The main source of energy for the vast majority of physical, chemical and biological processes in the atmosphere, hydrosphere and in the upper layers of the lithosphere is solar radiation, and therefore the ratio of components. . characterize its transformations in these shells.

T. b. are private formulations of the law of conservation of energy and are compiled for a section of the Earth's surface (T. b. of the earth's surface); for a vertical column passing through the atmosphere (T. b. atmosphere); for such a column passing through the atmosphere and the upper layers of the lithosphere, the hydrosphere (T. b. the Earth-atmosphere system).

T. b. earth's surface: R + P + F0 + LE = 0 is the algebraic sum of energy flows between an element of the earth's surface and the surrounding space. These streams include radiation (or residual radiation) R - between the absorbed short-wave solar radiation and long-wave effective radiation from the earth's surface. Positive or negative radiation balance is compensated by several heat fluxes. Since the earth's surface is usually not equal to the air temperature, heat arises between the underlying surface and the atmosphere. A similar heat flux F0 is observed between the earth's surface and deeper layers of the lithosphere or hydrosphere. At the same time, the heat flux in the soil is determined by molecular thermal conductivity, while in water bodies, as , it is more or less turbulent. The heat flux F0 between the surface of the reservoir and its deeper layers is numerically equal to the change in the heat content of the reservoir over a given time and the heat transfer by currents in the reservoir. Essential in T. b. the earth's surface usually has heat per LE, which is defined as the mass of evaporated water E per the heat of evaporation L. The value of LE depends on the moistening of the earth's surface, its temperature, air humidity and the intensity of turbulent heat transfer in the surface air layer, which determines the transfer of water from the earth's surface to atmosphere.

Equation T. b. atmosphere has: Ra + Lr + P + Fa = DW.

T. b. atmosphere is composed of its radiation balance Ra; heat input or output Lr during phase transformations of water in the atmosphere (r - precipitation); the arrival or consumption of heat P, due to the turbulent heat exchange of the atmosphere with the earth's surface; heat gain or loss Fa caused by heat exchange through the vertical walls of the column, which is associated with ordered atmospheric motions and macroturbulence. In addition, in the equation T. b. atmosphere enters DW, equal to the change in heat content inside the column.

Equation T. b. systems Earth - atmosphere corresponds to the algebraic sum of the terms of the equations T. b. earth's surface and atmosphere. Components of T. b. Earth's surface and atmosphere for various regions of the globe are determined by meteorological observations (at actinometric stations, at special stations in the sky, and on Earth's meteorological satellites) or by climatological calculations.

The latitudinal values ​​of the components of T. b. the earth's surface for the oceans, land and Earth, and T. b. atmospheres are given in tables 1, 2, where the values ​​of the members of T. b. are considered positive if they correspond to the arrival of heat. Since these tables refer to average annual conditions, they do not include terms characterizing changes in the heat content of the atmosphere and the upper layers of the lithosphere, since for these conditions they are close to zero.

For the Earth as, together with the atmosphere, T. b. presented on . A unit surface of the outer boundary of the atmosphere receives a flux of solar radiation equal to an average of about 250 kcal / cm2 in, of which about ═ is reflected into the world, and 167 kcal / cm2 per year is absorbed by the Earth (arrow Qs on rice.). The earth's surface reaches short-wave radiation equal to 126 kcal/cm2 per year; Of this amount, 18 kcal/cm2 per year is reflected and 108 kcal/cm2 per year is absorbed by the earth's surface (arrow Q). The atmosphere absorbs 59 kcal/cm2 per year of shortwave radiation, that is, much less than the earth's. The effective long-wavelength of the Earth's surface is 36 kcal/cm2 per year (arrow I), so the radiation balance of the earth's surface is 72 kcal/cm2 per year. The long-wave radiation of the Earth into the world space is equal to 167 kcal/cm2 per year (arrow Is). Thus, the Earth's surface receives about 72 kcal/cm2 per year of radiant energy, which is partially spent on the evaporation of water (circle LE) and partially returned to the atmosphere through turbulent heat transfer (arrow P).

