds is wave and upward air currents. Cloud element – ice crystals.
Weather prediction from clouds.
For good weather. Most often they dissipate and reveal a blue sky.
Deformed cirrocumulus clouds.
Sometimes round shaped breaks can be observed in cirrocumulus clouds. Such a gap forms when the temperature in the cloud is below zero, but the water has not yet had time to freeze. When water in one place begins to freeze, nearby water vapor quickly evaporates and condenses on ice crystals. Ice crystals become heavy and can settle to the ground under their own weight. This is how deformed cirrocumulus clouds are created.
Cirrostratus clouds (Cirrostratus, Cs) are a type of upper-level cloud.
Color:
whitish, translucent.
Description and shape of the cloud
.
Cirrostratus clouds appear as a continuous veil high in the sky. In the presence of these clouds, the sun and moon float as if in a haze. The transparency of clouds can vary depending on the density of the cloud. At low densities, a halo effect is also observed. The thickness of cirrostratus clouds can reach 2-6 kilometers.
Visibility inside the cloud
: 50-200 meters.
Composition and education.
The source of material for the formation of cirrostratus clouds is entire layers of air rising upward as a result of multi-level convergence. Cloud element – ice crystals.
Weather prediction from clouds.
They do not produce precipitation, but thickening cirrostratus clouds can be a harbinger of bad weather.
What are the different shapes of middle-tier clouds?
altocumulus clouds,
altostratus clouds,
Altostratus translucent clouds.
Altocumulus (Altocumulus, Ac
Color
: white, gray or bluish white.
Description and shape of the cloud
. Altocumulus clouds usually occur in the summer. They are located in waves or in ridges in the form of flakes or plates. There are gaps between individual elements. Sometimes there is a beautiful phenomenon around these clouds called "iridization"
. This is the rainbow coloring of the edge of the cloud.
Visibility inside the cloud
: 50-80 meters.
Composition and education.
Formed when warm air masses rise upward. The rise can be triggered by the onset of a cold front, which displaces air heated at the surface of the earth upward.
Weather prediction from clouds.
Appear after a thunderstorm or storm. They foretell clear weather.
Altostratus clouds (Altostratus, As) are a type of middle-tier cloud.
Color
: gray or bluish.
Description and shape of the cloud
. Altostratus clouds appear in the form of a uniform or slightly wavy veil, through which the sun and moon faintly shine through. The height of the cloud varies from one to four kilometers.
Visibility inside the cloud
: 25-40 meters.
Composition and education.
The main cloud elements are ice crystals, snowflakes, and supercooled water.
Weather prediction from clouds.
Precipitation falls from altostratus clouds. This is continuous rain or snow.
Altostratus translucent clouds (Altostratus translucidus, As trans) - a type of middle-tier cloud
.
Color
: white-bluish.
Description and shape of the cloud
. Clearly visible translucent wavy stripes. The solar and lunar disks are quite distinguishable. Despite this, they cast a faint shadow on the ground. The lower boundary of these clouds is at an altitude of 3-5 km. The height of the cloud mass is 1-2 km. Gradually the entire sky is covered with a continuous veil.
Weather prediction from clouds.
Precipitation also falls from altostratus translucent clouds, but in summer they rarely reach the earth's surface.
What are the different shapes of lower level clouds?
Stratus clouds,
Stratocumulus clouds,
Cumulus clouds.
Stratus clouds (Stratus, St) are a type of lower tier cloud.
Color
: dark gray or light gray.
Description and shape of the cloud
. Stratus clouds appear in the form of a uniform whitish veil that covers the entire sky and looks like fog. The height of the cloud is small - from several tens to hundreds of meters. The lower part can fall very low, and then the cloud merges with fog. Formed in the lower tier of the troposphere.
: 100-400 meters, sometimes drops to 30-90.
Weather prediction from clouds.
Precipitation sometimes falls from stratus clouds. This is drizzle or snow grains, depending on the season.
Stratocumulus (Stratocumulus, Sc) - a type of lower cloud.
Color
: grey.
Description and shape of the cloud
. Stratocumulus clouds come in the form of massive ridges, waves, and plates. They can either have gaps or cover the sky with a continuous wavy veil. The height of the cloud layer is from 200 to 800 meters. Quite dense, the sun shines through only along the edges of the clouds.
Height above ground level
: from 500 to 1800 meters.
Compound
. The main cloud element is water drops.
Weather prediction from clouds.
Precipitation is possible only occasionally, and even then short-lived.
Stratocumulus clouds.
Color
: grey.
