The radioactivity of the sun. Solar radiation or ionizing radiation from the sun

for example +79131234567

txt fb2 ePub html

What is it

Cheat sheets on the phone are an indispensable thing when passing exams, preparing for control works etc. Thanks to our service, you get the opportunity to download cheat sheets on meteorology and climatology to your phone. All cheat sheets are presented in popular formats fb2, txt, ePub, html, and there is also a java version of cheat sheets in the form of a convenient application for a mobile phone, which can be downloaded for a nominal fee. It is enough to download cheat sheets on meteorology and climatology - and you will not be afraid of any exam!

Community

Did not you find what you were looking for?

If you need an individual selection or work on an order - use it.

Next question "

The subject of meteorology and its main tasks.

Meteorology (from the Greek meteora - atmospheric phenomena and logos - word, doctrine), the science of the earth's atmosphere

Solar radiation. Distribution of solar radiation on the Earth's surface.

Electromagnetic radiation is a different form of matter from matter. A special case of radiation is visible light; but radiation also includes gamma rays, X-rays, ultraviolet and infrared radiation that are not perceived by the eye.

Radiation spreads in all directions from its source-emitter in the form of electromagnetic waves at the speed of light in a vacuum. Like any other wave, electromagnetic waves are characterized by their wavelength and frequency. All bodies with a temperature higher absolute zero emit radiation. Our planet receives radiation from the Sun; The earth's surface and atmosphere, at the same time, themselves emit thermal radiation, but in other wavelength ranges. If we consider the temperature conditions on the Earth for long periods of time, then we can accept the hypothesis that the Earth is in thermal equilibrium: the arrival of heat from the Sun is balanced by its loss into outer space.

Spectral composition solar radiation

In the spectrum of solar radiation, the wavelength interval between 0.1 and 4 microns accounts for 99% of all solar radiation energy. Only 1% remains for radiation with shorter and longer wavelengths, up to X-rays and radio waves.

Visible light occupies a narrow range of wavelengths. However, this interval contains half of all solar radiant energy. Infrared radiation accounts for 44%, and ultraviolet - 9% of all radiant energy.

The distribution of energy in the spectrum of solar radiation before it enters the atmosphere is now well known thanks to measurements from satellites. It is close enough to the theoretically obtained energy distribution in the blackbody spectrum at a temperature of about 6000 K.

Some substances in a special state emit radiation in greater quantities and in a different wavelength range,

than it is determined by their temperature. It is possible, for example, the emission of visible light at such low temperatures, at

which the substance usually does not glow. This radiation, which does not obey the laws of thermal radiation, is called luminescent.

Luminescence can occur if a substance has previously absorbed a certain amount of energy and entered the so-called excited state, which is richer in energy than the energy state at the temperature of the substance. With the reverse transition of matter - from an excited state to a normal state - and luminescence occurs. Luminescence explains the auroras and the glow of the night sky.

The radiant energy of the Sun is practically the only source of heat for the surface of the Earth and its atmosphere. The heat flux from the depths of the Earth to the surface is 5000 times less than the heat received from the Sun.

Some of the solar radiation is visible light. Thus, the Sun is a source of not only heat for the Earth, but also light, which is important for life on our planet.

The radiant energy of the Sun turns into heat partly in the atmosphere itself, but mainly on earth surface, where it goes to heating the upper layers of soil and water, and from them and air. The heated earth's surface and heated atmosphere, in turn, emit invisible infrared radiation. Giving radiation to the world space, the earth's surface and atmosphere are cooled.

Direct solar radiation

Radiation arriving at the earth's surface directly from the sun's disk is called direct solar radiation. Solar radiation spreads from the Sun in all directions. But the distance from the Earth to the Sun is so great that direct radiation falls on any surface on Earth in the form of a beam of parallel rays emanating from infinity, as it were. It is easy to understand that the maximum possible amount of radiation under these conditions is received by a unit of area located perpendicular to the sun's rays.

Solar constant

The quantitative measure of solar radiation arriving at a certain surface is the irradiance, or the density of the radiation flux, i.e. the amount of radiant energy incident on a unit of area per unit of time. The irradiance is measured in W / m2. As you know, the Earth revolves around the Sun along a slightly stretched ellipse, in one of the focuses of which is the Sun. In early January, the Earth is closest to the Sun (147-106 km), in early July - the farthest from it (152-106 km). Energy illumination changes in inverse proportion to the square of the distance,

Unscattered and unabsorbed in the atmosphere, direct solar radiation reaches the earth's surface. A small fraction of it is reflected from it, and most of the radiation is absorbed by the earth's surface, as a result of which the earth's surface heats up. Part of the scattered radiation also reaches the earth's surface, is partly reflected from it and partly absorbed by it. Another part of the scattered radiation goes upward into interplanetary space.

As a result of absorption and scattering of radiation in the atmosphere, the direct radiation that reached the earth's surface differs from that that came to the border of the atmosphere. The magnitude of the solar radiation flux decreases, and its spectral composition changes, since rays of different wavelengths are absorbed and scattered in the atmosphere in different ways

The atmosphere absorbs about 23% of direct solar radiation. Moreover, this absorption is selective: different gases absorb radiation in different parts of the spectrum and to varying degrees.

On the upper boundary of the atmosphere, solar radiation comes in the form of direct radiation. About 30% of direct solar radiation falling on Earth is reflected back into space. The remaining 70% is released into the atmosphere.

About 26% of the energy of the total solar radiation flux is converted into scattered radiation in the atmosphere. Near

2/3 of the scattered radiation then comes to the earth's surface.

But this will already be a special type of radiation, significantly different from direct radiation. First, scattered radiation comes

to the earth's surface not from the solar disk, but from the entire firmament.

Secondly, the scattered radiation differs from the straight line in the spectral composition, since the rays of different wavelengths are scattered to different degrees.

The scattering laws turn out to be significantly different depending on the ratio of the solar radiation wavelength and the size of the scattering particles.

Ozone is a strong absorber of solar radiation. It absorbs ultraviolet and visible solar radiation. Despite the fact that its content in the air is very small, it absorbs ultraviolet radiation so strongly in the upper atmosphere that waves shorter than 0.29 microns are not observed in the solar spectrum near the earth's surface.

Carbon dioxide (carbon dioxide) strongly absorbs radiation in the infrared region of the spectrum, but its content in the atmosphere is still small, therefore, its absorption of direct solar radiation is generally low.

Direct solar radiation on its way through the atmosphere is attenuated not only by absorption, but also by scattering, and is attenuated more significantly. Scattering is fundamental physical phenomenon interaction of light with matter. It can occur at all wavelengths of the electromagnetic spectrum, depending on the ratio of the size of the scattering particles to the wavelength of the incident radiation. During scattering, a particle located in the path of propagation of an electromagnetic wave continuously "extracts" energy from the incident wave and re-radiates it in all directions. Thus, the particle can be considered as a point source of scattered energy. Sunlight coming from the disk of the Sun, passing through the atmosphere, changes its color due to scattering. The scattering of solar radiation in the atmosphere is of great practical importance, as it creates scattered light in the daytime. In the absence of an atmosphere on Earth, there would be

light only where direct sunlight or sunlight reflected by the earth's surface and objects on it would fall. Due to the diffused light, the entire atmosphere during the day serves as a source of illumination: during the day it is also light where the sun's rays do not directly fall, and even when

the sun is hidden by clouds.

The blue color of the sky is the color of the air itself, due to the scattering of sunlight in it.

Turbidity factor

All attenuation of radiation by absorption and scattering can be divided into two parts: attenuation by constant gases (ideal atmosphere) and attenuation by water vapor and aerosol impurities. In summer, dusting increases, and the content of water vapor in the atmosphere also increases, which somewhat reduces radiation.

Total radiation

All solar radiation coming to the earth's surface - direct and scattered - is called total radiation

Cloudy reduces the total radiation. Therefore, in summer, the arrival of total radiation in the pre-noon hours is on average greater than in the afternoon. For the same reason, it is higher in the first half of the year than in the second.

Reflection of solar radiation. absorbed radiation. albedo of the earth

Falling on the earth's surface, the total radiation is mostly absorbed in the upper thin layer of the soil or in a thicker layer of water and turns into heat, and is partially reflected. The magnitude of the reflection of solar radiation by the earth's surface depends on the nature of this surface. The ratio of the amount of reflected radiation to the total amount of radiation falling on a given surface is called the surface albedo. This ratio is expressed as a percentage.

Radiation from the earth's surface

The upper layers of soil and water, snow cover and vegetation themselves emit long-wave radiation; this terrestrial radiation more often referred to as the intrinsic radiation of the earth's surface.

Radiation balance of the earth's surface

The difference between absorbed radiation and effective radiation is called the radiation balance of the earth's surface.

at night hours, when there is no total radiation, the negative radiation balance is equal to the effective radiation.

Effective radiation

The counter radiation is always slightly less than the terrestrial one. Therefore, the earth's surface loses heat due to the positive difference between its own and counterpropagating radiation. The difference between the intrinsic radiation of the earth's surface and the oncoming radiation of the atmosphere is called effective radiation. Effective radiation is a net loss of radiant energy, and hence heat from the earth's surface at night.

Effective radiation, of course, also exists during daylight hours. But during the day, it is blocked or partially compensated by absorbed solar radiation. Therefore, the earth's surface is warmer during the day than at night, but the effective radiation is also greater during the day.

Geographic distribution of total radiation

The distribution of annual and monthly amounts of total solar radiation over the globe is zonal: isolines (i.e., lines of equal values) of the radiation flux on the maps do not coincide with latitudinal circles. These deviations are explained by the fact that the transparency of the atmosphere and cloudiness affect the distribution of radiation over the globe.

Annual amounts of total radiation are especially high in low-cloud subtropical deserts. But over the equatorial forest areas with their large clouds, they are reduced. To higher latitudes in both hemispheres annual quantities total radiation decreases. But then they grow again - little in the Northern Hemisphere, but very significantly above the cloudy and snowy Antarctica. Over the oceans, the amount of radiation is lower than over land.

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. This means that the annual inflow 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 from year to year. The excess of absorbed radiation over radiation is balanced by the transfer of heat from the earth's surface to the air by means of 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 radiation equilibrium in the reception and release of radiation, but there is a thermal equilibrium: the flow of heat to the earth's surface by both radiation and non-radiation ways is equal to its return by the same methods.

The radiation balance on the oceans is greater than on land at the same latitudes. This is due to the fact that radiation in the oceans is absorbed by a larger layer than on land, and the effective radiation is not so large due to the lower temperature of the sea surface than the land surface. Significant deviations from the zonal distribution are found in deserts, where the balance is lower due to the large effective radiation in dry and slightly cloudy air. The balance is also lowered, but to a lesser extent in areas with monsoon climate, where in the warm season the cloudiness increases and the absorbed radiation decreases in comparison with other regions at the same latitude.

Geographic distribution of radiation balance

As is known, the radiation balance is the difference between the total radiation and the effective radiation. The effective radiation of the earth's surface is distributed over the globe more evenly than the total radiation. The fact is that with an increase in the temperature of the earth's surface, that is, with the transition to lower latitudes, the intrinsic radiation of the earth's surface increases; however, at the same time, the counter radiation of the atmosphere also grows due to the higher moisture content of the air and its higher temperature. Therefore, the changes in effective radiation with latitude are not too large.

Sunny radiation. Distribution solar radiation on the surface Of the earth.
In the spectrum solar radiation on the the wavelength interval between 0.1 and 4 microns accounts for 99% of all energy sunny radiation.

Radiation heat balance for surface Of the earth: Sunny radiation comes to surface Of the earth not
It is an important meteorological factor because its magnitude depends to a large extent distribution from t in the soil and adjacent air layers.

The main climate-forming factors. Sunny radiation and general circulation. Geographic latitude.
and annual rate radiation, temperature, precipitation and other quantities, their variability at each point Of the earth, the average distribution on earthly surface
Sunny radiation. Distribution solar radiation on the surface Of the earth.
The wind causes waves of water surfaces, many ocean currents, ice drift; it is an important factor in erosion and relief formation.

Sunny radiation radiation Suns.
Sunny radiation. Distribution solar radiation on the surface Of the earth.

Sunny radiation: it is electromagnetic and corpuscular radiation Suns.
Sunny radiation. Distribution solar radiation on the surface Of the earth.

Sunny radiation: it is electromagnetic and corpuscular radiation Suns.
Sunny radiation. Distribution solar radiation on the surface Of the earth.

Air flow in the atmosphere causes uneven distribution sunny warmth on the surface
The absolute humidity of the air appears; birds fly low over land because
The main climatic factors will be: * sunny radiation*circulation...

Similar pages found: 10

Introduction

The concept of solar radiation

1 Types of solar radiation

2 Methods for measuring radiation

Solar radiation intensity and its distribution

Solar radiation change

1 Absorption of solar radiation in the atmosphere

3.2 Scattering of solar radiation in the atmosphere

3 Phenomena associated with radiation scattering

Solar radiation near the earth's surface

1 Influence of solar radiation on plant and animal world

2 Human use of solar radiation

Seasonal changes in solar radiation

Conclusion

Introduction

Hundreds of books have been written about the sun and its energy. Physicists and chemists, astronomers and astrophysicists, geographers and geologists, biologists and engineers write about it. And this is not surprising, because the Sun is the main source of energy on our planet, setting in motion the entire mechanism of meteorological and climate-forming processes.

