The heat balance of the earth as a whole. Radiation and heat balances. Seasonal fluctuations in the radiation balance

The difference between absorbed solar radiation and effective radiation is the radiation balance, or residual radiation of the earth's surface (B). The radiation balance, averaged over the entire surface of the Earth, can be written as the formula B = Q * (1 - A) - E eff or B = Q - R k - E eff. Figure 24 shows an approximate percentage various kinds radiation involved in the radiation and heat balance. It is obvious that the surface of the Earth absorbs 47% of all the radiation that has arrived on the planet, and the effective radiation is 18%. Thus, the radiation balance, averaged over the surface of the entire Earth, is positive and amounts to 29%.

Rice. 24. Scheme of radiation and heat balances of the earth's surface (according to K. Ya. Kondratiev)

The distribution of the radiation balance over the earth's surface is highly complex. Knowledge of the patterns of this distribution is extremely important, since under the influence of residual radiation the temperature regime of the underlying surface and the troposphere and the Earth's climate as a whole are formed. Analysis of maps of the radiation balance of the earth's surface for the year (Fig. 25) leads to the following conclusions.

The annual sum of the radiation balance of the Earth's surface is almost everywhere positive, with the exception of the ice plateaus of Antarctica and Greenland. Its annual values ​​zonally and regularly decrease from the equator to the poles in accordance with the main factor - total radiation. Moreover, the difference in the values ​​of the radiation balance between the equator and the poles is more significant than the difference in the values ​​of the total radiation. Therefore, the zonality of the radiation balance is very pronounced.

The next regularity of the radiation balance is its increase during the transition from land to the ocean with discontinuities and mixing of isolines along the coast. This feature is better pronounced in the equatorial-tropical latitudes and gradually smoothes out to the polar ones. The greater radiation balance over the oceans is explained by the lower albedo of water, especially in the equatorial-tropical latitudes, and by the reduced effective radiation due to the lower surface temperature of the Ocean and the significant moisture content of the air and cloudiness. Due to the increased values ​​of the radiation balance and the large area of ​​the Ocean on the planet (71%), it is he who plays the leading role in the thermal regime of the Earth.And the difference in the radiation balance of the oceans and continents determines their constant and deep mutual influence on each other at all latitudes.

Rice. 25. Radiation balance of the earth's surface for the year [MJ / (m 2 X year)] (according to S. P. Khromov and M. A. Petrosyants)

Seasonal changes in the radiation balance in the equatorial-tropical latitudes are small (Fig. 26, 27). This results in small fluctuations in temperature throughout the year. Therefore, the seasons of the year are determined there not by the course of temperatures, but by the annual rainfall regime. In extratropical latitudes, there are qualitative changes in the radiation balance from positive to negative values during a year. In summer, over vast expanses of temperate and partly high latitudes, the values ​​​​of the radiation balance are significant (for example, in June on land near the Arctic Circle they are the same as in tropical deserts) and its fluctuations in latitudes are relatively small. This is reflected in the temperature regime and, accordingly, in the weakening of the interlatitudinal circulation during this period. In winter, over large expanses, the radiation balance is negative: the line of zero radiation balance of the coldest month passes over the land approximately along 40 ° latitude, over the oceans - along 45 °. Different thermobaric conditions in winter lead to the activation of atmospheric processes in temperate and subtropical latitude zones. The negative radiation balance in winter in temperate and polar latitudes is partly compensated by the influx of heat with air and water masses from the equatorial-tropical latitudes. In contrast to low latitudes in temperate and high latitudes, the seasons of the year are determined primarily by thermal conditions that depend on the radiation balance.

Rice. 26. Radiation balance of the earth's surface for June [in 10 2 MJ / (m 2 x M es.) |

In the mountains of all latitudes, the distribution of the radiation balance is complicated by the influence of height, duration of snow cover, insolation exposure of slopes, cloudiness, etc. In general, despite the increased values ​​of total radiation in the mountains, the radiation balance is lower there due to the albedo of snow and ice, an increase in the proportion of effective radiation and other factors.

The Earth's atmosphere has its own radiation balance. The arrival of radiation into the atmosphere is due to the absorption of both short-wave solar radiation and long-wave terrestrial radiation. Radiation is consumed by the atmosphere with counter radiation, which is completely compensated by terrestrial radiation, and due to outgoing radiation. According to experts, the radiation balance of the atmosphere is negative (-29%).