Tab. 1. - Heat balance of the earth's surface, kcal/cm2 year

degrees

Earth average

R══════LE ═════════Р════Fo

R══════LE══════R

═R════LE═══════R═════F0

70-60 north latitude

0-10 south latitude

Earth as a whole

23-══33═══-16════26

29-══39═══-16════26

51-══53═══-14════16

83-══86═══-13════16

113-105═══- 9═══════1

119-══99═══- 6═-14

115-══80═══- 4═-31

115-══84═══- 4═-27

113-104═══-5════-4

101-100═══- 7══════6

82-══80═══-9═══════7

57-══55═══-9═══════7

28-══31═══-8══════11

82-══74═══-8═══════0

20═══-14══- 6

30═══-19══-11

45═══-24══-21

60═══-23══-37

69═══-20══-49

71═══-29══-42

72═══-48══-24

72═══-50══-22

73═══-41══-32

70═══-28══-42

62═══-28══-34

41═══-21══-20

31═══-20══-11

49═══-25══-24

21-20══- 9═══════8

30-28═-13═════11

48-38═-17══════7

73-59═-23══════9

96-73═-24══════1

106-81═-15═-10

105-72══- 9═-24

105-76══- 8═-21

104-90═-11═══-3

94-83═-15══════4

80-74═-12══════6

56-53══- 9══════6

28-31══- 8════11

72-60═-12══════0

Data on the components of T. b. are used in the development of many problems of climatology, land hydrology, and oceanology; they are used to substantiate numerical models of climate theory and to empirically test the results of applying these models. Materials about T. b. play big

The radiation balance is called the income-expenditure of radiant energy absorbed and emitted by the underlying surface, the atmosphere or the earth-atmosphere system for various periods of time (6, p. 328).

The input part of the underlying surface radiation balance R is made up of direct solar and diffuse radiation, as well as atmospheric counterradiation absorbed by the underlying surface. The expenditure part is determined by the loss of heat due to the intrinsic thermal radiation of the underlying surface (6, p. 328).

Radiation balance equation:

R=(Q+q) (1-A)+d-

where Q is the flux (or sum) of direct solar radiation, q is the flux (or sum) of scattered solar radiation, A is the albedo of the underlying surface, is the flux (or sum) of atmospheric counter-radiation, and is the flux (or sum) of the intrinsic thermal radiation of the underlying surface, e is the absorptive capacity of the underlying surface (6, p. 328).

The radiation balance of the earth's surface for the year is positive everywhere on Earth, except for the ice plateaus of Greenland and Antarctica (Fig. 5). This means that the annual influx of absorbed radiation is greater than the effective radiation for the same time. But this does not mean at all that the earth's surface is getting warmer every year. The excess of absorbed radiation over radiation is balanced by the transfer of heat from the earth's surface into the air by thermal conduction and during phase transformations of water (during evaporation from the earth's surface and subsequent condensation in the atmosphere).

Consequently, for the earth's surface there is no radiative equilibrium in the receipt and return of radiation, but there is a thermal equilibrium: the influx of heat to the earth's surface both by radiative and non-radiative ways is equal to its return by the same methods.

Heat balance equation:

where the value of the radiative heat flux is R, the turbulent heat flux between the underlying surface and the atmosphere is P, the heat flux between the underlying surface and the underlying layers is A, and the heat consumption for evaporation (or heat release during condensation) is LE (L is the latent heat of evaporation, E is the rate of evaporation or condensation) (4, p. 7).

In accordance with the inflow and outflow of heat in relation to the underlying surface, the components of the heat balance can have positive or negative values. In a long-term conclusion, the average annual temperature of the upper layers of soil and water of the World Ocean is considered constant. Therefore, the vertical and horizontal heat transfer in the soil and in the World Ocean as a whole can practically be equated to zero.

Thus, in the long-term derivation, the annual heat balance for the land surface and the World Ocean is made up of the radiation balance, heat losses for evaporation, and turbulent heat exchange between the underlying surface and the atmosphere (Figs. 5, 6). For individual parts of the ocean, in addition to the indicated components of the heat balance, it is necessary to take into account the transfer of heat by sea currents.

Rice. five. The radiation balance of the Earth and the arrival of solar radiation for the year

Thermal balance ns Earth, the ratio of the income and consumption of energy (radiant and thermal) on the earth's surface, in the atmosphere and in the Earth-atmosphere system. The main source of energy for the vast majority of physical, chemical and biological processes in the atmosphere, hydrosphere and in the upper layers of the lithosphere is solar radiation, therefore, the distribution and ratio of the components of T. b. characterize its transformations in these shells.

T. b. are private formulations of the law of conservation of energy and are compiled for a section of the Earth's surface (T. b. of the earth's surface); for a vertical column passing through the atmosphere (T. b. atmosphere); for the same column passing through the atmosphere and the upper layers of the lithosphere or the hydrosphere (T. b. the Earth-atmosphere system).