The energy of the Sun, which is mainly released in the form of radiant energy, is so great that it is difficult even to imagine it. Suffice it to say that only one two-billionth part of this energy comes to the Earth, but it is about 2.5 × 1018 cal / min. In comparison with this, all other sources of energy, both external (radiation from the moon, stars, cosmic rays) and internal (internal heat of the Earth, radioactive radiation, reserves coal, oil, etc.) are negligible.

The sun - the closest star to us, which is a huge luminous ball of gas, the diameter of which is about 109 times the diameter of the Earth, and its volume is about 1 million 300 thousand times the volume of the Earth. The Sun's average density is about 0.25 times that of our planet.

The temperature at the surface of the Sun is about 6000 O K. At such a high temperature, iron and other metals do not just melt, but turn into hot gases. Therefore, there are neither solid nor liquid substances on the Sun: there is only hot gas. The sun - it is a huge incandescent gas sphere, therefore, it is necessary to speak about its size conditionally, meaning by them the dimensions of the solar disk visible from the Earth.

The inner part of the sun is not visible. It is a kind of atomic boiler of gigantic dimensions, where the temperature reaches 15 billion degrees. This high temperature inside the Sun has existed for several billion years and will continue to exist for about the same. What is happening inside the sun? Why doesn't this giant fire go out? Astronomers and physicists have pondered the question for a long time: how, for billions of years, a very high temperature inside the Sun is maintained? Most scientists believe that inside the sun chemical element hydrogen turns into another chemical element, helium. Particles of hydrogen combine into heavier particles, with this combination, energy is released in the form of light and heat, which is scattered by the Sun in outer space and comes to Earth to give life to all living things.

Objective: to study the effect of solar radiation on geographic envelope Earth.

Tasks:) find out what solar radiation is;

b) describe the types of radiation;

c) study how solar radiation affects flora and fauna;

d) give examples of the use of solar energy;

e) analyze the seasonal change in solar radiation on the earth's surface.

1. The concept of solar radiation

The energy emitted by the sun is called solar radiation. When entering the Earth, most of the solar radiation turns into heat.

Solar radiation is practically the only source of energy for the Earth and the atmosphere. Compared to solar energy, the value of other energy sources for the Earth is negligible. For example, the temperature of the Earth, on average, increases with depth (approximately 1 O C for every 35 m). Due to this, the surface of the Earth receives some heat from the interior. It is estimated that on average 1cm 2the earth's surface receives from the inner parts of the earth about 220 J per year. This amount is 5,000 times less than the heat received from the Sun. The Earth receives a certain amount of heat from stars and planets, but it is also many times (approximately 30 million) less than the heat coming from the Sun.

The amount of energy sent by the Sun to Earth is enormous. Thus, the power of the solar radiation flux entering an area of 10 km 2,is cloudless in summer (taking into account the weakening of the atmosphere) 7 - 9 kW. This is more than the capacity of the Krasnoyarsk hydroelectric power station. The amount of radiant energy coming from the Sun in 1 second per area 15 × 15 km (this is less than the area of Leningrad) in the midday hours in summer, exceeds the capacity of all power plants of the disintegrated USSR (166 million kW).

Figure 1 - The sun is a source of radiation

.1 Types of solar radiation

In the atmosphere, solar radiation on its way to the earth's surface is partially absorbed, and partially scattered and reflected from clouds and the earth's surface. Three types of solar radiation are observed in the atmosphere: direct, scattered and total.

Direct solar radiation -radiation coming to the earth's surface directly from the solar disk. Solar radiation spreads from the Sun in all directions. But the distance from the Earth to the Sun is so great that direct radiation falls on any surface on Earth in the form of a beam of parallel rays emanating from infinity, as it were. Even the entire globe as a whole is so small in comparison with the distance to the Sun that all solar radiation falling on it, without a noticeable error, can be considered a beam of parallel rays.

Only direct radiation reaches the upper boundary of the atmosphere. About 30% of the radiation falling on the Earth is reflected into outer space. Oxygen, nitrogen, ozone, carbon dioxide, water vapor (clouds) and aerosol particles absorb 23% of direct solar radiation in the atmosphere. Ozone absorbs ultraviolet and visible radiation. Despite the fact that its content in the air is very small, it absorbs all the ultraviolet part of the radiation (this is about 3%). Thus, it is not observed at all near the earth's surface, which is very important for life on Earth.

Direct solar radiation is also scattered on its way through the atmosphere. A particle (drop, crystal or molecule) of air, located in the path of an electromagnetic wave, continuously "extracts" energy from the incident wave and re-radiates it in all directions, becoming an energy emitter.

About 25% of the energy of the total flow of solar radiation passing through the atmosphere is scattered by molecules of atmospheric gases and aerosol and turns into scattered solar radiation in the atmosphere. In this way diffuse solar radiation-solar radiation scattered in the atmosphere. Scattered radiation comes to the earth's surface not from the solar disk, but from the entire firmament. Scattered radiation differs from a straight line in spectral composition, since beams of different wavelengths are scattered to different degrees.

Since the primary source of scattered radiation is direct solar radiation, the scattered radiation flux depends on the same factors that affect the direct radiation flux. In particular, the flux of scattered radiation increases as the height of the Sun increases and vice versa. It also increases with an increase in the number of scattering particles in the atmosphere, i.e. with a decrease in the transparency of the atmosphere, and decreases with altitude above sea level due to a decrease in the amount of scattering particles in the overlying layers of the atmosphere. Cloudiness and snow cover have a very large effect on scattered radiation, which, due to the scattering and reflection of direct and scattered radiation falling on them and their repeated scattering in the atmosphere, can increase the scattered solar radiation several times.

Scattered radiation substantially complements direct solar radiation and significantly increases the flow of solar energy to the earth's surface. Its role is especially great in winter at high latitudes and in other regions with increased cloudiness, where the fraction of scattered radiation can exceed the fraction of a straight line. For example, in the annual amount of solar energy, scattered radiation accounts for 56% in Arkhangelsk, and 51% in St. Petersburg.

Total solar radiation -it is the sum of the fluxes of direct and scattered radiation arriving at the horizontal surface. Before sunrise and after sunset, as well as in the daytime with continuous clouds, the total radiation is completely, and at low altitudes of the Sun it mainly consists of scattered radiation. In a cloudless or slightly cloudy sky, with an increase in the height of the Sun, the proportion of direct radiation in the total composition rapidly increases and in daytime its flux is many times greater than the flux of scattered radiation. Cloudiness, on average, weakens the total radiation (by 20 - 30%), however, with partial clouds that do not cover the solar disk, its flux may be greater than with a cloudless sky. Snow cover significantly increases the total radiation flux by increasing the scattered radiation flux.

The total radiation falling on the earth's surface is mostly absorbed by the top layer of the soil or by a thicker layer of water (absorbed radiation) and turns into heat, and is partially reflected (reflected radiation).

1.2 Methods for measuring radiation

solar radiation atmosphere animal

For the measurement of direct and scattered solar radiation, radiation balance and other types of radiation, there are many devices with both visual reports and automatic registration. We will restrict ourselves to considering the general principles of their construction.

Devices for measuring direct solar radiation are called pyrheliometers and actinometers, for measuring scattered radiation - pyranometers for measuring the radiation balance - balancers.

To measure radiation, a blackened metal plate is used, which by its absorbing properties is almost identical to an absolute black body, i.e. absorbs and turns into heat all radiation falling on it. In addition, many devices include plates with a white surface, which almost completely reflect the incident radiation.

In Angstrom's compensation pyrheliometer, a blackened metal plate is exposed to the Sun, while another similar plate remains in the shadow. A temperature difference arises between the plates. This temperature difference is transferred to the thermoelement junctions glued (with insulation) to the plates, and thereby excites the thermoelectric current. A current from the battery is passed through the darkened plate until the plate heats up to the same temperature to which the first plate was heated by the sun's rays; then the thermoelectric current disappears. By the strength of the passed "compensating" current, it is possible to determine with the help of Joule-Lenz the amount of heat received from the Sun by the first plate. From here, you can determine the amount of solar radiation. There are other types of pyrheliometers.

In a Savinov-Yanishevsky thermoelectric actinometer, the receiving part is a thin blackened metal disc. Odd thermopile junctions are glued to it through insulation. The even junctions of the thermopile are also glued through insulation to the copper ring in the device case. Under the influence of solar radiation, an electric current arises, by the strength of which the intensity of radiation is determined. This requires a conversion factor of the device, which is determined by comparison with an absolute device-pyrheliometer.

In a pyranometer, the receiving part is most often a battery of thermoelements, for example, made of manganin and constantan with blackened and white junctions. The receiving part of the device must have a horizontal position in order to perceive scattered radiation from the entire sky. It is shaded from direct solar radiation by a screen, and from the oncoming radiation of the atmosphere it is protected by a glass cover. Under the influence of scattered radiation, the black and white junctions are heated unequally, and a thermoelectric current arises, according to the strength of which the value of radiation is determined (the conversion factor of the device is set in advance). When measuring total radiation, the pyranometer is not shaded from direct sunlight.

The radiation balance is determined by a thermoelectric balance meter, in which one blackened receiving plate is directed upwards, and the other - down to the earth's surface. The difference in the heating of the plates makes it possible to determine the value of the radiation balance. At night it is equal to the amount of effective radiation.

For automatic registration of measurements, the thermoelectric current arising in the actinometer, pyranometer, balance meter is fed to a recording electronic potentiometer. Changes in amperage are recorded on a moving paper tape. In this case, the actinometer should automatically rotate so that its receiving part follows the Sun, and the pyranometer should always be shaded from direct radiation by a special ring shield.

Pyrheliometer; 2 - actinometer; 3 - pyranometer

Figure 2 - Instruments for measuring solar radiation

Thus, using methods of measuring solar radiation, we can determine many indicators, because the intensity of solar radiation, reflected radiation, the amount of effective radiation, components of the heat balance, etc.

2. The intensity of solar radiation and its distribution

The intensity of solar radiation before it enters the atmosphere (usually they say: "at the upper boundary of the atmosphere" or "in the absence of an atmosphere") is called the solar constant. The meaning of the word constant is that this value does not depend on the absorption and scattering of radiation in the atmosphere. It refers to radiation that has not yet been influenced by the atmosphere. The solar constant therefore depends only on the emissivity of the sun and on the distance between the earth and the sun.

The Earth revolves around the Sun along a slightly stretched ellipse, in one of the focuses of which is the Sun. In early January, it is closest to the Sun (147 million km), in early July, it is farthest from it (152 million km). Since the intensity of radiation changes in inverse proportion to the square of the distance, the solar constant changes by ± 3.5% throughout the year. With the Earth's average distance from the Sun, the solar constant, according to the latest definitions using rocket measurements, is 2.00 ± 0.04 cal / cm 2 min. However, according to international agreement, its standard value is 1.98 cal / cm 2min. Solar radiation intensity of 2 cal / cm 2in 1 minute gives such a large amount of heat throughout the year that it would be enough to melt a layer of ice 35 meters thick, if such a layer covered the entire earth's surface.

Does the solar constant change, and how significantly, over time, regardless of the change in the distance between the Sun and the Earth? In other words, does the sun's radiation change over time? Undoubtedly, during the existence of the Sun, the solar constant must have changed. A more controversial issue is whether it has changed significantly throughout the geological history of the Earth. Finally, it is not yet known whether the solar constant fluctuates, and by how much, from day to day and from year to year. However, if such fluctuations exist, then they are so small that they lie within the accuracy of determining the solar constant.

3. Change in solar radiation

Passing through the atmosphere, solar radiation is partially scattered by atmospheric gases and aerosol impurities to the air and turns into a special form of scattered radiation. It is partially absorbed by molecules of atmospheric gases and impurities in the air and turns into heat, goes to heating the atmosphere.

Unscattered and unabsorbed in the atmosphere, direct solar radiation reaches the earth's surface. It is partially reflected from the earth's surface, but to a greater extent is absorbed by it and heats it up. Part of the scattered radiation also reaches the earth's surface, is partly reflected from it and partly absorbed by it. Another part of the scattered radiation goes upward into interplanetary space.

As a result of absorption and scattering of radiation in the atmosphere, the direct radiation that reached the earth's surface is changed in comparison with what was at the border of the atmosphere. The intensity of radiation decreases, and its spectral composition changes, since rays of different wavelengths are absorbed and scattered in the atmosphere in different ways.

The atmosphere absorbs about 23% of direct solar radiation. Moreover, this absorption is selective: different gases absorb radiation in different parts of the spectrum and to varying degrees. The main absorber of radiation in the short-wavelength region of the spectrum is nitrogen and ozone, in the long-wavelength region - water vapor and carbon dioxide.

Nitrogen absorbs radiation only at very short wavelengths in the ultraviolet part of the spectrum. The energy of solar radiation in this part of the spectrum is absolutely negligible, therefore, absorption by nitrogen practically does not affect the flow of solar radiation. To a somewhat greater extent, but still very little, oxygen absorbs solar radiation in two narrow regions of the visible part of the spectrum and in its ultraviolet part.