In general, the radiation balance of the Earth's surface and atmosphere is 0, i.e., the Earth is in a state of radiative equilibrium. However, the excess of radiation on the Earth's surface and the lack of it in the atmosphere make one ask the question: why, with an excess of radiation, the Earth's surface does not incinerate, and the atmosphere, with its deficiency, does not freeze to a temperature of absolute zero? The fact is that between the surface of the Earth and the atmosphere (as well as between the surface and deep layers of the Earth and water) there are non-radiative methods of heat transfer. The first one is molecular thermal conductivity and turbulent heat transfer (H), during which the atmosphere is heated and heat is redistributed in it vertically and horizontally. The deep layers of the earth and water are also heated. The second is active heat exchange, which occurs when water passes from one phase state into another: during evaporation, heat is absorbed, and during condensation and sublimation of water vapor, the latent heat of vaporization (LE) is released.

It is non-radiative methods of heat transfer that balance the radiation balances of the earth's surface and atmosphere, bringing both to zero and preventing overheating of the surface and supercooling of the Earth's atmosphere. The earth's surface loses 24% of radiation as a result of water evaporation (and the atmosphere, respectively, receives the same amount due to subsequent condensation and sublimation of water vapor in the form of clouds and fogs) and 5% of radiation when the atmosphere is heated from the earth's surface. In total, this amounts to the very 29% of radiation that is excessive on the earth's surface and which is lacking in the atmosphere.

Rice. 27. Radiation balance of the earth's surface for December [in 10 2 MJ / (m 2 x M es.)]

Rice. 28. Components of the heat balance of the earth's surface in the daytime (according to S. P. Khromov)

The algebraic sum of all incomes and expenditures of heat on the earth's surface and in the atmosphere is called the heat balance; the radiation balance is thus the most important component of the heat balance. The equation for the heat balance of the earth's surface has the form:

B – LE – P±G = 0,

where B is the radiation balance of the earth's surface, LE is the heat consumption for evaporation (L is the specific heat of evaporation, £ is the mass of evaporated water), P is the turbulent heat exchange between the underlying surface and the atmosphere, G is the heat exchange with the underlying surface (Fig. 28). The loss of surface heat for heating the active layer during the day and summer is almost completely compensated by its flow back from the depths to the surface at night and in winter, therefore, the average long-term annual temperature of the upper layers of soil and water of the World Ocean is considered constant and G for almost any surface can be considered equal to zero. Therefore, in the long-term conclusion, the annual heat balance of the land surface and the World Ocean is spent on evaporation and heat exchange between the underlying surface and the atmosphere.

The distribution of heat balance over the Earth's surface is more complex than that of radiation due to numerous factors affecting it: cloudiness, precipitation, surface heating, etc. At different latitudes, the heat balance values ​​differ from 0 in one direction or another: at high latitudes it negative, and in low - positive. The lack of heat in the northern and southern polar regions is compensated by its transfer from tropical latitudes mainly with the help of ocean currents and air masses, thereby establishing thermal equilibrium between different latitudes of the earth's surface.

The heat balance of the atmosphere is written as follows: –B + LE + P = 0.

Obviously, the mutually complementary thermal regimes of the Earth's surface and atmosphere balance each other: all solar radiation entering the Earth (100%) is balanced by the loss of Earth's radiation due to reflection (30%) and radiation (70%), therefore, in general, thermal The balance of the Earth, like the radiation one, is equal to 0. The Earth is in radiant and thermal equilibrium, and any violation of it can lead to overheating or cooling of our planet.

The nature of the heat balance and its energy level determine the features and intensity of most of the processes occurring in the geographic envelope, and above all the thermal regime of the troposphere.

The earth receives heat by absorbing short-wave solar radiation in the atmosphere, and especially on the earth's surface. Solar radiation is practically the only source of heat in the "atmosphere-earth" system. Other heat sources (heat released during the decay of radioactive elements inside the Earth, gravitational heat, etc.) in total give only one five thousandth of the heat that enters the upper boundary of the atmosphere from solar radiation So and when compiling the heat balance equation, they can be ignored .

Heat is lost with short-wave radiation leaving the world space, reflected from the atmosphere Soa and from the earth's surface SOP, and due to the effective radiation of long-wave radiation Ee by the earth's surface and radiation of the atmosphere Еa.