Equation T. b. earth surface: R+P+F0+LE= 0 is the algebraic sum of energy flows between an element of the earth's surface and the surrounding space. These streams include radiation balance (or residual radiation) R- the difference between the absorbed short-wave solar radiation and long-wave effective radiation from the earth's surface. The positive or negative value of the radiation balance is compensated by several heat fluxes. Since the temperature of the earth's surface is usually not equal to the temperature of the air, between underlying surface and the atmosphere creates a heat flux R. Similar heat flow F 0 is observed between the earth's surface and deeper layers of the lithosphere or hydrosphere. In this case, the heat flux in the soil is determined by the molecular thermal conductivity, while in water bodies heat exchange, as a rule, has a turbulent character to a greater or lesser extent. heat flow F 0 between the surface of the reservoir and its deeper layers is numerically equal to the change in the heat content of the reservoir over a given time interval and the transfer of heat by currents in the reservoir. Essential value in T. b. the earth's surface usually has a heat loss for evaporation L.E., which is defined as the product of the mass of evaporated water E to the heat of evaporation L. Value LE depends on the moistening of the earth's surface, its temperature, air humidity and the intensity of turbulent heat transfer in the surface layer of air, which determines the rate of transfer of water vapor from the earth's surface to the atmosphere.

Equation T. b. atmosphere looks like: Ra+ L r+P+ Fa=D W.

T. b. atmosphere is made up of its radiation balance R a ; heat input or output L r during phase transformations of water in the atmosphere (r - the amount of precipitation); the arrival or consumption of heat P, due to the turbulent heat exchange of the atmosphere with the earth's surface; heat input or output F a , caused by heat transfer through the vertical walls of the column, which is associated with ordered atmospheric motions and macroturbulence. In addition, in the equation T. b. atmosphere includes a term D W, equal to the change in heat content inside the column.

Equation T. b. systems Earth - atmosphere corresponds to the algebraic sum of the terms of the equations T. b. earth's surface and atmosphere. Components of T. b. Earth's surface and atmosphere for various regions of the globe are determined by meteorological observations (at actinometric stations, at special stations in the sky, and on Earth's meteorological satellites) or by climatological calculations.

The average latitudinal values ​​of the components of T. b. the earth's surface for the oceans, land and Earth, and T. b. atmospheres are given in tables 1, 2, where the values ​​of the members of T. b. are considered positive if they correspond to the arrival of heat. Since these tables refer to average annual conditions, they do not include terms characterizing changes in the heat content of the atmosphere and the upper layers of the lithosphere, since for these conditions they are close to zero.

For the Earth as a planet, together with the atmosphere, the scheme of T. b. shown in fig. A unit of surface of the outer boundary of the atmosphere receives a flux of solar radiation equal to an average of about 250 kcal/cm 2 per year, of which about 167 kcal/cm 2 per year is absorbed by the Earth (arrow Q s on rice. ). The earth's surface reaches short-wave radiation equal to 126 kcal/cm 2 per year; eighteen kcal/cm 2 per year of this amount is reflected, and 108 kcal/cm 2 per year is absorbed by the earth's surface (arrow Q). The atmosphere absorbs 59 kcal/cm 2 short-wave radiation per year, that is, much less than the earth's surface. The effective long-wave radiation of the Earth's surface is 36 kcal/cm 2 per year (arrow I), therefore, the radiation balance of the earth's surface is 72 kcal/cm 2 per year. The long-wave radiation of the Earth into the world space is equal to 167 kcal/cm 2 per year (arrow I s). Thus, the surface of the Earth receives about 72 kcal/cm 2 per year of radiant energy, which is partially spent on the evaporation of water (circle LE) and is partially returned to the atmosphere through turbulent heat transfer (arrow R).

Tab. 1. - Thermal balance of the earth's surface, kcal/cm 2 year

Latitude, degrees			Earth average
	R LE R F o	R LE R	R LE R F 0
70-60 north latitude 0-10 south latitude Earth as a whole

Data on the components of T. b. are used in the development of many problems of climatology, land hydrology, and oceanology; they are used to substantiate numerical models of climate theory and to empirically test the results of applying these models. Materials about T. b. play an important role in the study of climate change, they are also used in calculations of evaporation from the surface of river basins, lakes, seas and oceans, in studies of the energy regime of sea currents, for the study of snow and ice covers, in plant physiology for the study of transpiration and photosynthesis, in physiology animals to study the thermal regime of living organisms. Data about T. b. were also used to study geographic zoning in the works of the Soviet geographer A. A. Grigoriev.