A stronger absorber of solar radiation is ozone. Despite its very low content in the atmosphere, it completely absorbs solar radiation with a wavelength of less than 0.29 microns, as a result of which such waves are not observed in the spectrum of solar radiation near the earth's surface. Ultraviolet waves, especially the shortest ones, are biologically very active and in excess quantities have a harmful or even destructive effect on living organisms. The atmospheric ozone layer is a kind of protective shield, a "biological shield" that protects life on Earth. The absorption of part of the ultraviolet radiation of the Sun by stratospheric ozone explains the temperature distribution with height characteristic of the stratosphere and the relatively high air temperatures in this layer.

In addition to ultraviolet radiation, ozone absorbs, albeit much weaker, radiation of certain wavelengths in the visible and infrared regions of the spectrum. The total absorption of solar radiation by ozone reaches 3% of direct solar radiation.

In the long-wavelength region of the spectrum, water vapor absorbs the largest proportion of radiation. Carbon dioxide is also a strong absorber of infrared radiation, but due to its low content in the atmosphere, the total amount of radiation absorbed by it is small.

A significant amount of both short-wave and long-wave radiation is absorbed by clouds and various atmospheric aerosols, especially when the atmosphere is highly turbid (in cities, during strong forest and peat fires, etc.)

In general, absorption by water vapor and aerosol absorption account for about 15%, the remaining 5% are absorbed by clouds.

At each separate location, the absorption changes over time, depending both on the variable content of absorbing substances in the air, mainly water vapor, clouds and dust, and on the height of the Sun above the horizon, i.e. on the thickness of the layer of air passed by the rays on the way to the Earth.

.2 Scattering of solar radiation in the atmosphere

Direct solar radiation on its way through the atmosphere is attenuated not only by absorption, but also by scattering, and is attenuated more significantly. Scattering - it is a fundamental physical phenomenon of the interaction of light with matter. It can occur at all wavelengths of the electromagnetic spectrum, depending on the ratio of the size of the scattering particles to the wavelength of the incident radiation. During scattering, a particle located in the path of distribution of an electromagnetic wave continuously "extracts" energy from the incident wave and re-radiates it in all directions. Thus, the particle can be considered as a point source of scattered energy. Consequently, scattering is the transformation of a particle of direct solar radiation, which, before scattering, propagates in the form of parallel rays in a certain direction, into radiation going in all directions. Scattering occurs in optically inhomogeneous atmospheric air containing the smallest particles of liquid and solid impurities - drops, crystals, tiny aerosols, i.e. in an environment where the refractive index changes from point to point. But clean air, free of impurities, is also an optically inhomogeneous medium, since in it, due to the thermal movement of molecules, condensations and rarefaction, density fluctuations constantly occur. Meeting with molecules and impurities in the atmosphere, the sun's rays lose their rectilinear direction of propagation and scatter. Radiation spreads from scattering particles in such a way as if they were emitters themselves.

Thus, about 26% of the energy of the total solar radiation flux is converted into scattered radiation in the atmosphere. About 2/3 of the scattered radiation then comes to the earth's surface.

.3 Phenomena related to radiation scattering

One of the primitive examples of radiation scattering that we see almost every day is the blue color of the sky. Blue sky - it is the color of the air itself, due to the scattering of the sun's rays in it. Air is transparent in a thin layer, as water is transparent in a thin layer. But in a powerful layer of the atmosphere, the air is blue, just like water is already in a relatively small layer

(several meters) is green. Since molecular scattering of light is inversely proportional, then in the spectrum of scattered light sent by the firmament, the maximum energy is shifted to blue. Thus, the firmament is blue. The blue color of air can be seen not only by looking at the firmament, but also by examining individual objects that seem to be shrouded in a bluish haze. With height, as the air density decreases, i.e. the amount of scattering particles, the color of the sky becomes darker and turns into a deep blue, and in the atmosphere - in black and purple. According to the testimony of astronauts, at an altitude of 300 km, the sky is black. The increase in the proportion of scattered violet rays with height is clearly visible in the mountains, which appear blue-violet in clean air.

The more impurities in the air of a larger size than air molecules, the greater the proportion of long-wavelength rays in the spectrum of solar radiation and the whitish the color of the firmament becomes. When the particle diameter of fog, clouds and aerosols becomes more than 1 - 2 microns, then the rays of all wavelengths are no longer scattered, but are equally diffusely reflected; therefore, in the fog and dusty haze, individual objects are no longer covered with blue, but with a white or gray curtain. Therefore, the clouds on which the sunlight (i.e. white) light falls, appear white.

Figure 3 - Blue color of the sky

Sunlight coming from the disk of the Sun, passing through the atmosphere, changes its color due to scattering. Scattering reduces the energy of the shortest wavelengths in the visible spectrum the most. - blue and violet, therefore, direct sunlight "escaped" from scattering becomes yellowish. The solar disk appears to be the more yellow the closer it is to the horizon, i.e. the longer the path of the rays through the atmosphere and, therefore, the greater the scattering. Near the horizon, the Sun turns almost red, especially when there is a lot of dust and the smallest condensation products (drops or crystals) in the air. In the same way, sunlight reflected by clouds, scattered on the way to the earth's surface, becomes poorer in blue rays. Therefore, when the clouds are close to the horizon and the path of the rays of light reflected from them, passing through the atmosphere to the observer, is great, they acquire a yellowish color instead of white.

Figure 4 - Yellowish color of clouds

The scattering of solar radiation in the atmosphere is of great practical importance, as it creates scattered light in the daytime. In the absence of an atmosphere on Earth, it would be bright only where direct sunlight or sunlight reflected by the earth's surface and objects on it would fall. Due to the scattered light, the entire atmosphere during the day serves as a source of illumination: during the day it is also light where the sun's rays do not directly fall, and even when the Sun is hidden by clouds.

Figure 5 - Scattered light in the daytime

4. Solar radiation near the earth's surface

As we already know, direct solar radiation, when passing through the atmosphere, reaches the earth's surface, weakened by atmospheric absorption and scattering. In addition, there are always clouds in the atmosphere, and direct solar radiation often does not reach the earth's surface at all, being absorbed, scattered and reflected back by the clouds. Cloudiness can reduce the flow of direct radiation over a wide range. For example, in Tashkent in low-cloud August, only 20% of direct solar radiation is lost due to the presence of clouds, and in Vladivostok, with its monsoon climate, the loss of direct radiation due to cloudiness in summer is 75%. In St. Petersburg, even on average per year, clouds do not transmit 65% of direct radiation to the earth's surface.

Table 1 - Average influx of solar radiation in the Northern Hemisphere on a horizontal surface on the days of equinoxes and solstices

Day Latitude, deg. 0 - 1010- 2020- 3030- 4040- 5050- 6060- 90 At the upper boundary of the atmosphere 21 / XII 21 / III 21 / VI 23 / IX 0.383 0.432 0.404 0.4250.324 0.420 0.440 0.3920.260 0.386 0.463 0.3880.191 0.355 0.477 0.3510.121 0.308 0.481 0.3040 .055 0.250 0.477 0.2460.004 0.147 0.491 0.145 Direct radiation at the earth's surface 21 / XII 21 / III 21 / VI 23 / IX 0.114 0.133 0.101 0.1190.112 0.156 0.118 0.11130.094 0.144 0.151 0.1400, 057 0.112 0.163 0.1280.025 0.081 0.128 0.0910.009 0.068 0.111 0.0550.001 0.038 0.093 0.019 Scattered radiation at the earth's surface 21 / XII 21 / III 21 / VI 23 / IX 0.045 0.075 0.073 0.0750.055 0.073 0.079 0.0720.046 0.069 0.0865 0.0680.036 0.065 0.087 0.0640.024 0.058 0.088 0.0560.011 0.046 0.035 0.0450.001 0.033 0.107 0.034 From this table, we can conclude that the actual amounts of direct solar radiation reaching the earth's surface during a given time will be significantly less than the amounts calculated for the atmospheric boundary. Their distribution over the globe will be more complicated, since the degree of transparency of the atmosphere and cloud conditions are highly variable depending on the geographic setting.

However, upon reaching the earth's surface, most of the total radiation flux entering the earth's surface is absorbed by the top layer of soil, water, and vegetation; in this case, the radiant energy is converted into heat, heating the absorbing layers. The rest of the total radiation flux is reflected by the earth's surface, forming reflected radiation. Almost the entire flux of reflected radiation passes through the atmosphere and goes into world space, but some of it is scattered in the atmosphere and partially returns to the earth's surface, increasing the scattered radiation, and therefore the total.

The reflectivity of various surfaces is called albedo. It is the ratio of the reflected radiation flux to the total flux of total radiation incident on a given surface. Thus, the earth's surface reflects part of the total radiation flux, and part is absorbed and converted into heat.

The albedo of various land surfaces depends mainly on the color and roughness of those surfaces. Dark and rough surfaces have a lower albedo than light and smooth surfaces. The albedo of soils decreases with increasing moisture content, since their color becomes darker.

Table 1 - Albedo value for some natural surfaces

Surface Albedo, percent Surface Albedo, percent Fresh dry snow 80 - 95Luga15 - 25 Polluted snow 40 - 50 Fields of rye and wheat 10 - 25Dark Soils5 - 15Coniferous forests10 - 15 Dry sandy soils 25 - 45 Deciduous forests15 - 20

The albedo of water surfaces is, on average, less than the albedo of the land surface, and it is highly dependent on the height of the Sun. The smallest albedo is observed with a steep incidence of sunlight (2 - 5%), the smallest - at low solar heights (50 - 70%). In a similar way, but much weaker, it changes depending on the height of the Sun and the physical state of the albedo of other natural surfaces, and therefore, in the diurnal cycle, its greatest values are observed in the morning and in the evening, the largest - at noon hours.

The reflectivity of the upper surface of the clouds is very high, especially at their high power. On average, cloud albedo is about 50 - 60%, in some cases - more than 80 - 85 %.

In temperate and high latitudes, the albedo changes strongly in the annual course, since due to the formation of snow cover in winter it is much higher (50 - 80%) than in summer.

The ratio of the reflected and scattered radiation leaving into outer space to the entire flow of solar radiation entering the atmosphere is called the planetary albedo of the Earth. On average, it is about 30%, and most of it is due to the reflection of solar radiation by clouds.

4.1 Influence of solar radiation on flora and fauna

The sun has a significant impact not only on flora and fauna, but also on humans. Some people wake up and are awake only when the sun is shining (this also applies to most mammals, amphibians and even most fish). The length of a sunny day affects the life of organisms on Earth. In particular, in winter and autumn, when the Sun in the Northern Hemisphere is low above the horizon, and the duration of daylight hours is small and the amount of solar heat is low, nature withers and falls asleep - trees shed their leaves, many animals hibernate for a long time (bears, badgers) or greatly reduce their activity. Near the poles, even during the summer, there is little solar heat, because of this, the vegetation there is scarce - the reason for the dull tundra landscape, and few animals can live in such conditions. In the spring, all nature wakes up, the grass blooms, the trees release leaves, flowers appear, the animal world comes to life. And all this is due to one single sun. His climatic influence to Earth undeniably. It is thanks to the uneven flow of solar energy to different regions of the Earth and at different times of the year that climatic zones have formed on Earth.

Similarly, without the Sun, such a chemical process as photosynthesis could not take place. Green leaves of plants contain the green pigment chlorophyll - this pigment is the most important catalyst on Earth. With its help, the reaction of carbon dioxide and water takes place - photosynthesis, and one of the products of this reaction is oxygen - an element that is necessary for life for almost all life on Earth and globally influenced the evolution of our planet - in particular, the composition of minerals has radically changed. The reaction of water and carbon dioxide occurs with the absorption of energy, so photosynthesis does not occur in the dark. Photosynthesis, converting solar energy and producing oxygen, gave rise to all life on Earth. This reaction produces glucose, which is the most important raw material for the synthesis of cellulose, of which all plants are composed. By eating plants in which energy is accumulated due to the sun, animals also exist. Plants of the Earth absorb and assimilate only about 0.3% of the solar radiation energy falling on the earth's surface. But even this, at first glance, a meager amount of energy is enough to ensure the synthesis of a huge amount of mass of organic matter in the biosphere.

Thus, the Sun is the main source of life on Earth.

4.2 Human use of solar radiation

The question of the possibility of direct use of solar energy, which interested people in antiquity, in last years becomes more and more relevant. The problems of the technical use of solar radiation are dealt with by solar engineering, which is now receiving great attention all over the world. The energy of the Sun can be used for technical and domestic purposes: heating and lighting, water desalination, drying fruits and vegetables, etc. cloudless) days of the year.

The use of solar energy in modern practice is carried out by converting it into thermal and electrical energy.

The rapid decrease in the reserves of fossil fuels (coal, oil, gas) and the pollution of the natural environment during their combustion forces the search for more efficient sources of energy. Primarily - it is the energy of the sun. For us the sun - the nearest thermonuclear giant reactor, operating for billions of years. Only the Karakum Desert receives as much solar radiation per year as it contains 3.5 billion tons of oil. Having learned how to utilize at least 20% of this radiation, we could get from each site with an area of 4 - 5 thousand km 21300 billion kWh each.