Description and shape of the cloud
. A type of stratocumulus cloud. They are notable for the fact that they are located in the sky in the form of regular rows or waves, separated by gaps.
Height above ground level
: from 500 to 1800 meters.
Compound
. Cloud element - water drops.
Weather prediction from clouds.
Most often they foretell good weather.
Cumulus clouds (Cumulus, Cu) - type of lower clouds.
Color
: bright white.
Description and shape of the cloud
. Dense, elongated clouds. The upper part of cumulus clouds is round or in the form of round towers.
Height above ground level
: from 800 to 1500 meters, occasionally more than two kilometers.
Weather prediction from clouds.
If they are located scattered, far from each other, then the weather is good. But if the cumulus clouds are large and multi-story, then there may be heavy rain.
What are the different shapes of vertical development clouds:
nimbostratus clouds,
Cumulonimbus clouds.
Nimbostratus clouds (Nimbostratus, Ns) - a type of cloud with vertical development.
Color
: dark gray, with a bluish tint.
Description and shape of the cloud
. Clouds cover the earth with a continuous veil. Nimbostratus clouds have a heterogeneous structure, sometimes wavy. The layer thickness is up to several kilometers. They differ from stratus clouds by their heterogeneous structure, which becomes blurred during rain or snow. But in the intervals between precipitation, the heterogeneity becomes visible again.
Height above ground level
: from 100 to 1900 meters.
Weather prediction from clouds.
Prolonged precipitation occurs.
Cumulonimbus (Cb) - type of clouds of vertical development
.
Color
: thick dark grey.
Description and shape of the cloud
. Powerful dense clouds reaching a height of more than 10 km. The clouds are preceded by a squally wind, a hurricane. They are distinguished by a flat top - an “anvil”, consisting of ice crystals.
Height above ground level
: up to 2000 meters.
Compound
. At the base there are water drops, and at the top, where the temperature is much lower, there are ice crystals.
Weather prediction from clouds.
Cumulonimbus clouds are a harbinger of bad weather. They bring heavy rain, thunderstorms, and possible hail.
This completes the listing of the main types and the shape of clouds, but there are other, rarer types. They cannot be classified into any of the categories described above, so they are considered separately. In the next article we will answer the question: What other clouds are there?
It was an article “Types and forms of clouds. What types of clouds are there? Read further: Rare types of clouds. What other clouds are there?
1. Classification of clouds.
2. Microphysics of clouds.
3. Light phenomena in clouds.
4. Electricity of clouds and precipitation.
5. Daily and annual variation of cloudiness.
1. Cloud classification
Clouds are one of the most interesting natural phenomena. In that complex complex of elements and phenomena that is united by the concept of weather, clouds play a decisive role. They change the thermal and radiation regime of the atmosphere and thereby have a great influence on many aspects of human activity. First of all, for agricultural production, forestry, and various types of transport (especially aviation). Until now, clouds and fog significantly affect the takeoff, landing and flight of an aircraft. An airplane flying in the clouds is accompanied by:
severe decrease in visibility;
the occurrence of glaciation;
“bumpy” (a consequence of developed turbulence).
Cloud - a visible collection of suspended drops of water or ice crystals located at some height above the earth's surface.
Cloud – fog at altitude (V.I. Dal).
From the point of view of microphysical structure, there is no fundamental difference between clouds and fogs. But they differ significantly in the conditions for the formation of vertical thickness, water content and other parameters.
Clouds – a system of products of condensation (condensation) of water vapor suspended in the atmosphere (not near the earth’s surface) – water droplets, ice crystals, both together. They are called cloud elements (Meteorological Dictionary, 1974).
Clouds arise from the condensation of water vapor in the atmosphere. They are formed either as a result of a general increase in moisture content in the atmosphere, or under the influence of a decrease in air temperature. But in real conditions, both of these factors play a role. Temperature reduction can occur as a result of adiabatic cooling, radiation, and turbulent mixing.
The duration of a cloud's existence can vary widely. A cumulus cloud can last for 10–15 minutes, while another can last for several hours. While the cloud exists, there is a continuous process of cloud formation in it: some elements evaporate, others fall out, and others appear anew.
The variety of cloud shapes observed in nature in all possible combinations is the result of complex processes developing in the atmosphere.
By the structure of clouds and associated precipitation, one can judge the state of the atmosphere at the moment and (more importantly) its nearest changes. By the way, before the start 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;
by shape and height of location;
by origin.
By phase state cloud elements clouds are divided into classes:
water (drip);
mixed;
icy (crystalline).