Tab. 2. - The heat balance of the atmosphere, kcal/cm 2 year

Latitude, degrees
70-60 north latitude 0-10 south latitude Earth as a whole

Lit.: Atlas of the heat balance of the globe, ed. M. I. Budyko. Moscow, 1963. Budyko M.I., Climate and life, L., 1971; Grigoriev A. A., Patterns of the structure and development of the geographical environment, M., 1966.

The main source of energy for all processes occurring in the biosphere is solar radiation. The atmosphere surrounding the Earth weakly absorbs short-wave radiation from the Sun, which mainly reaches the earth's surface. Some of the solar radiation is absorbed and scattered by the atmosphere. The absorption of incident solar radiation is due to the presence of ozone, carbon dioxide, water vapor, and aerosols in the atmosphere.[ ...]

Under the influence of the incident solar flux, as a result of its absorption, the earth's surface heats up and becomes a source of long-wave (LW) radiation directed towards the atmosphere. The atmosphere, on the other hand, is also a source of DW radiation directed towards the Earth (the so-called atmospheric counter-radiation). In this case, mutual heat exchange occurs between the earth's surface and the atmosphere. The difference between the HF radiation absorbed by the earth's surface and the effective radiation is called the radiation balance. The transformation of the energy of HF solar radiation when it is absorbed by the earth's surface and the atmosphere, heat exchange between them constitute the heat balance of the Earth.[ ...]

The main feature of the radiation regime of the atmosphere is the greenhouse effect, which consists in the fact that short-wave radiation mostly reaches the earth's surface, causing it to heat up, and LW radiation from the Earth is delayed by the atmosphere, while reducing the heat transfer of the Earth into space. The atmosphere is a kind of heat-insulating shell that prevents the Earth from cooling. An increase in the percentage of CO2, H20 vapor, aerosols, etc. will enhance the greenhouse effect, which leads to an increase in the average temperature of the lower atmosphere and climate warming. The main source of thermal radiation of the atmosphere is the earth's surface.[ ...]

The intensity of solar radiation absorbed by the earth's surface and the atmosphere is 237 W/m2, of which 157 W/m2 is absorbed by the earth's surface, and 80 W/m2 by the atmosphere. The heat balance of the Earth is presented in general form in Fig. 6.15.[ ...]

The radiation balance of the earth's surface is 105 W/m2, and the effective radiation from it is equal to the difference between the absorbed radiation and the radiation balance and is 52 W/m2. The energy of the radiation balance is spent on the turbulent heat exchange of the Earth with the atmosphere, which is 17 W/m2, and on the process of water evaporation, which is 88 W/m2.[ ...]

The scheme of heat transfer of the atmosphere is shown in fig. 6.16. As can be seen from this diagram, the atmosphere receives thermal energy from three sources: from the Sun, in the form of absorbed HF radiation with an intensity of approximately 80 W/m2; heat from condensation of water vapor coming from the earth's surface and equal to 88 W/m2; turbulent heat exchange between the Earth and the atmosphere (17 W/m2).[ ...]

The sum of heat transfer components (185 W/m) is equal to the heat losses of the atmosphere in the form of DW radiation into outer space. An insignificant part of the incident solar radiation, which is significantly less than the given components of the heat balance, is spent on other processes occurring in the atmosphere.[ ...]

The difference in evaporation from the continents and the surfaces of the seas and oceans is compensated by the processes of mass transfer of water vapor through air currents and the flow of rivers flowing into the water areas of the globe.

The heat balance of the Earth, the atmosphere and the earth's surface Over a long period of time, the heat balance is zero, that is, the Earth is in thermal equilibrium. I - shortwave radiation, II - longwave radiation, III - non-radiative exchange.

Electromagnetic Radiation Radiation or radiation is a form of matter other than matter. A special case of radiation is visible light; but radiation also includes gamma rays that are not perceived by the eye, x-rays, ultraviolet and infrared radiation, radio waves, including television waves.

Characteristics of electromagnetic waves Radiation propagates in all directions from the emitter source in the form of m electromagnetic waves with the speed of light in a vacuum of about 300,000 km/s. Wavelength is the distance between adjacent maxima (or minima). m The oscillation frequency is the number of oscillations per second.