The sun - not only inexhaustible, but also absolutely clean energy sources: it does not give any harmful emissions. There is no so-called thermal pollution that can "spoil" the microclimate of the area, overheat the biosphere on a global scale, which may be a consequence of the unlimited use of thermonuclear energy.

Currently, there are four directions in the use of solar energy: polytechnic, photovoltaic, biological and chemical.

First direction - it is the conversion of solar energy into thermal energy.

Second direction - conversion of solar energy into electrical energy using photocells - received wide application in astronautics (photovoltaic solar cells).

Third direction - development of biological systems.

Fourth direction - decomposition of water by sunlight into oxygen and hydrogen.

Figure 8 - Solar power plant uses solar radiation to generate electricity

In many industries National economy the radiation regime plays an important role. For scientific agriculture, it is necessary to know the actual amounts of radiation coming to the earth's surface during the growing season and in all other periods of the year. For this, one should take into account the nature of the active surface, the presence of slopes, hills, etc., since the amount of radiation absorbed by the soil depends on the angle of incidence of the rays and the albedo of the surface.

Solar radiation is widely used for medicinal purposes. Therefore, in balneology, for the correct choice of time and dose of irradiation of patients, it is necessary to know the daily and annual course of direct and scattered radiation, their sums and maximum values. To obtain this information, some resorts are equipped with special actinometric stations.

When designing cities, buildings should be positioned in such a way as to provide the most favorable illumination of the sun's rays. It is necessary to know the amount of radiation entering the vertical walls of various orientations. It should be borne in mind that they receive not only direct and scattered radiation, but also radiation reflected from the adjacent areas of the earth's surface and from other closely located buildings. The maximum amounts of solar radiation do not always fall on the summer months and on the southern walls. In particular, the arrival of direct radiation on the southern walls is observed throughout the year, but its maximum occurs in the spring. With increasing latitude, the annual amount of incoming radiation decreases.

The northern walls are irradiated from March to September, and the maximum is in June - July. During these months, with increasing latitude, the daily and monthly amounts of incoming radiation increase. The arrival of radiation on the eastern and western walls depends mainly on the diurnal and annual variations in cloud cover.

5. Seasonal changes in solar radiation

We already know how the solar constant changes throughout the year and, therefore, the amount of radiation coming to the Earth. If we determine the solar constant for the actual distance of the Earth from the Sun, then with an average annual value of 1.98 cal / cm 2min it will be equal to 2.05 cal / cm 2min in January and 1.91 cal / cm 2min in July.

Consequently, the northern hemisphere receives slightly less radiation at the border of the atmosphere during a summer day than Southern Hemisphere for your summer day.

The sphericity of the Earth and the inclination of the equatorial plane to the pole of the ecliptic (23.5 O ) creates a complex distribution of radiation flux across latitudes at the boundary of the atmosphere and its changes throughout the year.

Figure 9 - Inflow of solar radiation on a horizontal surface in the winter and summer semesters and for the whole year, depending on the geographical latitude

It can be seen from the figure that over the course of a year, the amount of incoming solar radiation varies from 318 kcal at the equator to 133 kcal at the pole.

In winter, the influx of radiation decreases very quickly from the equator to the pole, in summer - much slower. At the same time, the maximum in summer is observed in the tropics, and from the tropics to the equator, the inflow of radiation decreases somewhat.

The small difference in the inflow of radiation between tropical and polar latitudes in summer is explained by the fact that the heights of the Sun at polar latitudes in summer it is lower than in the tropics, but the length of the day is great. On the day of the summer solstice, the pole, therefore, would receive more radiation in the absence of an atmosphere than the equator. However, near the earth's surface, as a result of the attenuation of radiation by the atmosphere, its reflection by cloudiness, etc., the summer inflow of radiation at polar latitudes is significantly less than at lower latitudes.

Calculations show that on the upper boundary of the atmosphere outside the tropics, there is in the annual cycle one maximum of radiation, falling on the time of the summer solstice, and one minimum, falling on the time of the winter solstice. But between the tropics, the influx of radiation has two maximums per year, falling on those times when the Sun reaches its highest noon height. At the equator it will be at the equinoxes, in other intertropical latitudes - after the vernal and before the autumnal equinox, the greater the latitude, the more moving away from the equinox dates. The amplitude of the annual cycle at the equator is small, inside the tropics it is small; in temperate and high latitudes, it is much higher.

Conclusion

From all of the above, we can conclude that the Sun is the source of life for everything earthly. It plays a huge role in the course of chemical processes on Earth. The sun evaporates water from the oceans, seas, from the earth's surface. It turns this moisture into droplets of water, forming clouds and fogs, and then causes it to fall back to Earth as rain, snow, dew or frost, thus creating a gigantic cycle of moisture in the atmosphere.

Solar energy is the source of the general circulation of the atmosphere and the circulation of water in the oceans. It seems to create a gigantic system of water and air heating of our planet, redistributing heat over the earth's surface.

Sunlight, falling on a plant, causes the process of photosynthesis in it, determines the growth and development of plants; getting on the soil, it turns into heat, heats it, forms the soil climate, thereby giving vitality to the seeds of plants in the soil, microorganisms and living creatures inhabiting it, which without this heat would be in a state of suspended animation (hibernation).

Thus, we can conclude that the Sun - it is the main source of energy on Earth and, the root cause that created most of the other energy resources of our planet, such as reserves of coal, oil, gas, wind and falling water energy, electrical energy, etc.

List of sources used

1 Large information archive [Electronic resource] // Solar radiation as it appears to us. - 2010 .-- March 2. - URL: # "justify"> 2 Gontaruk T.I. I get to know the world: an encyclopedia. - M .: OOO "AST Publishing House", 2003. - 445 p.

3 Matveev L.T. General Meteorology Course. Physics of the atmosphere: a textbook for university students. - 2nd ed., Rev. and add. - L., 1994 - 751 p.

4 World theme- popular edition [Electronic resource] // The sun is a source of radiation. - 2015 .-- January 14. - URL:<#"justify">12 Kondratyev K.Ya., Binenko V.I., Melnikova V.I. Meteorology and hydrology: textbook. - M., 1996. -174 s.

13 Solar radiation [Electronic resource] / Blue color of the sky. - Moscow, 2015. - URL: # "justify"> 16 Guralnik I.I., Dubinsky G.P., Larin V.V., Mamikonova S.V. Meteorology. -2nd ed., Rev. - L .: Gidrometeoizdat, 1982 .-- 440 p.

Budyko M.I. Meteorology and hydrology: textbook. - M., 1998 .-- 129 p.

18 Biofile - Scientific and informational journal [Electronic resource] // Influence of the Sun on the planet Earth. - 2014 .-- April 4. - URL: http://biofile.ru/kosmos/4362.html (date of access: 3.03.2015).

Zakharovskaya N.N., Ilyinich V.V. Meteorology and climatology: study guides for students of higher. study. institutions. - M .: KolosS, 2005 .-- 127 p.

Regional Policy Information Agency [Electronic resource] / Solar power plant. - M, 2015. - URL: http://goo.gl/OqpsCs (date of treatment 03.25.2015).

Educational materials [Electronic resource] / Inflow of solar radiation. - 2015 .-- November 24. - URL: http://goo.gl/2iaXkt (date of treatment 03/27/2015).

Humanity and the environment

The lithosphere is the solid shell of the Earth, a source of mineral raw materials and fossil fuels, soil ...
The "thermal contribution" of human activity is in n. c. 0.006% of solar radiation. The consequence of this will be an increase in the temperature of the planet by 10C.

Atmospheric air protection

Both are envy of climatic conditions, different geographic areas of the earth.
... the dissociation of oxygen molecules under the influence of solar radiation in the upper atmosphere at an altitude of 10-50 km. His concentration also ...

Solar radiation and its impact on natural and economic processes

You can find out the cost of helping to write a student paper.

Help in writing a work that will definitely be accepted!

Introduction

Chapter 1. Theoretical aspects of solar radiation

1 Absorption and scattering of direct solar radiation in the atmosphere

2 Scattered solar radiation

3 Total radiation and radiation balance

Chapter 2. Influence of solar radiation on natural and economic processes

1 Solar radiation and climate

2 Effects of solar radiation on the development of plants and animals

Conclusion

Bibliography

Introduction

Solar radiation refers to the entire radiation flux emitted by the Sun, which is electromagnetic oscillations of various wavelengths. From a hygienic point of view, the optical part of sunlight, which occupies the range from 280-2800 nm, is of particular interest. Longer waves - radio waves, shorter - gamma rays, ionizing radiation do not reach the Earth's surface, because they are retained in the upper atmosphere, in the ozone layer in particular. Solar radiation is the main source of energy for all physical and geographical processes occurring on the earth's surface and in the atmosphere.

The study of this problem is of great importance, because all wildlife is sensitive to seasonal changes in ambient temperature, to the intensity of solar radiation - trees are covered with foliage in spring, foliage falls off in autumn, metabolic processes fade, many animals hibernate, etc. Man is no exception. Throughout the year, his metabolic rate changes, the composition of tissue cells, and these fluctuations are different in different climatic zones... So, in the southern regions, the hemoglobin content and the number of erythrocytes, as well as the maximum and minimum blood pressure in the cold period increase by 20 percent compared with the warm season. In the North, the highest percentage of hemoglobin was found in the majority of the surveyed residents in the summer months, and the lowest in winter and early spring. Recently, due to a sharp increase in environmental pollution, an increase in the content of carbon dioxide in the atmosphere, an increase in the background radiation, the number of spontaneous, spontaneous, harmful mutations in both animals and humans has significantly increased.

Course work "Solar radiation and its impact on natural and economic processes" is descriptive in nature, involves the development of knowledge within the framework of this problem.

The purpose of this work is to determine the role of solar radiation in natural and economic processes.

To achieve the goal, the following tasks have been set:

collect and study literature on solar radiation;

to characterize the behavior of solar radiation in terrestrial conditions;

consider the importance of solar radiation on natural and economic processes.

To implement the goals and objectives, the following research methods were used: analysis of scientific and methodological literature on the research topic, collection of information, comparison, generalization, systematization.

Subject of research: The impact of solar radiation on physiological processes on the planet Earth. Research object: Direct and diffuse solar radiation. The course work consists of an introduction, two parts, a conclusion and a list of references, including 10 sources.

Chapter 1. Theoretical aspects of solar radiation

1 Absorption and scattering of direct solar radiation in the atmosphere

The main source of energy for almost all natural processes occurring on the earth's surface and in the atmosphere is radiant energy coming to the Earth from the Sun. The energy coming to the surface of the earth from its deep layers, released during radioactive decay, brought by cosmic rays, as well as the radiation coming to the earth from stars, are negligible compared to the energy coming to the earth from the sun. In addition to radiant energy, i.e., electromagnetic waves, various streams of charged particles, mainly electrons and protons, moving at speeds of hundreds and thousands of km / sec, also come to the Earth from the Sun. Most of the radiant energy emitted by the sun is ultraviolet, visible and infrared rays. This part of the electromagnetic radiation of the Sun is called solar radiation in meteorology.

Solar radiation arriving at the upper boundary of the atmosphere, on its way to the earth's surface, undergoes a number of changes caused by its absorption and dissipation in the atmosphere. Radiation coming from the Sun into the atmosphere and then onto the earth's surface in the form of a parallel beam of rays is called direct. A significant part of the direct radiation reaching the upper boundary of the atmosphere reaches the earth's surface. Part of the solar radiation is scattered by molecules of atmospheric gases and aerosols and arrives at the earth's surface in the form of scattered radiation. Passing through the earth's atmosphere, solar radiation is attenuated due to absorption and scattering by atmospheric gases and aerosols. At the same time, its spectral composition also changes. Lines and bands appear in the spectrum due to absorption in the earth's atmosphere and are called telluric. In fig. 1 shows the distribution of energy in the solar spectrum. Curve a approximately characterizes its distribution outside earth's atmosphere, and curves b and c - on the earth's surface at sun heights of 35 and 15 °. On curves b and c, the ultraviolet part of the spectrum is cut off on the left at X = 0.29 μm, since ultraviolet radiation with a shorter wavelength is completely absorbed by the upper layers of the atmosphere. Part of the spectrum with X< 0,29 мкм можно наблюдать только на высотах более 30 км. Ультрафиолетовая же радиация с Х >0.29 microns, reaching the earth's surface, has very little energy. The short-wavelength part of the visible radiation and, to a lesser extent, the long-wavelength, visible and infrared part of the solar spectrum is also strongly attenuated when passing through the atmosphere. In the infrared part of the spectrum, there are a number of absorption bands caused by the presence of water vapor in the atmosphere. At different heights of the sun and different heights of the observation point above the earth's surface, the mass of the atmosphere passed through by the sunbeam is not the same. As a result, the spectral composition of solar radiation is also different. With a decrease in the height of the sun, the ultraviolet part of the radiation is especially strongly reduced, slightly less visible and only slightly infrared.

Rice. 1. Distribution of energy in the solar spectrum.

a - at the upper boundary of the atmosphere,

b - on the earth's surface at a sun height of 35 °,

c - on the earth's surface at a sun height of 15 °.