Thus, at the upper boundary of the atmosphere, the heat balance of the Earth as a planet consists of radiant (radiative) heat transfer:

SO - Soa - Sop - Ee - Ea = ?Se, (1)

where? Se, the change in the heat content of the "atmosphere - Earth" system over a period of time? t.

Consider the terms of this equation for the annual period. The flux of solar radiation at the average distance of the Earth from the Sun is approximately equal to 42.6-10° J/(m2-year). From this flow, the Earth receives an amount of energy equal to the product of the solar constant I0 and the cross-sectional area of ​​the Earth pR2, i.e., I0 pR2, where R is the average radius of the Earth. Under the influence of the Earth's rotation, this energy is distributed over the entire surface of the globe, equal to 4pR2. Consequently, the average value of the solar radiation flux to the horizontal surface of the Earth, without taking into account its attenuation by the atmosphere, is Iо рR2/4рR3 = Iо/4, or 0.338 kW/m2. For a year, about 10.66-109 J, or 10.66 GJ of solar energy, is received on average for each square meter of the surface of the outer boundary of the atmosphere, i.e. Io = 10.66 GJ / (m2 * year).

Consider the expenditure side of equation (1). The solar radiation that has arrived at the outer boundary of the atmosphere partially penetrates the atmosphere, and is partially reflected by the atmosphere and the earth's surface into the world space. According to the latest data, the average albedo of the Earth is estimated at 33%: it is the sum of reflection from clouds (26%) and reflection from the underlying surface (7:%). Then the radiation reflected by the clouds Soa = 10.66 * 0.26 = 2.77 GJ / (m2 * year), the earth's surface - SOP = 10.66 * 0.07 = 0.75 GJ / (m2 * year) and in general, the Earth reflects 3.52 GJ/(m2*year).

The earth's surface, heated as a result of the absorption of solar radiation, becomes a source of long-wave radiation that heats the atmosphere. The surface of any body that has a temperature above absolute zero continuously radiates thermal energy. The earth's surface and atmosphere are no exception. According to the Stefan-Boltzmann law, the intensity of radiation depends on the temperature of the body and its emissivity:

E = wT4, (2)

where E is the radiation intensity, or self-radiation, W / m2; c is the emissivity of the body relative to a completely black body, for which c = 1; y - Stefan's constant - Boltzmann, equal to 5.67 * 10-8 W / (m2 * K4); T is the absolute body temperature.

Values ​​for various surfaces range from 0.89 (smooth water surface) to 0.99 (dense green grass). On average, for the earth's surface, v is taken equal to 0.95.

The absolute temperatures of the earth's surface are between 190 and 350 K. At such temperatures, the emitted radiation has wavelengths of 4-120 microns and, therefore, it is all infrared and is not perceived by the eye.

The intrinsic radiation of the earth's surface - E3, calculated by formula (2), is equal to 12.05 GJ / (m2 * year), which is 1.39 GJ / (m2 * year), or 13% higher than the solar radiation that arrived at the upper boundary of the atmosphere S0. Such a large return of radiation by the earth's surface would lead to its rapid cooling, if this were not prevented by the absorption of solar and atmospheric radiation by the earth's surface. Infrared terrestrial radiation, or own radiation of the earth's surface, in the wavelength range from 4.5 to 80 microns is intensively absorbed by atmospheric water vapor and only in the range of 8.5 - 11 microns passes through the atmosphere and goes into world space. In turn, atmospheric water vapor also emits invisible infrared radiation, most of which is directed down to the earth's surface, and the rest goes into world space. Atmospheric radiation coming to the earth's surface is called the counter radiation of the atmosphere.

From the counter radiation of the atmosphere, the earth's surface absorbs 95% of its magnitude, since, according to Kirchhoff's law, the radiance of a body is equal to its radiant absorption. Thus, the counterradiation of the atmosphere is an important source of heat for the earth's surface in addition to the absorbed solar radiation. The counter radiation of the atmosphere cannot be directly determined and is calculated by indirect methods. The counter radiation of the atmosphere absorbed by the earth's surface Eza = 10.45 GJ / (m2 * year). With respect to S0, it is 98%.