Wavelengths Ultraviolet radiation - wavelength from 0.01 to 0.39 microns. It is invisible, that is, it is not perceived by the eye. Visible light perceived by the eye, wavelengths 0.40 0.76 microns. Waves around 0.40 µm are purple, waves around 0.76 µm are red. Between 0.40 and 0.76 microns is the light of all colors of the visible spectrum. Infrared radiation - waves > 0.76 microns and up to several hundred microns are invisible to the human eye. In meteorology, it is customary to distinguish shortwave and longwave radiation. Shortwave is called radiation in the wavelength range from 0.1 to 4 microns. P

Wavelengths When white light is decomposed by a prism into a continuous spectrum, the colors in it gradually pass one into another. It is generally accepted that within certain limits of wavelengths (nm) radiation has the following colors: 390-440 - violet 440-480 blue 480-510 - blue 510-550 - green 550-575 yellow-green 575-585 yellow 585-620 - orange 630-770 - red

Wavelength perception The human eye is most sensitive to yellow-green radiation with a wavelength of about 555 nm. There are three radiation zones: blue-violet (wavelength 400-490 nm), green (length 490-570 nm) red (length 580-720 nm). These spectral zones are also the zones of predominant spectral sensitivity of the eye detectors and three layers of color film.

ABSORPTION OF SOLAR RADIATION IN THE ATMOSPHERE About 23% of direct solar radiation is absorbed in the atmosphere. e Absorption is selective: different gases absorb radiation in different parts of the spectrum and to different degrees. Nitrogen absorbs R very small wavelengths in the ultraviolet part of the spectrum. The energy of solar radiation in this part of the spectrum is completely negligible, so the absorption by nitrogen has practically no effect on the flux of solar radiation. Oxygen absorbs more, but also very little - in two narrow sections of the visible part of the spectrum and in the ultraviolet part. Ozone absorbs ultraviolet and visible solar radiation. There is very little of it in the atmosphere, but it absorbs ultraviolet radiation in the upper layers of the atmosphere so strongly that waves shorter than 0.29 microns are not observed at all in the solar spectrum near the earth's surface. Its absorption of solar radiation by ozone reaches 3% of direct solar radiation.

ABSORPTION OF SOLAR RADIATION IN THE ATMOSPHERE CO 2 absorbs strongly in the infrared spectrum, but its content in the atmosphere is very small, so its absorption of direct solar radiation is generally small. Water vapor is the main absorber of radiation, concentrated in the troposphere. Absorbs radiation in the visible and near infrared regions of the spectrum. Clouds and atmospheric impurities (aerosol particles) absorb solar radiation in different parts of the spectrum, depending on the composition of the impurities. Water vapor and aerosols absorb about 15%, clouds 5% of radiation.

Heat balance of the Earth Scattered radiation passes through the atmosphere and is scattered by gas molecules. Such radiation is 70% in the polar latitudes and 30% in the tropics.

The heat balance of the Earth 38% of the scattered radiation returns to space. It gives the blue color to the sky and diffuses light before and after sunset.

Heat balance of the Earth Direct + diffuse = total R 4% is reflected by the atmosphere 10% is reflected by the earth's surface 20% is converted into thermal energy 24% is spent on air heating Total heat loss through the atmosphere is 58% of all received

Air advection Movement of air in a horizontal direction. We can talk about advection: air masses, heat, water vapor, moment of motion, vortex of speed, etc. Atmospheric phenomena that occur as a result of advection are called advective: advective fogs, advective thunderstorms, advective frosts, etc.

ALBEDO 1. In a broad sense, the reflectivity of the surface: water, vegetation (forest, steppe), arable land, clouds, etc. For example, Albedo of forest crowns is 10 - 15%, grass - 20 - 25%, sand - 30 - 35%, freshly fallen snow - 50 - 75% or more. 2. Albedo of the Earth - the percentage of solar radiation reflected by the globe together with the atmosphere back into the world space, to the solar radiation that arrived at the boundary of the atmosphere. A = O / P The return of radiation by the Earth occurs by reflection from the earth's surface and clouds of long-wave radiation, as well as scattering of direct short-wave radiation by the atmosphere. The snow surface has the highest reflectivity (85%). Earth's albedo is about 42%

Consequences of the inversion When the normal process of convection stops, the lower layer of the atmosphere is polluted Winter smoke in the city of Shanghai, the boundary of the vertical distribution of air is clearly visible