Mermen (drip) clouds consist only of drops. They can exist at both positive and negative (down to -10°C and below) temperatures. These are altocumulus, stratocumulus, and cumulus.
Mixed clouds consist 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 the outside. Mixed clouds produce precipitation. These are altostratus, nimbostratus, cumulonimbus; at low temperatures sometimes also altocumulus, stratocumulus, stratocumulus.
Icy (crystalline) clouds consist only of ice crystals. They can only exist at temperatures below -40°C. These are all upper level clouds: cirrus, cirrostratus, cirrocumulus, and the tops of cumulonimbus clouds.
By shape and height of location The shapes of clouds in the troposphere are varied and variable. 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 meteorologists still use it today. At the end of the 19th century, an international classification of clouds was adopted. Since the 1980s, photographs have been used to classify clouds. They are currently combined in the International Cloud Atlas. In the modern version of the international classification, clouds are divided into
Three types: cirrus, stratus, cumulus;
Ten genera (forms) - a combination of three types;
In each form, types, varieties and additional features are distinguished.
Top 10 Cloud Shapes
Cirrus (Ci) |
Upper tier |
Cirrocumulus (Cc) |
|
Cirrostratus (Cs) |
|
Altostratified (As) |
Middle tier |
Altocumulus (Ac) |
|
Stratocumulus (Sc) |
Lower tier |
Layered (St) |
|
Nimbostratus (Ns) |
|
Cumulus (Cu) |
Vertical development |
Cumulonimbus (Cb) |
According to the height of their location: clouds are conventionally divided into three tiers: upper, middle and lower (Table 8). Clouds of vertical development are also distinguished: the base of these clouds lies in the lower tier, and the top is in the middle or upper tier.
Table 8 – Height of clouds of different tiers depending on latitude, km
Brief characteristics of different cloud shapes
Upper tier – icy, white, not obscuring the Sun.
Cirrus clouds(Ci) consist of individual pinnate elements in the form of thin white threads or white tufts and elongated ridges. They have a fibrous structure and a silky shine. Due to strong winds, they have the characteristic shape of elongated, disheveled “mare’s tails.” They have a significant vertical extent (on the order of hundreds of meters).
Types: thread-like, claw-shaped, tower-shaped, dense, flocculent.
Varieties: entangled, radial, ridge-shaped, double.
Cirrocumulus clouds(Ss) – tall and fluffy, consisting of individual formations (very small grains, flakes, balls, curls). They resemble ripples on the surface of water or sand. They often form beautiful regular waves: “the sky is filled with lambs.”
Varieties: wavy, holey.
Sometimes they give falling streaks.
Cirrostratus clouds(Cs) : ice veil, thin, milky white, transparent. The sun shines through them so brightly that rings (halos) and sometimes false suns appear around it. The thickness of the layer ranges from hundreds of meters to a kilometer.
Types: thread-like, foggy.
Varieties: double, wavy.
Middle tier
Altocumulus clouds(Ac) at medium altitudes look like flakes or rollers of white or gray color. Unlike cirrocumulus clouds, which are higher, they always have darker edges. These are quite thin clouds. Altocumulus clouds are characterized by optical phenomena such as iridescence and crowns.
Types: layered, lenticular, tower-shaped, flocculent.
Varieties: translucent, with gaps, double, wavy, radial, perforated.
Features: fall stripes, snake-like character.
High-layered(As) cover the sky entirely or partially. The Sun or Moon can shine through individual clouds, which are less dense. In this case, they are visible as if through glass, in the form of blurry spots. These are typical mixed clouds. They give light precipitation. No halo is observed.
The species do not differ.
Varieties: translucent, non-translucent, double, wavy, radial.
Features: the lower surface sometimes has a serpentine appearance; Patches of lower clouds are often observed beneath the As layer.
Lower tier
Nimbostratus(Ns): Gray cloud cover, often gloomy in appearance, appearing washed out. The layer of clouds is thicker than that of altostratus clouds, so the Sun and Moon do not shine through them. These clouds are found 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 patches.
Stratocumulus(Sc) often form from upper cumulus clouds as they rise and spread outward. If you look at them from an airplane, they look like a wavy blanket of rollers and protrusions with gaps. Rollers, disks, slabs are white but always with darker areas, have a greater extent than Ac (> 5°). These are water (drip) clouds, so they do not produce precipitation.
Types: layered, lenticular, tower-shaped.
Varieties: translucent, with gaps, non-transparent, double, wavy, radial, perforated.
Features: snake-like, structure of the lower surface.