Water vapor plays an important role in the absorption of long-wave radiation: the more water vapor in the atmosphere, the less direct radiation reaches the Earth, all other things being equal. Comparison of curves a, b and c in Fig. 1 shows how significantly the atmosphere changes the initial distribution of energy in the solar radiation spectrum. Scattering of radiation in the atmosphere occurs mainly by molecules of atmospheric gases and aerosols (dust particles, droplets of fog, clouds, etc.). The scattering intensity depends on the number of scattering particles per unit volume, on their size and nature, as well as on the wavelengths of the scattered radiation itself. Below are the values of the dissipation coefficient in clean and dry air at normal pressure for different wavelengths

solar radiation atmosphere pressure

Table 1 Dissipation factors in clean and dry air at normal pressure

λ , μm 0.7600.5890.4860.396K 10 7(red) (yellow) (blue) (purple) 0.310.861.94.4

Table 1 shows that the shorter the wavelength, the more the rays are scattered, for example: violet scatters are 14 times stronger than red ones. This, in particular, explains the blue color of the sky. Although violet and blue rays are scattered even more than blue, their energy is significantly less. Therefore, the diffused light is dominated by blue color.

The scattering of radiation occurs in all directions, however, not with the same intensity. The most intense scattering occurs in the direction of the incident beam (forward) and in the opposite direction (backward). Scattering minima are observed in directions perpendicular to the direct ray. This is how scattering occurs in perfectly clean and dry air. The fraction of short waves in scattered radiation is greater than in direct radiation. Therefore, the longer the path of the sun's rays, the more short waves are scattered and the greater the proportion of long waves becomes. This explains, for example, that the sun and moon near the horizon acquire a yellow or even reddish color.

The direct radiation flux and its spectral composition depend on the height of the sun and the transparency of the atmosphere. The latter, in turn, depends on the content of absorbing gases and aerosols, in particular on the presence of clouds and fog. Under the influence of these factors, the direct radiation flux can vary over a wide range. At the same height of the sun, the flux of direct radiation in low latitudes, where the atmosphere contains a lot of water vapor and dust, should be less than in high latitudes. However, the transparency of the atmosphere affects this flow in much the same way as the height of the sun, on which the number of passable masses depends.

The flux of direct radiation increases with an increase in the altitude of the site above sea level, since the higher the observation point is, the smaller the thickness of the atmosphere is penetrated by the sun's rays and the less they are attenuated. The increase in the flux of direct radiation with height in the lower atmosphere is faster than in the upper, since most of the aerosols and water vapor are concentrated at the bottom. Clouds have an extremely large effect on direct radiation. Dense clouds of the lower tier practically do not allow direct radiation to pass through.

If the transparency of the atmosphere did not change during the day, then the change in direct radiation would be symmetric relative to true noon: from zero at the time of sunrise, it first quickly, and then more slowly, would increase to the maximum value reached at noon, and then just as smoothly. slowly at first, and then more quickly, it decreased to zero at the time of sunset. The currents would be the same at hours symmetrical about noon.

But the transparency of the atmosphere during the day does not remain constant, since the amount of dust, water vapor and other impurities contained in the air is constantly changing. Therefore, the diurnal variation of direct radiation is usually not symmetrical with respect to noon. In the hours close to noon or afternoon, as a result of the intensification of the ascending air movements, raising dust and water vapor, direct radiation begins to decrease, so that its maximum value is observed not at noon, but at about 10 hours

The daily course of direct radiation also changes throughout the year, as the length of the day and the height of the sun change. The daily variation of the direct radiation entering the perpendicular to the rays and on the horizontal surface is also different due to the unequal angle of incidence of the rays on these surfaces. In fig. 2 shows the diurnal variation of direct radiation entering the perpendicular to the rays and on the horizontal surface in Pavlovsk (near St. Petersburg).

Rice. 2. Diurnal variation of direct solar radiation in Pavlovsk. Solid lines - on the surface perpendicular to the rays; broken lines - on a horizontal surface

As can be seen from this figure, the arrival of direct radiation on a horizontal surface at all hours of the day is less than on a surface perpendicular to the rays. This difference is especially great in winter, when the height of the sun is low.

The daily variation of direct radiation also depends on the latitude of the place: in low latitudes, the maximum at noon hours is much more pronounced than in high ones. The reason is that as you get closer to the pole, the height of the sun changes less during the day. At the poles, for example, the change in the height of the sun during the day is so insignificant that here the daily variation of direct radiation is practically absent.

The annual course of direct radiation is characterized by a change in its mean monthly midday values. The most pronounced annual course of direct radiation at the pole. In the winter half of the year, solar radiation is absent here, and by the time of the summer solstice it can reach 1.30 cal / cm 2· Min. At the equator, on the contrary, the amplitude of the annual course of direct radiation is the smallest. In addition, at the equator, the annual course of direct radiation has the form of a double wave. Highs as high as 1.32 cal / cm 2Min., Fall on the days of the spring and autumn equinox, and the minimums, which are about 0.80 cal / cm 2min., - on the days of the summer and winter solstices. In middle latitudes, in the annual course of the midday direct radiation, the maximum should have been observed at the time of the summer solstice, when the sun's height is highest, and the minimum at the time of the winter solstice, when it is lowest. This is due to the fact that in the summer months, due to an increase in the content of water vapor and dust in the air, the transparency of the atmosphere is greatly reduced. Of great importance for agriculture, construction and the solution of a number of technical problems are data on the amounts of direct radiation received by a horizontal surface per day, month, year. Distinguish between theoretical, possible and actual amounts of direct radiation. The theoretical sum is the amount of radiation coming from the Sun over a given period of time per unit of horizontal surface located on the outer edge of the atmosphere

The possible sum is the amount of radiant energy that would enter this place with an average transparency of the atmosphere for it and in the complete absence of clouds for a given period of time to a single horizontal area located on the earth's surface. The actual amount of direct radiation is called its actual amount received over a given period of time on a single horizontal area located on the earth's surface. The actual amounts are found by processing the actinograph records or from the actinometer observations, taking into account the duration of the sunshine, established from the heliograph records.

Table 2 Daily sums of direct radiation on different days in Kharkov (cal / cm 2)

Amount 16 / III15 / IV15 / XI16 / XII Theoretical Possible Actual 519.6 305.3 116.8985.2 584.3 361.6610.4 365.0 215.1167.9 77.0 11.8

Table 2 shows the theoretical, possible and actual daily amounts of direct radiation in Kharkov in different time of the year. Table data. 2 indicate that the atmosphere plays a large role in the weakening of solar radiation (even on clear days with an average transparency of the atmosphere, the earth's surface receives only about 60% of the solar energy arriving at the upper boundary of the atmosphere), as well as cloudiness (it significantly reduces the arrival of direct radiation compared to with its possible amounts).

Observations show that the actual amounts of direct radiation in the spring and summer months increase slightly from high to low latitudes, with the exception of the polar regions, where they decrease sharply. Autumn and winter amounts decrease significantly with increasing latitude, which also leads to a strong decrease in annual amounts in the same direction.

1.2 Scattered solar radiation

The arrival of scattered radiation on the earth's surface can reach several tenths of cal / cm 2· Min. The following dependencies are observed.

The higher the height of the sun, the greater the flux of scattered radiation.

The more scattering particles in the atmosphere, the more solar radiation is scattered. Consequently, the flux of scattered radiation increases with increasing turbidity of the atmosphere.

The flux of scattered radiation increases significantly in the presence of light and relatively thin clouds, which represent a well-scattering medium. The influence of clouds illuminated by the sun from the side (Altocumulus, Cumulus) is especially great. Under the influence of such cloudiness, scattered radiation can increase by 8-10 times compared to its arrival with a clear sky. When the middle and especially the upper tier is overcast, the scattered radiation is 1.5-2 times greater than with a clear sky. Only with very strong overcast clouds and with precipitation is the scattered radiation less than with a clear sky.

The arrival of scattered radiation depends on the nature of the active surface, primarily on its reflectivity, since the radiation reflected from the surface is scattered again in the atmosphere and part of it again falls on the surface, where it is added to the initially scattered radiation. The snow cover especially noticeably increases the scattered radiation, reflecting up to 70-90% of the direct and scattered rays falling on it. The lower the height of the sun, the more the scattered radiation increases due to secondary scattering. Thus, snow cover increases the scattered radiation flux by 65% when the sun is near the horizon and by 12% when the sun is 50 °.

With an increase in altitude above sea level, scattered radiation in a clear sky decreases, since the thickness of the overlying scattering layers of the atmosphere decreases. But in the presence of clouds, scattered radiation in the subcloud layer of the atmosphere increases with height.

The diurnal and annual variation of scattered radiation in a cloudless sky is parallel to the course of direct radiation. But in the morning, scattered radiation appears earlier than direct radiation. Then, as the sun rises above the horizon, it increases, reaches a maximum at 12-13 o'clock, after which it begins to decrease and at the end of twilight it turns to zero. In the annual course, the maximum of scattered radiation with a clear sky is observed in July, and a minimum in January. The annual course of scattered radiation is also simple in case of continuous clouds. However, the described diurnal and annual variation of scattered radiation is greatly disturbed and complicated by variable cloudiness.

The amount of scattered radiation arriving at the earth's surface for any period of time is determined by the recording of recording instruments or by calculation based on the results of observations at separate times.

The daily amount of scattered radiation mainly depends on the height of the sun and the length of the day. Therefore, they grow with decreasing latitude and from winter to summer. Air transparency and cloudiness have a great influence on the arrival of scattered radiation.

Scattered radiation plays a particularly significant role at high latitudes and during the winter months. This is clearly seen, for example, from table. 3, in which, along with the sums of scattered radiation (∑ D), for comparison, the sums of direct radiation (∑ S ´ ) arriving on a horizontal surface.

Table 3 Seasonal and annual sums of direct (on a horizontal surface) and scattered radiation (cal / cm 2)

Item Amount of radiationWinterSpringSummerAutumnYear% Yakutsk ( φ = 62 °) ∑ S ´ 1.6 19.1 22.4 5.1 50.2 57 ∑ D2.613.815.45.537.343 Pavlovsk ( φ = 59.7 °) ∑ S ´ 0,915,122,74,142,856∑ D2,211,414,65,033,244 Karadag ( φ = 40 °) ∑ S ´ 4,522,036,714,077,264 D6,514,013,68,442,536

As you can see from the table. 3, in the winter months the sums of scattered radiation are everywhere greater than the sums of direct radiation, especially at high latitudes, where at this time even the midday heights of the sun are low. In summer, scattered radiation also plays an important role in areas with significant cloud cover (Yakutsk, Pavlovsk). In the annual amounts of radiant energy, the proportion of scattered radiation at high latitudes and in regions with a large amount of clouds exceeds 50%. For example, in Arkhangelsk it is 56%, in St. Petersburg 51%, etc.

1.3 Total radiation and radiation balance

Total radiation is the sum of a straight line (on a horizontal surface) and scattered radiation. The composition of the total radiation, that is, the ratio between direct and scattered radiation, changes depending on the height of the sun, transparency, atmosphere and cloudiness.

Before sunrise, the total radiation consists entirely, and at low altitudes of the sun - mainly of scattered radiation. With an increase in the height of the sun, the proportion of scattered radiation in the total in a cloudless sky decreases: at h = 8 ° it is 50%, and at h = 50 ° - only 10-20%.

The more transparent the atmosphere, the lower the proportion of scattered radiation in the total.

The daily and annual variation of the total radiation is determined mainly by the change in the height of the sun: the total radiation changes almost in direct proportion to the change in the height of the sun. But the influence of cloudiness and transparency of the air greatly complicates this simple relationship and disrupts the smooth course of the total radiation.

The total radiation also significantly depends on the latitude of the place. With a decrease in latitude, its daily amounts increase, and the lower the latitude of the place, the more uniformly the total radiation is distributed over the months, i.e., the smaller the amplitude of its annual cycle. For example, in Pavlovsk ( φ = 60 °) its monthly amounts are from 12 to 407 cal / cm 2, in Washington ( φ = 38.9 °) - from 142 to 486 cal / cm 2, and in Takubai ( φ = 19 °) - from 307 to 556 cal / cm 2... Annual sums of total radiation also increase with decreasing latitude. However, in some months the total radiation in the polar regions can be higher than in lower latitudes. For example, in Tikhaya Bay in June the total radiation is 37% more than in Pavlovsk, and 5% more than in Feodosia.

Continuous observations in Antarctica over the past 7-8 years show that the monthly sums of total radiation in this area in the warmest month (December) are about 1.5 times higher than at the same latitudes in the Arctic, and are equal to the corresponding sums in Crimea and in Tashkent. Even the annual amounts of total radiation in Antarctica are greater than, for example, in St. Petersburg. Such a significant arrival of solar radiation in Antarctica is explained by the dryness of the air, great height Antarctic stations above sea level and high reflectivity of the snow surface (70-90%), which increases scattered radiation

The difference between all fluxes of radiant energy arriving at and leaving the active surface is called the radiation balance of the active surface. In other words, the radiation balance of an active surface is the difference between the arrival and consumption of radiation on this surface. If the surface is horizontal, then the incoming part of the balance includes direct radiation arriving on the horizontal surface, scattered radiation and counter radiation of the atmosphere. The radiation consumption is made up of the reflected short-wave, long-wave radiation of the active surface and the part of the counter-radiation of the atmosphere reflected from it.