The counter radiation is always less than that of the earth. Therefore, the earth's surface loses heat due to the positive difference between its own and counter radiation. The difference between the self-radiation of the earth's surface and the counter-radiation of the atmosphere is called the effective radiation (Ee):

Ee \u003d Ez - Eza (3)

solar heat exchange on earth

Effective radiation is the net loss of radiant energy, and hence heat, from the earth's surface. This heat escaping into space is 1.60 GJ / (m2 * year), or 15% of the solar radiation that arrived at the upper boundary of the atmosphere (arrow E3 in Fig. 9.1). In temperate latitudes, the earth's surface loses through effective radiation about half of the amount of heat that it receives from absorbed radiation.

The radiation of the atmosphere is more complex than the radiation of the earth's surface. First, according to Kirchhoff's law, energy is emitted only by those gases that absorb it, i.e. water vapor, carbon dioxide and ozone. Secondly, the radiation of each of these gases has a complex selective character. Since the content of water vapor decreases with height, the most strongly radiating layers of the atmosphere lie at altitudes of 6-10 km. Long-wave radiation of the atmosphere into the world space Еa=5.54 GJ/(m2*year), which is 52% of the influx of solar radiation to the upper boundary of the atmosphere. The long-wave radiation of the earth's surface and the atmosphere entering space is called the outgoing radiation EU. In total, it is equal to 7.14 GJ/(m2*year), or 67% of the influx of solar radiation.

Substituting the found values ​​of So, Soa, Sop, Ee and Ea into equation (1), we get - ?Sz = 0, i.e., the outgoing radiation, together with the reflected and scattered short-wave radiation Soz, compensate for the influx of solar radiation to the Earth. In other words, the Earth, together with the atmosphere, loses as much radiation as it receives, and, therefore, is in a state of radiative equilibrium.

The thermal equilibrium of the Earth is confirmed by long-term observations of temperature: the average temperature of the Earth varies little from year to year, and remains almost unchanged from one long-term period to another.

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 the 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 fluxes 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 meteorological satellites of the Earth) 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 surface of the Earth 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═══════Р═════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 source of heat and light energy for the Earth is solar radiation. Its value depends on the latitude of the place, since the angle of incidence of the sun's rays decreases from the equator to the poles. The smaller the angle of incidence of the sun's rays, the large surface a beam of solar rays of the same cross section is distributed, and therefore there is less energy per unit area.

Due to the fact that during the year the Earth makes 1 revolution around the Sun, moving, maintaining a constant angle of inclination of its axis to the plane of the orbit (ecliptic), seasons of the year appear, characterized by different surface heating conditions.

On March 21 and September 23, the Sun is at its zenith under the equator (equinoxes). On June 22, the Sun is at its zenith over the Northern Tropic, on December 22 - over the Southern. Light zones and thermal zones are distinguished on the earth's surface (the border of the warm (hot) zone passes along the average annual isotherm + 20 ° C; between the average annual isotherms + 20 ° С and the isotherm + 10 ° С there is a temperate belt; according to the isotherm + 10 ° С - cold belt.

The sun's rays pass through the transparent atmosphere without heating it, they reach the earth's surface, heat it, and the air is heated from it due to long-wave radiation. The degree of heating of the surface, and hence the air, depends primarily on the latitude of the area, as well as on 1) height above sea level (as it rises, the air temperature decreases by an average of 0.6ºС per 100 m; 2) features of the underlying surface which can be different in color and have different albedo - the reflective ability of rocks. Also, different surfaces have different heat capacity and heat transfer. Water, due to its high heat capacity, heats up slowly and slowly, while land is vice versa. 3) from the coasts to the depths of the continents, the amount of water vapor in the air decreases, and the more transparent the atmosphere, the less sunlight is scattered in it by water drops, and more sunlight reaches the Earth's surface.

The totality of solar matter and energy entering the earth is called solar radiation. It is divided into direct and scattered. direct radiation- a set of direct sunlight penetrating the atmosphere with a cloudless sky. scattered radiation- part of the radiation scattered in the atmosphere, while the rays go in all directions. P + P = Total radiation. Part of the total radiation reflected from the Earth's surface is called reflected radiation. Part of the total radiation absorbed by the Earth's surface is absorbed radiation. Thermal energy moving from the heated atmosphere to the surface of the Earth, towards the flow of heat from the Earth is called the counter radiation of the atmosphere.

Annual amount of total solar radiation in kcal/cm 2 year (according to T.V. Vlasova).