Layered(St) are aqueous or mixed, look like a homogeneous gray layer. At low density, the Sun shines through them, and it has clear outlines. Drizzle can fall from stratus clouds, and in winter - ice needles, fine snow, and snow grains. The thickness of the layer is up to several hundred meters.
Types: foggy, torn.
Varieties: non-transparent, translucent, wavy.
Clouds of vertical development
Cumulus(Cu) dense clouds with sharply defined contours. They develop upward, forming dense white tops, similar to cauliflower, the bases of the clouds are relatively dark. Vertical thickness varies widely:
for flat ones - tens and hundreds of meters;
for powerful ones - more than 5 km.
These are water clouds (made up of droplets), so they do not produce precipitation (except in the tropics, where light rain can fall from powerful cumulus clouds).
Types: flat, medium, powerful, torn.
Varieties: radiating.
Features: hat, fall stripes.
Cumulonimbus(Cb) larger and darker, the result of further vertical development of the cumulus. The vertical thickness of cumulonimbus clouds can vary from 3 to 15 km. They greatly change the illumination (reduce it) as they block the Sun. These are mixed clouds: there are drops in the lower part, drops and crystals in the middle, and crystals in the upper part. It is Cb that is associated with showers, thunderstorms, squalls, and tornadoes. Rare in polar latitudes.
Types: bald, hairy.
Features: fall stripes, tufts, anvil, hump-like protrusions, cap, veil, collar, and occasionally trunk.
By origin genetic types of clouds are distinguished:
Intra-mass
a) convection clouds, b) clouds of stable masses.
Frontal
a) ascending clouds, b) orographic clouds.
In the first genetic type (intramass) there are convection clouds and clouds of stable air masses.
Convection clouds 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 type of turbulent movement, these are flat cumulus clouds, as well as fractus cumulus; when well-formed ascending currents of significant speed (3.6 m/s or more) occur, powerful cumulus and cumulonimbus clouds arise. In the middle layer, some types of altocumulus clouds are associated with convection: tower-shaped and flocculent.
Cumulus or convective clouds look like isolated cloud masses. They are highly developed vertically and have a small (average) horizontal extension.
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 upward and fall into layers of colder air (thermals). There they cool, the water vapor in them condenses, and clouds form (Figure 30). These bubbles, or convection cells, last 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 using photogrammetry from the ground and during observations in flight, a convective cloud consists of individual 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 flows is 40 jets per 1 km 2. The size of convective flows in powerful cumulus clouds is much larger than outside them (in the cloud d ~ 90 m, below it – 50 m).
Figure 30 – Scheme of the occurrence of thermal convection (Oblaka, 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; Zк
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, almost coinciding with the upper boundary of the cloud.
Layers with temperature inversions retard convection and prevent further development of cumulus cloud tops.
Dynamic convection is caused by the forced rise of warm air when flowing around an obstacle. The role of an obstacle can be played by a mountain ridge (Figure 31) or a frontal surface with a steep angle of inclination.
Convection clouds develop in unstable air masses (in cold air masses moving over a warm surface; local air masses over land in summer) are called cumuliformes (not cumulus).
Clouds of stable air masses arise due to air cooling from the underlying surface, dynamic turbulence and wave movements in the atmosphere. This subtype of clouds includes stratus, stratocumulus and altocumulus. They have a pronounced wavy structure, which is why they are called wavy.
Figure 31 – Scheme of the occurrence of dynamic convection when air flows over the ridge (Oblaka, 2007)
Wave movements of very different amplitudes and wavelengths are observed in the atmosphere. Under the influence of such movements, under certain conditions, wavy clouds can form, which have the appearance of a horizontally distributed (tens and hundreds of kilometers) layer consisting of disks, plates, and 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 shapes from areas of low pressure to areas of high pressure and their further transformation. An inversion layer forms beneath existing clouds 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 form.
Frontal clouds . In connection with fronts, huge cloud systems arise, stretching along the front line for thousands of kilometers and hundreds of kilometers wide. Such clouds are called upslide clouds. A front separates a flat wedge of cold air from a layer of warm air lying next to 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 thick cloud layer. Such clouds are called stratiform. The thickest clouds (several kilometers) are nimbostratus clouds. Further from the front line they give way to highly stratified, cirrus-stratified. At a distance of many hundreds of kilometers from the front line, ridges of cirrus clouds are observed. Frontal clouds may intensify as the front approaches the mountain range.