The radiation balance represents the actual arrival or consumption of radiant energy on the active surface, which determines whether it will be heated or cooled. If the arrival of radiant energy is greater than its consumption, then the radiation balance is positive and the surface heats up. If the income is less than the flow rate, then the radiation balance is negative and the surface is cooled. The radiation balance as a whole, as well as its individual constituent elements, depends on many factors. It is especially strongly influenced by the height of the sun, the duration of the sunshine, the nature and state of the active surface, the turbidity of the atmosphere, the content of water vapor in it, cloudiness, etc.

Instantaneous (minute) balance during the day is usually positive, especially in summer. Approximately 1 hour before sunset (excluding winter time), the consumption of radiant energy begins to exceed its arrival, and the radiation balance becomes negative. Approximately 1 hour after sunrise, it becomes positive again. The diurnal variation of the balance during the day with a clear sky is approximately parallel to the course of direct radiation. During the night, the radiation balance usually changes little, but under the influence of variable cloudiness, it can change significantly

The annual sums of the radiation balance are positive over the entire surface of land and oceans, except for areas with permanent snow or ice cover, for example, Central Greenland and Antarctica. North of 40 ° north latitude and south of 40 ° south latitude, the winter monthly sums of the radiation balance are negative, and the period with a negative balance increases towards the poles. So, in the Arctic, these amounts are positive only in the summer months, at 60 ° latitude - for seven months, and at 50 ° latitude - for nine months. The annual amounts of the radiation balance change during the transition from land to sea.

The radiation balance of the Earth-atmosphere system is the balance of radiant energy in a vertical column of the atmosphere with a cross section of 1 cm 2extending from the active surface to the upper boundary of the atmosphere. Its incoming part consists of solar radiation absorbed by the active surface and the atmosphere, and the outgoing part consists of that part of the long-wave radiation of the earth's surface and atmosphere that goes into world space. The radiation balance of the Earth-atmosphere system is positive in the belt from 30 ° south latitude to 30 ° north latitude, and at higher latitudes it is negative

The study of the radiation balance is of great practical interest, since this balance is one of the main climate-forming factors. The thermal regime of not only the soil or reservoir depends on its value, but also the layers of the atmosphere adjacent to them. Knowledge of the radiation balance is of great importance in calculating evaporation, in studying the formation and transformation of air masses, in considering the effect of radiation on humans and flora.

Chapter 2. Influence of solar radiation on natural and economic processes

2.1 Solar radiation and climate

The sun is the main force driving the climate system and even the smallest changes in the amount of solar energy can have serious consequences for the earth's climate. Solar activity increases and decreases every eleven years (or, as some experts believe, every twenty-two years) of the solar cycle. Over the past 3 million years, regular fluctuations in the amount of sunlight falling on the planet's surface have caused a series of ice ages, punctuated by short, warm interglacial intervals. According to Milankovitch's hypothesis, the Earth's hemisphere, as a result of changes in its motion, can receive less or more solar radiation, which is reflected in the global temperature. Over millions of years, many climatic cycles have changed. At the end of the last ice age, the ice cover, which for 100 thousand years chained the north of Europe and North America, began to decrease and disappeared 6 thousand years ago. Many scientists believe that the development of civilization falls mainly on the warm interval between ice ages.

Solar radiation arriving at the Earth's surface is the main energy base for the formation of the climate. It determines the main flow of heat to the earth's surface. The atmosphere heats up, absorbing both solar radiation and the earth's own radiation. The heated atmosphere radiates itself. Just like the earth's surface, it emits infrared radiation in the range of long waves invisible to the eye. A significant part (about 70%) of atmospheric radiation comes to the earth's surface, which almost completely absorbs it (95-99%). This radiation is called "counter-radiation", as it is directed towards the own radiation of the earth's surface. The main substance in the atmosphere that absorbs terrestrial radiation and sends the oncoming one is water vapor. In addition to water vapor, the atmosphere contains carbon dioxide (CO 2) and other gases that absorb energy in the wavelength range of 7-15 microns, i.e. where the energy of terrestrial radiation is close to the maximum. Relatively small changes in CO concentration 2in the atmosphere can affect the temperature of the earth's surface. By analogy with the processes occurring in greenhouses, when radiation penetrating through the protective film heats the earth, the radiation of which is delayed by the film, providing additional heating, this process of interaction of the earth's surface with the atmosphere is called the "greenhouse effect". The phenomenon of the greenhouse effect makes it possible to maintain the temperature on the Earth's surface at which the emergence and development of life is possible. If the greenhouse effect were absent, the average surface temperature the globe would be much lower than it is now.

The influence of external factors on the global air temperature is studied on the basis of modeling. Most of the work in this direction indicates that in the last 50 years, the projected rates and extent of warming due to the increase in greenhouse gas emissions are quite comparable to the rate and extent of the observed warming or exceed them. Changes in the concentration of greenhouse gases and aerosols in the atmosphere, changes in solar radiation and the properties of the earth's surface change the energy balance of the climate system. These changes are expressed in the term "radiative forcing", which is used to compare how a range of human and natural factors affect the global climate.

On the territory of Russia in winter, the total solar radiation reaches the highest values in the south of the Far East, in southern Transbaikalia and the Ciscaucasia. In January, the extreme south of Primorye receives over 200 MJ / m 2, the rest of the listed areas - over 150 mJ / km 2... To the north, the total radiation decreases rapidly due to the lower position of the Sun and a decrease in the length of the day. K 60 ° N it already decreases 3-4 times. North of the Arctic Circle, the polar night is established, the duration of which is 70 ° N. is 53 days. The radiation balance in winter is negative throughout the country.

Under these conditions, there is a strong cooling of the surface and the formation of the Asian Maximum centered over Northern Mongolia, southeastern Altai, Tuva, and the south of the Baikal region. The pressure in the center of the anticyclone exceeds 1040 hPa (mbar). Two spurs extend from the Asian maximum: to the northeast, where the secondary Oymyakon center with a pressure of over 1030 hPa is formed, and to the west, to the connection with the Azores maximum, - the Voeikov axis. It stretches through the Kazakh Uplands to Uralsk - Saratov - Kharkov - Chisinau and further down to the southern coast of France. In the western regions of Russia within the Voeikov axis, the pressure drops to 1021 hPa, but remains higher than in the territories located to the north and south of the axis.

The Voeikov axis plays an important role in the climate separation. To the south of it (in Russia it is the south of the East European Plain and the Ciscaucasia) east and north-east winds blow, carrying dry and cold continental air temperate latitudes from the Asian High. Southwestern and westerly winds blow to the north of the Voeikov axis. Role of western transport in the northern part of the East European Plain and in the northwest Western Siberia increases due to the Icelandic minimum, the trough of which reaches the Kara Sea (in the Varangerfjord area, the pressure is 1007.5 hPa). Relatively warm and humid Atlantic air often enters these regions with a westerly transfer. The rest of Siberia is dominated by winds with a southern component, carrying continental air from the Asian maximum. In fig. 3 shows that over the territory of the North-East in conditions of a depression relief and minimal solar radiation in winter, continental arctic air is formed, which is very cold and dry. From the northeastern spur of high pressure, it rushes towards the Arctic and Pacific oceans

Rice. 3. average temperature air in january

In winter, the Aleutian minimum is formed near the eastern shores of Kamchatka. On the Commander Islands, in the southeastern part of Kamchatka, in the northern part of the Kuril island arc, the pressure is below 1003 hPa, on a significant part of the Kamchatka coast, the pressure is below 1006 hPa. Here, on the eastern outskirts of Russia, the low pressure area is located in the immediate vicinity of the northeastern spur, therefore, a high pressure gradient is formed (especially near the northern coast of the Sea of Okhotsk); cold continental air of temperate latitudes (in the south) and arctic (in the north) is carried to the water area of the seas. The winds of the northern and northwestern points prevail. The Arctic front in winter is established over the water area of the Barents and Kara seas, and in the Far East - over Sea of Okhotsk... The polar front at this time passes south of the territory Russia. Only on the Black Sea coast of the Caucasus is the influence of the cyclones of the Mediterranean branch of the polar front affected, the paths of which shift from Western Asia to Black Sea due to the lower pressure over its open spaces. The distribution of precipitation is associated with the frontal zones.

With the onset of the warm period, the role of the radiation factor in climate formation increases sharply. He defines temperature regime almost throughout the country. The total radiation reaches the highest values in summer in the deserts of the Caspian region and on the Black Sea coast of the Caucasus - in July, 700 mJ / m2. To the north, the amount of solar radiation decreases little, due to the increase in the length of the day; therefore, in the north of Taimyr, it amounts to 550 mJ / m2 in July, i.e. 80% of the radiation arriving in the south of the country. In summer, the radiation balance and average monthly temperatures are positive throughout the country. The average temperature in July at the most northern islands Franz Josef Land and Severnaya Zemlya is close to zero, on the coast of Taimyr - a little more than + 2 ° С, in other coastal regions of Siberia + 4 ... + 6 ° С, and on the shores of the Barents Sea + 8 ... + 9 ° WITH. When moving to the south, the temperature quickly rises to +12 ... + 13 ° С. To the south, the rise in temperature is more gradual. The average July temperature reaches its maximum value of + 25 ° C in the deserts of the Caspian and Eastern Ciscaucasia.

In summer, the land warms up, the pressure over it decreases. Over Transbaikalia, the south of Yakutia and the middle Amur region, the pressure is below 1006 hPa, and over the south of Dauria even 1003 hPa. Towards the oceans, the pressure increases, reaching 1012 hPa over the northern waters of the East Siberian and Chukchi Seas, over The Barents Sea and west coast New Earth. Air masses rush inland. Arctic air is cold and dry, especially in the eastern regions of the Arctic. Moving south, it quickly warms up and moves away from the saturation state. The Hawaiian (North Pacific) maximum in summer moves northward, approaching the Russian Far Eastern borders, resulting in a summer monsoon. The mainland receives sea Pacific air of temperate latitudes, and sometimes tropical. In connection with the displacement of the Azov maximum to the north, its spur penetrates the East European Plain. To the north and east of it, the pressure decreases. In the summer, the western transport intensifies. Sea air of temperate latitudes enters the territory of Russia from the Atlantic.

Everything air masses that come to the territory of Russia in summer are transformed into continental air of temperate latitudes. An Arctic front appears over the northern seas, east of Taimyr, over the coastal regions of Siberia. The Mongolian branch of the polar front passes over the mountains of southern Siberia, and over central regions Of the East European Plain and Primorye, an intra-mass front arises between the poorly transformed sea and continental air of temperate latitudes

2.2 The impact of solar radiation on the development of plants and animals

In the previous part of this course work, the relationship was established between the incoming solar radiation and the Earth's surface. Thanks to this relationship, solar radiation has an active effect on a variety of processes on Earth, including its biosphere. IN AND. Vernadsky, speaking of the factors influencing the development of the biosphere, pointed out, among others, solar radiation. So, he emphasized that without cosmic luminaries, in particular without the Sun, life on Earth could not exist. Living organisms transform solar radiation into terrestrial energy (thermal, electrical, chemical, mechanical) on a scale that determines the existence of the biosphere. By processing solar energy, living matter transforms our entire planet. In this sense, we can assume that the origin, formation and functioning of the biosphere is the result of the action, including solar radiation

Part of the sun's radiant energy arriving at the earth is transmitted by electromagnetic waves with a wavelength of 300 ... 4000 nm. For plants, the most important is the area of physiological radiation, which has a significant effect on the processes of photosynthesis, growth and development. Of the physiological radiation coming to plants, they absorb about 80%, reflect 10 and transmit 10%. For photosynthesis and other physiological processes, plants use up to 6% of the absorbed radiation, the rest goes for heat transfer and transpiration. The spectral composition of light strongly affects the nature of plant growth and development. Plant pigments absorb radiation in the range of 320 ... 760 nm. The main absorption maxima are in the blue-violet and red, and the minimum is in the yellow-green region of the spectrum. Ultraviolet rays are largely absorbed by protein molecules, which can cause serious damage. Another two important chromophores that absorb ultraviolet rays are endogenous phytohormones. Thanks to them, ultraviolet rays affect the growth and development processes - there is a disproportionate growth of organs, a violation of the ratio in the growth of the root and shoot, the formation of plants with a compact (alpine) habit. Part of ultraviolet and blue radiation with a wavelength of no more than 510 nm is absorbed by the little-studied pigment cryptochrome. Blue light is absorbed by carotenoids and chlorophyll, red by chlorophyll, red and far red by phytochrome. Radiation with a longer wavelength is already absorbed not by special pigments, but by the entire surface of the plant, as a result of which its temperature rises. This can be observed in sowing: the upper tiers of leaves capture and reflect mainly the light of the visible short-wavelength part of the spectrum; mainly long-wave radiation penetrates to the lower leaves, which, against the background of weakened photosynthetic activity, significantly activates their respiration. Under the influence of this radiation, the stems are stretched, as a result of the lengthening of internodes, a loose tissue with large cells is formed, which is easily damaged by ultraviolet radiation, which often occurs when planting grown with thickening and overgrown seedlings

Radiant energy, causing changes in the course of physiological processes, is ultimately a powerful factor in the formation of plants. The duration of the illumination determines and often changes the appearance of the plant. So, on a short (8-10 - hour) day, long-day plants form a large number of leaves or branching shoots, many species (lettuce, rudbeckia, radish, etc.) form a rosette of leaves, their stem is shortened. Under the same conditions, short-day plants are undersized, the number of leaves is small, inflorescences (for example, panicles in millet, rice) are small, and the number of seeds formed is also insignificant. With an increase in the photoperiod (over 14-16 hours), development is delayed, and growth can significantly increase, as a result of which even such phenomena of gigantism are often observed as an abundance of leaves on a long stem, the appearance of many axillary shoots, branchiness of an ear, double flowers, multi-tubercle, an increase the number and size of flowers and seeds in each inflorescence. The length of the day affects the change in the ratio between the aboveground and underground organs, and also regulates the formation of stem thickenings, tubers, root crops and bulbs in such plants as radishes, onions, carrots, potatoes, dahlias. So, for example, radishes and potatoes, being delayed in development for a short day, send assimilants to the root crop or tubers. As a result of selection, varieties were selected that were capable of forming a root crop on a long day (for example, in radishes) or after flowering tubers in potatoes. The length of the day affects the differentiation of sex: in cannabis, on a long day, half of the plants are male, half are female, and on a short day, when development is faster, half of the plants are bisexual, and half are female. A short day accelerates the formation of female flowers in cucumbers and melons, and corn cobs. The combination of different day lengths and fluxes with different spectral composition of radiation (or with different ratios of energy, for example, red and blue rays in the emission of "white" light lamps) further affects morphogenetic changes.