Effective Radiation- a value expressing the actual transfer of heat from the Earth's surface to the atmosphere. The difference between the radiation of the Earth and the counter radiation of the atmosphere determines the heating of the surface. Radiation balance directly depends on effective radiation - the result of the interaction of two processes of arrival and consumption of solar radiation. The amount of balance is largely affected by cloudiness. Where it is significant at night, it intercepts the long-wave radiation of the Earth, preventing it from escaping into space.

The temperature of the underlying surface and surface layers of air and the heat balance directly depend on the influx of solar radiation.

The heat balance determines the temperature, its magnitude and change on the surface that is directly heated by the sun's rays. When heated, this surface transfers heat (in the long-wave range) both to the underlying layers and to the atmosphere. The surface itself is called the active surface.

The main components of the heat balance of the atmosphere and the surface of the Earth as a whole

Index	Value in %
Energy coming to the Earth's surface from the Sun
Radiation reflected by the atmosphere into interplanetary space, including 1) reflected by clouds 2) dissipates
Radiation absorbed by the atmosphere, including: 1) absorbed by clouds 2) absorbed by ozone 3) absorbed by water vapor
Radiation reaching the underlying surface (direct + diffuse)
From it: 1) is reflected by the underlying surface outside the atmosphere 2) is absorbed by the underlying surface.
From it: 1) effective radiation 2) turbulent heat exchange with the atmosphere 3) heat consumption for evaporation

In the diurnal course of surface temperature, dry and devoid of vegetation, on a clear day, the maximum occurs after 14:00, and the minimum occurs around the time of sunrise. Cloudiness, humidity and surface vegetation can disrupt the daily course of temperature.

Daytime maxima of land surface temperature can be +80 o C or more. Daily fluctuations reach 40 o. The values ​​of extreme values ​​and temperature amplitudes depend on the latitude of the place, season, cloudiness, thermal properties of the surface, its color, roughness, nature of the vegetation cover, slope orientation (exposure).

When heated, the surface transfers heat to the soil. Time is spent on the transfer of heat from layer to layer, and the moments of the onset of maximum and minimum temperature values ​​during the day are delayed by every 10 cm by about 3 hours. The deeper the layer, the less heat it receives and the weaker the temperature fluctuations in it. At an average depth of about 1 m, the daily fluctuations in soil temperature "fade out". The layer in which they stop is called the layer of constant daily temperature.

At a depth of 5-10 m in tropical latitudes and 25 m in high latitudes, there is a layer of constant annual temperature, where the temperature is close to the average annual air temperature above the surface.

Water heats up more slowly and releases heat more slowly. In addition, the sun's rays can penetrate to great depths, directly heating the deeper layers. The transfer of heat to depth is not so much due to molecular thermal conductivity, but to a greater extent due to the mixing of waters in a turbulent way or currents. When the surface layers of water cool, thermal convection occurs, which is also accompanied by mixing.

Unlike land, the diurnal temperature fluctuations on the surface of the ocean are less. In high latitudes, on average, only 0.1ºС, in temperate - 0.4ºС, in tropical - 0.5ºС. The penetration depth of these oscillations is 15-20 m.

Annual temperature amplitudes on the ocean surface from 1ºС in equatorial latitudes to 10.2ºС in temperate latitudes. Annual temperature fluctuations penetrate to a depth of 200-300 m.

The moments of temperature maxima in water bodies are delayed compared to land. The maximum occurs at about 15-16 hours, the minimum - 2-3 hours after sunrise. The annual maximum temperature on the surface of the ocean in the northern hemisphere occurs in August, the minimum - in February.

Radiation balance is the difference between the inflow and outflow of radiant energy absorbed and emitted by the Earth's surface.

Radiation balance - the algebraic sum of radiation fluxes in a certain volume or on a certain surface. Speaking about the radiation balance of the atmosphere or the "Earth - atmosphere" system, most often they mean the radiation balance of the earth's surface, which determines heat transfer at the lower boundary of the atmosphere. It represents the difference between the absorbed total solar radiation and the effective radiation of the earth's surface.

The radiation balance is the difference between the incoming and outgoing radiant energy absorbed and emitted by the Earth's surface.

The radiation balance is the most important climatic factor, since the distribution of temperature in the soil and the air layers adjacent to it largely depends on its value. Depend on him physical properties masses of air moving across the Earth, as well as the intensity of evaporation and melting of snow.