Temperature inversion The sinking of cold air creates a steady state of the atmosphere. The smoke from the chimney cannot overcome the descending air mass

The course of atmospheric air pressure. 760 mm tr. Art. = 1033 g Pa Daily variation of atmospheric pressure

Water in the atmosphere The total volume is 12 - 13 thousand km 3 of water vapor. Evaporation from the surface of the ocean 86% Evaporation from the surface of the continents 14% The amount of water vapor decreases with height, but the intensity of this process depends on: surface temperature and humidity, wind speed and atmospheric pressure

Atmospheric Humidity Characteristics Air humidity is the amount of water vapor in the air. Absolute air humidity - the content of water vapor (g) per 1 m 3 of air or its pressure (mm Hg) Relative humidity - the degree of saturation of air with water vapor (%)

Atmospheric Humidity Characteristics Maximum moisture saturation is the limit of water vapor content in the air at a given temperature. Dew point - the temperature at which the water vapor contained in the air saturates it (τ)

Atmospheric humidity characteristics Evaporation - the actual evaporation from a given surface at a given temperature Evaporation - the maximum possible evaporation at a given temperature

Atmospheric Humidity Characteristics Evaporation is equal to evapotranspiration over water, and much less over land. At high temperatures, absolute humidity increases, relative humidity remains the same if there is not enough water.

Atmospheric Humidity Characteristics In cold air, with low absolute humidity, the relative humidity can reach 100%. Precipitation falls when the dew point is reached. In cold climates, even at very low relative humidity.

Causes of changes in air humidity 1. ZONALITY Absolute humidity decreases from the equator (20 - 30 mm) to the poles (1 - 2 mm). Relative humidity changes little (70 - 80%).

Causes of changes in air humidity 2. The annual course of absolute humidity corresponds to the course of temperatures: the warmer, the higher

INTERNATIONAL CLASSIFICATION OF CLOUDS Clouds are divided into 10 main forms (genera) according to their appearance. In the main genera, there are: species, varieties, and other features; as well as intermediate forms. g Cloudiness is measured in points: 0 - cloudless; 10 - the sky is completely covered with clouds.

INTERNATIONAL CLASSIFICATION OF CLOUD Cloud genera Russian name Latin name I Cirrus Cirrus (Ci) II Cirrocumulus Cirrocumulus (Cc) III Cirrostratus Cirrostratus (Cs) IV Altocumulus Altocumulus (Ac) V Altostratus Altostratus (As) VI Nimbostratus (Ns) ) VII Stratocumulus Stratocumulus (Sc) VIII Stratocumulus Stratus (St) IX Cumulus Cumulus (Cu) X Cumulonimbus Cumulonimbus (Cb) Stage height H = 7 – 18 km H = 2 – 8 km H = up to 2 km

Clouds of the lower tier. Stratostratus clouds have the same origin as Altostratus. However, their layer is several kilometers. These clouds are in the lower, middle and often upper tiers. In the upper part they consist of tiny drops and snowflakes, in the lower part they can contain large drops and snowflakes. Therefore, the layer of these clouds has a dark gray color. The sun and moon do not shine through it. As a rule, overcast rain or snow falls from stratocinimbus clouds, reaching the earth's surface.

Mid-tier clouds Altocumulus clouds are cloud layers or ridges of white or gray color (or both). These are rather thin clouds, more or less obscuring the sun. Layers or ridges consist of flat shafts, disks, plates, often arranged in rows. Optical phenomena appear in them - crowns, iridescence - iridescent coloring of the edges of clouds directed towards the sun. Irisa indicates that altocumulus clouds are composed of very small, uniform droplets, usually supercooled.

Mid-tier clouds Optical phenomena in clouds Altocumulus Clouds Crowns in clouds Cloud iridescence Halo

Upper Clouds These are the highest clouds in the troosphere, form at the lowest temperatures, and are composed of ice crystals, are white, translucent, and obscure little sunlight.

Phase composition of clouds Water (droplet) clouds, consisting only of drops. They can exist not only at positive temperatures, but also at negative ones (-100 C and below). In this case, the droplets are in a supercooled state, which is quite usual under atmospheric conditions. c Mixed clouds consisting of a mixture of supercooled clouds and ice crystals. They can exist, as a rule, at temperatures from -10 to -40°C. Ice (crystalline) clouds, consisting only of ice and crystals. They predominate, as a rule, at temperatures below 30°C.