In the dark or at low radiation intensity, etiolation of plants is usually observed (stretching and thinning of the stem and leaves, increased stretching of the petioles, etc.) mainly due to the elongation of cells in length - a process biologically aimed at bringing organs to light, as is the case , for example, on a stem that forms in the soil during seed germination. Light inhibits stretching, and the stronger, the higher its intensity. At the same day length, depending on the spectral composition of light and its intensity, the height of the plant and its shape change: at low intensity, the most compact and low-growing plants, although with a large number of leaves, are formed under the action of orange-red, and at high intensities - under the influence of blue-violet rays.

When some plant species were illuminated only with red light, the formation of leaves with a simpler and elongated plate, with a smaller number of shares was observed (for example, in radishes, tomatoes, etc.). A number of aquatic plants, which are characterized by the phenomenon of heterophilia (leaves of different shapes), form, under the action of red or green light, only ribbon-like, simple-shaped leaves; however, in blue or white light, normal and more complex leaves develop. In general, for all plants, the presence of blue-violet rays in the radiation is necessary, without which, to one degree or another, sooner or later, abnormal growth, development, anomalies in differentiation, etc. a powerful regulatory factor influencing changes in morphogenetic processes

The presence in plants and their organs of a number of photoreceptor systems, differing in absorption spectra and thereby determining the spectra of the processes and their interaction under irradiation with white light, creates the basis for an extraordinary variety of plant properties and traits - traits, the quantitative and qualitative expression of which depends on various influences. Thus, the most diverse processes in plant life are regulated by radiant energy, the source of which in natural conditions is radiation emitted by the Sun.

The influence of solar radiation on animals is very important and diverse. Solar radiation has a powerful biological effect, stimulates physiological processes in the body, changes metabolism and the general tone of the body. The biological effect of rays on the body depends on the wavelength - the shorter the wavelength, the stronger their biological effect. The most powerful effect is exerted by ultraviolet rays. They stimulate protein, fat, carbohydrate and mineral metabolism. Their effect on the function of hematopoiesis and immunological processes was noted, which leads to an increase in the body's defenses. Under the influence of UV light, vitamin D is formed in the skin of animals from the provitamin 7-dehydrocholesterol. 3regulating phosphorus-calcium metabolism and protecting young individuals from rickets, and adults from osteomalacia.

The bactericidal effect of UVL is of great importance, as a result of which air, soil, and water are disinfected. The most characteristic reaction of the human body to UV light is the development of pigmentation (sunburn). An overdose of ultraviolet radiation can lead to burns and skin irritation, headaches, and an increase in body temperature.

Infrared rays are thermally active. In order to improve the physiological state, growth, development and safety of young animals, as well as to create an optimal temperature and humidity regime in the premises in the autumn and winter-spring seasons, local heating with infrared lamps is widely used. Infrared rays raise the air temperature, warm up the skin and deep-lying tissues, promote blood flow to peripheral blood vessels, thereby creating a thermal barrier that prevents the cooling of the body. IR rays improve heat regulation and help to harden the body of young farm animals

Visible light provides the orientation of animals in space, increases motor activity due to the activation of neuromuscular tone. Visible light irritates the optic nerve, excites the nervous system and endocrine glands, and through them acts on the entire body. Under the influence of light in animals, the secretion of the gonads is increased and the sexual function is stimulated. A lack of light in growing animals can cause irreversible qualitative changes in the gonads, and in adult animals it reduces sexual activity, fertility, or causes temporary infertility. So, for example, in gilts and boars raised in conditions of insufficient illumination, the mass of ovaries and testes is 20-24% lower than in analogous animals kept in conditions of normal illumination.

The maintenance of breeding boars with illumination of 100-150 lx and a day length of 9-10 hours has a positive effect on their potency and sperm quality. The activity of the ovaries and the manifestation of sexual heat in cows also largely depends on the light factor. Optimal for them is 16-hour illumination. Practical observations show that cows kept in the outer rows of stalls near the windows come to hunt and fertilize faster than cows in the central rows of stalls, where the illumination is 5-10 times lower.

The illumination of the premises is of particular importance for birds. The use of a differentiated light regime, depending on the age and period of laying, allows to ensure uniform year-round egg production. A decrease in the intensity of illumination reduces the motor activity of animals, which leads to a more efficient use of feed energy, an increase in average daily weight gain, and therefore it is recommended to keep fattened animals in darkened rooms. However, at the same time, a large proportion of fat accumulates in the meat and the proportion of protein decreases. In conditions of darkening in animals, the strength of the long bones decreases. Excessively bright lighting leads to increased aggressiveness and cannibalism

Given the multifaceted effect of solar radiation, animals should be housed in fairly bright rooms, regularly provided with exercise, and in the summer they should be kept in pasture or in summer camps. Thus, under the influence of sunlight, the general tone of the body, the resistance of its infection, the natural resistance and productivity of animals increase.

Conclusion

For many millennia, people perceived only the visible part of the wave radiation of the Sun. Later it was discovered that the sun emits not only visible, but also invisible to the naked eye light, as well as charged particles. It was found that solar radiation is capable of transforming the Earth's atmosphere and interacting with its surface.

To summarize this term paper that solar radiation strongly affects the Earth only in the daytime, of course - when the Sun is above the horizon. Also, solar radiation is very strong near the poles, during the polar days, when the Sun is above the horizon even at midnight. It is shown that the amount of radiation received by a celestial body depends on the distance between the planet and the star - when the distance is doubled, the amount of radiation coming from the star to the planet decreases fourfold (in proportion to the square of the distance between the planet and the star). Thus, even small changes in the distance between the planet and the star (depending on the eccentricity of the orbit) lead to a significant change in the amount of radiation entering the planet.

The radiation balance, for example, on the northernmost islands of Russia is negative; in the mainland it varies from 400 mJ / m2 in the extreme north of Taimyr to 2000 mJ / m 2in the extreme south of the Far East, in the lower reaches of the Volga and in the Eastern Ciscaucasia. Maximum value (2100 mJ / m 2) the radiation balance reaches in the Western Ciscaucasia. The radiation balance determines the amount of heat that is spent on various processes occurring in nature. Consequently, near the northern continental outskirts of Russia, natural processes, and primarily climate formation, consume five times less heat than in its southern outskirts.

However, the amount of incoming solar radiation depends much more strongly on the changes of the seasons - at present, the total amount of solar radiation entering the Earth remains practically unchanged, but at latitudes 65 ° north latitude (latitude of northern cities of Russia, Canada) in summer, the amount of incoming solar radiation more than 25% more than in winter. This is due to the fact that the Earth is tilted at an angle of 23.3 degrees in relation to the Sun. Winter and summer changes are mutually compensated, but nevertheless, as the latitude of the observation site increases, the gap between winter and summer becomes more and more, so, at the equator, there is no difference between winter and summer. In the Arctic Circle, solar radiation is very high in summer and very little in winter. This shapes the climate on Earth. In addition, periodic changes in the eccentricity of the Earth's orbit can lead to the emergence of various geological eras: for example, the Ice Age. Factors affecting biogeochemical processes and the Earth's climate are determined by its spatial location relative to the Sun (inclination of the Earth's axis to the plane of the Earth's orbit), the distance of the Earth from the Sun, the conditions for the passage of sunlight and mainly the processes occurring on the Sun, which are generally called solar activity. The basis of solar-terrestrial connections is the influence of solar activity on the instability of technical processes that take place on the Earth, in its atmosphere and near-Earth space.

As a result of the work done, the main conclusions have been identified:

Direct solar radiation entering the Earth and scattered solar radiation reflected from the earth's surface are the main sources of energy on the planet.

Solar radiation, which supplies heat and light to the Earth, is of paramount importance in the genesis of climate, representing the main cause of almost all meteorological phenomena and processes occurring on the earth's surface and in the atmosphere.

Solar radiation is one of the important factors the life of plants and animals, which largely determines their productivity.

Bibliography

1. Shulgin I.A. - Solar radiation and plant. SPb .: Gidrometizdat, 2005 .-- 234 p.

Kuznetsov V.N., Idlis G.M., Gushchina V.N. - Natural science. M .: Agar,

Mamontov G.S., Zakharov V.B. - General biology. M .: Higher school,

Ku-Nan Liou. - Fundamentals of radiation processes in the atmosphere, St. Petersburg: Gidrometizdat, 2000. - 217 p.

Nikiforov G.S. - Health Psychology, St. Petersburg: Peter, 2003 .-- 255 p.

Sharov V.B. - Health and radiation, Chelyabinsk: Ural-Siberian House of Economic and Scientific and Technical Literature, 2002. - 189 p.

V.I. Katonov, S.G. Pliniev - About agriculture, M :. L. Selkhozgiz, 2010 .-- 302 p.

Markov, V.M. - Vegetable growing, M .: Kolos; Edition 2, revised,

Vrakin V.F., Sidorova M.V. - Morphology of agricultural animals. M .: "Agropromizdat", 2005. - 539s.

10. Obolensky V.N., - Meteorology, Moscow: Gidrometeizdat, 2004. - 638p.

Heat sources. Thermal energy is of decisive importance in the life of the atmosphere. The main source of this energy is the Sun. As for the thermal radiation of the Moon, planets and stars, it is so negligible for the Earth that it practically cannot be taken into account. Significantly more heat energy is provided by the internal heat of the Earth. According to the calculations of geophysicists, the constant influx of heat from the bowels of the Earth increases the temperature of the earth's surface by 0 °, 1. But such an influx of heat is still so small that there is no need to take it into account either. Thus, only the Sun can be considered the only source of thermal energy on the Earth's surface.

Solar radiation. The sun, which has a photosphere (radiating surface) temperature of about 6000 °, radiates energy into space in all directions. Some of this energy in the form of a huge beam of parallel solar rays hits the Earth. Solar energy that has reached the surface of the Earth in the form of direct rays of the Sun is called direct solar radiation. But not all solar radiation directed to the Earth reaches the earth's surface, since the sun's rays, passing through a thick layer of the atmosphere, are partially absorbed by it, partially scattered by molecules and suspended air particles, some are reflected by clouds. That part of the solar energy that is dissipated in the atmosphere is called scattered radiation. Scattered solar radiation spreads in the atmosphere and reaches the Earth's surface. We perceive this type of radiation as uniform daylight when the Sun is completely covered by clouds or has just disappeared behind the horizon.

Direct and scattered solar radiation, reaching the surface of the Earth, is not completely absorbed by it. Part of the solar radiation is reflected from the earth's surface back into the atmosphere and is there in the form of a beam of rays, the so-called reflected solar radiation.

The composition of solar radiation is very complex, which is associated with a very high temperature the radiating surface of the sun. Conventionally, by wavelength, the solar radiation spectrum is divided into three parts: ultraviolet (η<0,4<μ видимую глазом (η from 0.4μ to 0.76μ) and infrared part (η> 0.76μ). In addition to the temperature of the solar photosphere, the composition of solar radiation near the earth's surface is also affected by the absorption and scattering of part of the sun's rays as they pass through the Earth's air envelope. In this regard, the composition of solar radiation at the upper boundary of the atmosphere and at the surface of the Earth will be different. Based on theoretical calculations and observations, it has been established that at the border of the atmosphere, ultraviolet radiation accounts for 5%, visible rays - 52% and infrared - 43%. At the earth's surface (at a height of the Sun of 40 °), ultraviolet rays are only 1%, visible - 40%, and infrared - 59%.

Solar radiation intensity. The intensity of direct solar radiation is understood as the amount of heat in calories received in 1 minute. from the radiant energy of the Sun with a surface of 1 cm 2, located perpendicular to the sun's rays.

To measure the intensity of direct solar radiation, special devices are used - actinometers and pyrheliometers; the amount of scattered radiation is determined by a pyranometer. Automatic registration of the duration of the action of solar radiation is carried out by actinographs and heliographs. The spectral intensity of solar radiation is determined by a spectrobolograph.