The distribution of annual values ​​of the radiation balance on the surface of the globe is not the same: in tropical latitudes, these values ​​reach up to 100 ... 120 kcal/(cm2-year), and the maximum (up to 140 kcal/(cm2-year)) are observed off the northwestern coast of Australia ). In desert and arid regions, the values ​​of the radiation balance are lower compared to areas of sufficient and excessive moisture at the same latitudes. This is caused by an increase in albedo and an increase in effective radiation due to the high dryness of the air and low cloudiness. In temperate latitudes, the values ​​of the radiation balance rapidly decrease with increasing latitude due to a decrease in total radiation.

On average, over the year, the sums of the radiation balance for the entire surface of the globe turn out to be positive, with the exception of areas with permanent ice cover (Antarctic, central part Greenland, etc.).

The energy, measured by the value of the radiation balance, is partly spent on evaporation, partly transferred to the air, and, finally, a certain amount of energy goes into the soil and goes to heat it. Thus, the total heat input-output for the Earth's surface, called the heat balance, can be represented as the following equation:

Here B is the radiation balance, M is the heat flux between the Earth's surface and the atmosphere, V is the heat consumption for evaporation (or heat release during condensation), T is the heat exchange between the soil surface and the deep layers.

Figure 16 - The impact of solar radiation on the Earth's surface

On average, over the year, the soil practically gives off as much heat to the air as it receives, therefore, in the annual conclusions, the heat turnover in the soil is zero. Heat consumption for evaporation is distributed on the surface of the globe very unevenly. On the oceans, they depend on the amount of solar energy reaching the surface of the ocean, as well as on the nature of ocean currents. Warm currents increase the consumption of heat for evaporation, while cold ones reduce it. On the continents, the cost of heat for evaporation is determined not only by the amount of solar radiation, but also by the reserves of moisture contained in the soil. With a lack of moisture, causing a reduction in evaporation, the heat costs for evaporation are reduced. Therefore, in deserts and semi-deserts, they are significantly reduced.

Practically the only source of energy for all physical processes developing in the atmosphere is solar radiation. The main feature of the radiation regime of the atmosphere is the so-called. greenhouse effect: the atmosphere weakly absorbs short-wave solar radiation (most of it reaches the earth's surface), but delays long-wave (entirely infrared) thermal radiation of the earth's surface, which significantly reduces the heat transfer of the Earth into outer space and increases its temperature.

The solar radiation entering the atmosphere is partially absorbed in the atmosphere, mainly by water vapor, carbon dioxide, ozone and aerosols, and is scattered by aerosol particles and fluctuations in the density of the atmosphere. Due to the scattering of the radiant energy of the Sun in the atmosphere, not only direct solar, but also scattered radiation is observed, together they constitute the total radiation. Reaching the earth's surface, the total radiation is partially reflected from it. The amount of reflected radiation is determined by the reflectivity of the underlying surface, the so-called. albedo. Due to the absorbed radiation, the earth's surface heats up and becomes a source of its own long-wave radiation directed towards the atmosphere. In turn, the atmosphere also emits long-wave radiation directed towards the earth's surface (the so-called counter-radiation of the atmosphere) and outer space (the so-called outgoing radiation). Rational heat exchange between the earth's surface and the atmosphere is determined by effective radiation - the difference between the Earth's own surface radiation and the atmosphere's counter-radiation absorbed by it. The difference between the shortwave radiation absorbed by the earth's surface and the effective radiation is called the radiation balance.

Transformations of the energy of solar radiation after its absorption on the earth's surface and in the atmosphere constitute the heat balance of the Earth. The main source of heat for the atmosphere is the earth's surface, which absorbs the bulk of solar radiation. Since the absorption of solar radiation in the atmosphere is less than the loss of heat from the atmosphere into the world space by long-wave radiation, the radiative heat consumption is compensated by the influx of heat to the atmosphere from the earth's surface in the form of turbulent heat transfer and the arrival of heat as a result of condensation of water vapor in the atmosphere. Since the total amount of condensation in the entire atmosphere is equal to the amount of precipitation, as well as the amount of evaporation from the earth's surface, the influx of condensation heat in the atmosphere is numerically equal to the heat spent on evaporation on the Earth's surface.