Figure 33 – Scheme of the formation of ascending sliding clouds (Oblaka, 2007)
In addition, there are:
Volcanic eruption clouds are cumulus clouds that appear over volcanoes during an eruption. They are distinguished by rapid development and abundant clubs. They consist of dust (ash) and water droplets, sometimes giving precipitation. Electrical phenomena may be associated with them.
Damming clouds (slowing down the horizontal transfer of air as it moves onto the underlying surface with increased friction, especially in front of mountain ranges and massifs).
Fire clouds are formed due to the formation of strong upward convection currents over large (forest) fires. Contain combustion products (smoke, soot, ash). They often have a gloomy appearance.
From the surface of the Earth, all clouds appear to be at approximately the same height. However, there can be huge distances between them, equal to several kilometers. But what are the highest and lowest of them? This post has all the information you need to become a cloud expert!
10. Stratus clouds (average height - 300-450 m)
Wikipedia information: Stratus clouds are low-level clouds characterized by horizontal layering with a uniform layer, in contrast to cumuliform clouds, which are formed by rising warm currents.
More specifically, the term "stratus" is used to describe flat, misty clouds at the bottom, ranging in color from dark gray to almost white.
9. Cumulus clouds (average height - 450-2000 m)
Wikipedia information: "Cumulus" is Latin for "heap, heap." Cumulus clouds are often described as "plump", "cotton-like" or "fluffy" in appearance and have a flat base.
Being low level clouds, they are usually less than 1000 meters in height unless they are a more vertical form of cumulus cloud. Cumulus clouds can appear alone, in lines, or in clusters.
8. Stratocumulus clouds (average height - 450-2000 m)
Wikipedia information: Stratocumulus clouds are a type of cloud characterized by large, dark, round masses, usually in the form of groups, lines or waves, the individual elements of which are larger than those of altocumulus clouds, forming at a lower altitude, usually below 2400 meters .
Weak convective air currents create shallow layers of clouds due to the drier, still air above them, preventing their further vertical development.
7. Cumulonimbus clouds (average height - 450-2000 m)
Wikipedia information: Cumulonimbus clouds are dense, towering vertical clouds associated with thunderstorms and atmospheric instability, formed from water vapor carried by powerful updrafts.
Cumulonimbus clouds can form alone, in clusters, or as a squall along a cold front. These clouds are capable of producing lightning and other dangerous severe weather such as tornadoes.
6. Nimbostratus clouds (average height - 900-3000 m)
Wikipedia information: Nimbostratus clouds usually produce precipitation over a large area. They have a diffuse base, usually located somewhere near the surface at the lower levels and at an altitude of about 3000 meters at the middle levels.
Although nimbostratus clouds are usually dark in color at the base, they are often illuminated from within when viewed from the Earth's surface.
5. Altostratus clouds (average height - 2000-7000 m)
Wikipedia information: Altostratus clouds are a type of mid-level cloud belonging to the stratiform physical category, which is characterized by a generally uniform layer whose color varies from gray to bluish-green.
They are lighter than nimbostratus clouds and darker than tall cirrostratus clouds. The Sun can be seen through thin altostratus clouds, but thicker clouds may have a denser, opaque structure.
4. Altocumulus clouds (average height - 2000-7000 m)
Wikipedia information: Altocumulus clouds are a type of mid-level cloud that belongs primarily to the stratocumulus physical category, characterized by spherical masses or ridges in layers or sheets, the individual elements of which are larger and darker than those of cirrocumulus clouds, and smaller. than that of stratocumulus clouds.
However, if the layers become flocculent due to increased instability of the air mass, then altocumulus clouds become more cumuliform in structure.
3. Cirrus clouds (average height - 5000-13,500 m)
Wikipedia information: Cirrus clouds are a type of atmospheric cloud typically characterized by thin, thread-like filaments.
The cloud filaments sometimes form into tufts of characteristic shapes known collectively as "mare's tails." Cirrus clouds are usually white or light gray in color.
2. Cirrostratus clouds (average level - 5000-13,500 m)
Wikipedia information: Cirrostratus clouds are a type of thin, whitish stratus clouds composed of ice crystals. They are difficult to detect and are capable of forming a halo when they take the form of a thin cirrostratus cloud.
1. Cirrocumulus clouds (average height - 5000-13,500 m)
Wikipedia information: Cirrocumulus clouds are one of the three main types of upper-level tropospheric clouds (the other two are cirrus and cirrostratus clouds). Like lower-level cumulus clouds, cirrocumulus clouds signify convection.
Unlike other tall cirrus and cirrostratus, cirrocumulus consists of a small number of transparent water droplets, although they are in a supercooled state.