At the border of the atmosphere, where the absorbing and scattering effect of the Earth's air envelope is excluded, the intensity of direct solar radiation is approximately 2 feces by 1 cm 2 surface in 1 min. This value is called solar constant. Solar radiation intensity in 2 feces by 1 cm 2 in 1 min. generates such a large amount of heat throughout the year that it would be enough to melt a layer of ice in 35 m thick, if such a layer covered the entire earth's surface.

Numerous measurements of the intensity of solar radiation suggest that the amount of solar energy arriving at the upper boundary of the Earth's atmosphere experiences fluctuations in the amount of several percent. Oscillations are periodic and non-periodic, apparently associated with processes occurring on the Sun itself.

In addition, some change in the intensity of solar radiation occurs during the year due to the fact that the Earth in its annual rotation moves not in a circle, but in an ellipse, in one of the foci of which the Sun is located. In this regard, the distance from the Earth to the Sun changes and, consequently, the intensity of solar radiation fluctuates. The highest intensity is observed around January 3, when the Earth is closest to the Sun, and the lowest around July 5, when the Earth is at its maximum distance from the Sun.

For this reason, the fluctuation in the intensity of solar radiation is very small and can only be of theoretical interest. (The amount of energy at the maximum distance refers to the amount of energy at the minimum distance, like 100: 107, that is, the difference is completely negligible.)

Conditions of irradiation of the surface of the globe. Already the spherical shape of the Earth alone leads to the fact that the radiant energy of the Sun is distributed very unevenly on the earth's surface. So, on the days of the vernal and autumnal equinox (March 21 and September 23), only at the equator at noon, the angle of incidence of the rays will be 90 ° (Fig. 30), and as it approaches the poles, it will decrease from 90 to 0 °. In this way,

if at the equator the amount of radiation received is taken as 1, then at the 60th parallel it will be expressed in 0.5, and at the pole it will be equal to 0.

The globe, in addition, has daily and annual motion, and the earth's axis is inclined to the orbital plane by 66 °, 5. Due to this inclination, an angle of 23 ° 30 is formed between the equatorial plane and the orbital plane.This circumstance leads to the fact that the angles of incidence of sun rays for the same latitudes will vary within 47 ° (23.5 + 23.5) ...

Depending on the season, not only the angle of incidence of the rays changes, but also the duration of illumination. If in tropical countries at all seasons the length of day and night is approximately the same, in polar countries, on the contrary, it is very different. So, for example, at 70 ° N. sh. in summer the Sun does not set for 65 days, at 80 ° N. sh. - 134, and at the pole -186. Because of this, at the North Pole, radiation on the summer solstice (June 22) is 36% more than at the equator. As for the entire summer half of the year, the total amount of heat and light received by the pole is only 17% less than at the equator. Thus, in the summertime in polar countries, the duration of illumination largely compensates for the lack of radiation, which is a consequence of the small angle of incidence of the rays. In the winter half of the year, the picture is completely different: the amount of radiation at the same North Pole will be equal to 0. As a result, the average amount of radiation at the pole is 2.4 times less than at the equator per year. From all that has been said, it follows that the amount of solar energy that the Earth receives by radiation is determined by the angle of incidence of the rays and the duration of the irradiation.

The earth's surface in the absence of atmosphere at different latitudes per day would receive the following amount of heat, expressed in calories per 1 cm 2(see table on page 92).

The distribution of radiation on the earth's surface given in the table is usually called solar climate. We repeat that we have such a distribution of radiation only at the upper boundary of the atmosphere.

Attenuation of solar radiation in the atmosphere. So far, we have talked about the conditions for the distribution of solar heat over the earth's surface, without taking into account the atmosphere. Meanwhile, the atmosphere in this case is of great importance. Solar radiation passing through the atmosphere undergoes scattering and, moreover, absorption. Both of these processes together attenuate solar radiation to a great extent.

The sun's rays, passing through the atmosphere, first of all experience scattering (diffusion). Scattering is created by the fact that rays of light, refracting and reflecting from air molecules and particles of solids and liquids in the air, deviate from the direct path To really "dissipate".

Scattering greatly attenuates solar radiation. With an increase in the amount of water vapor and especially dust particles, the scattering increases and the radiation is weakened. In large cities and desert areas, where the air is most dusty, dispersion reduces the strength of radiation by 30-45%. Diffusion produces that daylight that illuminates objects, even if the sun's rays are not directly falling on them. The scattering determines the very color of the sky.

Let us now dwell on the ability of the atmosphere to absorb the radiant energy of the Sun. The main gases that make up the atmosphere absorb radiant energy comparatively very little. Impurities (water vapor, ozone, carbon dioxide and dust), on the contrary, are highly absorbent.

In the troposphere, the most significant admixture is water vapor. They absorb especially strongly infrared (long-wave), i.e., predominantly heat rays. And the more water vapor in the atmosphere, the naturally more and. absorption. The amount of water vapor in the atmosphere is subject to great changes. Under natural conditions, it varies from 0.01 to 4% (by volume).

Ozone has a very high absorption capacity. A significant admixture of ozone, as already mentioned, is in the lower layers of the stratosphere (above the tropopause). Ozone absorbs ultraviolet (shortwave) rays almost completely.

Carbon dioxide also has a high absorption capacity. It absorbs mainly long-wave, i.e., mainly heat rays.

Dust in the air also absorbs some of the solar radiation. When heated under the influence of sunlight, it can significantly increase the air temperature.

The atmosphere absorbs only about 15% of the total amount of solar energy coming to the Earth.

The attenuation of solar radiation by scattering and absorption by the atmosphere is very different for different latitudes of the Earth. This difference depends primarily on the angle of incidence of the rays. At the zenith position of the Sun, the rays falling vertically cross the atmosphere by the shortest path. With a decrease in the angle of incidence, the path of the rays lengthens and the attenuation of solar radiation becomes more significant. The latter is clearly seen from the drawing (Fig. 31) and the attached table (in the table, the magnitude of the path of the sunbeam at the zenith position of the Sun is taken as a unit).

Depending on the angle of incidence of the rays, not only the number of rays changes, but also their quality. During the period when the Sun is at its zenith (overhead), ultraviolet rays account for 4%,

visible - 44% and infrared - 52%. With the position of the Sun at the horizon, there are no ultraviolet rays at all, visible 28% and infrared 72%.

The complexity of the influence of the atmosphere on solar radiation is aggravated by the fact that its carrying capacity varies greatly depending on the season and weather conditions. So, if the sky remained cloudless all the time, then the annual course of the influx of solar radiation at different latitudes could be graphically expressed as follows (Fig., 32) It is clearly seen from the drawing that with a cloudless sky in Moscow in May, June and July, heat more solar radiation would be obtained than at the equator. Likewise, in the second half of May, in June and the first half of July, the North Pole would receive more heat than at the equator and in Moscow. We repeat that it would be so with a cloudless sky. But in fact, this does not work, because cloudiness significantly weakens solar radiation. Let's give an example, shown in the graph (Fig. 33). The graph shows how much solar radiation does not reach the Earth's surface: a significant part of it is retained by the atmosphere and clouds.

However, it must be said that the heat absorbed by the clouds partly goes to heating the atmosphere, and partly indirectly reaches the earth's surface.

Diurnal and annual variations in salt intensityradiation. The intensity of direct solar radiation near the Earth's surface depends on the height of the Sun above the horizon and on the state of the atmosphere (on its dustiness). If. the transparency of the atmosphere during the day was constant, the maximum intensity of solar radiation would be observed at noon, and the minimum - at sunrise and sunset. In this case, the graph of the course of the daily intensity of solar radiation would be symmetrical with respect to half a day.

The content of dust, water vapor and other impurities in the atmosphere is constantly changing. In this regard, the transparency of the air changes and the symmetry of the graph of the course of the intensity of solar radiation is violated. Often, especially in the summer, at noon, when the earth's surface is heated intensively, powerful ascending air currents arise, and the amount of water vapor and dust in the atmosphere increases. This leads to a significant reduction in solar radiation at noon; the maximum intensity of radiation in this case is observed in the midday or afternoon hours. The annual variation of the intensity of solar radiation is also associated with changes in the height of the Sun above the horizon during the year and with the state of transparency of the atmosphere in different seasons. In the countries of the northern hemisphere, the highest height of the Sun above the horizon occurs in the month of June. But at the same time, the highest dustiness of the atmosphere is also observed. Therefore, the maximum intensity usually falls not in the middle of summer, but in the spring months, when the Sun rises rather high * above the horizon, and the atmosphere after winter is still relatively clean. To illustrate the annual variation of the intensity of solar radiation in the Northern Hemisphere, we present data on the average monthly midday values of the radiation intensity in Pavlovsk.

The amount of heat from solar radiation. The surface of the Earth continuously receives heat during the day from direct and scattered solar radiation or only from scattered radiation (in cloudy weather). Determine the daily amount of heat on the basis of actinometric observations: by taking into account the amount of direct and scattered radiation received on the earth's surface. Having determined the amount of heat for every day, the amount of heat received by the earth's surface for a month or a year is also calculated.

The daily amount of heat received by the earth's surface from solar radiation depends on the intensity of the radiation and on the duration of its action during the day. In this regard, the minimum inflow of heat occurs in the winter, and the maximum in the summer. In the geographical distribution of the total radiation over the globe, its increase is observed with a decrease in the latitude of the area. This position is confirmed by the following table.

The role of direct and scattered radiation in the annual amount of heat received by the earth's surface at different latitudes of the globe is not the same. At high latitudes, scattered radiation predominates in the annual amount of heat. With decreasing latitude, the prevailing value is transferred to direct solar radiation. So, for example, in Tikhaya Bay, scattered solar radiation gives 70% of the annual amount of heat, and direct radiation only 30%. In Tashkent, on the contrary, direct solar radiation gives 70%, scattered only 30%.

Reflectivity of the Earth. Albedo. As already indicated, the Earth's surface absorbs only part of the solar energy that comes to it in the form of direct and scattered radiation. The other part is reflected in the atmosphere. The ratio of the magnitude of solar radiation reflected by a given surface to the magnitude of the flux of radiant energy falling on this surface is called albedo. Albedo is expressed as a percentage and characterizes the reflectivity of a given area of the surface.

Albedo depends on the nature of the surface (soil properties, the presence of snow, vegetation, water, etc.) and on the magnitude of the angle of incidence of the sun's rays on the Earth's surface. So, for example, if the rays fall on the earth's surface at an angle of 45 °, then:

From the examples given, it can be seen that the reflectivity of different objects is not the same. It is most of all in the snow and least of all in the water. However, the examples we have taken refer only to those cases when the height of the Sun above the horizon is 45 °. As this angle decreases, the reflectivity increases. So, for example, at the height of the Sun at 90 °, water reflects only 2%, at 50 ° - 4%, at 20 ° -12%, at 5 ° - 35-70% (depending on the state of the water surface).

On average, with a cloudless sky, the surface of the globe reflects 8% of solar radiation. In addition, 9% reflects the atmosphere. Thus, the globe as a whole with a cloudless sky reflects 17% of the sun's radiant energy falling on it. If the sky is covered with clouds, then 78% of the radiation is reflected from them. If we take natural conditions, based on the ratio between a cloudless sky and a sky covered with clouds, which is observed in reality, then the reflectivity of the Earth as a whole is 43%.

Terrestrial and atmospheric radiation. The Earth, receiving solar energy, heats up and itself becomes a source of heat radiation into world space. However, the rays emitted by the earth's surface are sharply different from the sun's rays. The Earth emits only long-wavelength (λ 8-14 μ) invisible infrared (heat) rays. The energy emitted from the earth's surface is called terrestrial radiation. Radiation from the Earth occurs and. day and night. The higher the temperature of the emitting body, the higher the radiation intensity. Terrestrial radiation is defined in the same units as solar radiation, i.e. in calories s 1 cm 2 surface in 1 min. Observations have shown that the amount of terrestrial radiation is small. Usually it reaches 15-18 hundredths of a calorie. But, acting continuously, it can produce a significant thermal effect.

The strongest terrestrial radiation is obtained with a cloudless sky and good transparency of the atmosphere. Clouds (especially low clouds) significantly reduce terrestrial radiation and often bring it to zero. Here we can say that the atmosphere, together with the clouds, is a good "blanket" that protects the Earth from excessive cooling. Parts of the atmosphere, like parts of the earth's surface, emit energy in accordance with their temperature. This energy is called atmospheric radiation. The intensity of atmospheric radiation depends on the temperature of the radiating part of the atmosphere, as well as on the amount of water vapor and carbon dioxide contained in the air. Atmospheric radiation belongs to the long-wave troupe. It spreads in the atmosphere in all directions; some of it reaches the earth's surface and is absorbed by it, the other part goes into interplanetary space.

O the arrival and consumption of the Sun's energy on Earth. The earth's surface, on the one hand, receives solar energy in the form of direct and scattered radiation, and on the other hand, it loses some of this energy in the form of terrestrial radiation. As a result of the arrival and consumption of solar "energy, some result is obtained. In some cases this result may be positive, in others negative. Let us give examples of both.

January 8. The day is cloudless. On 1 cm 2 the earth's surface received 20 feces direct solar radiation and 12 feces scattered radiation; in total, thus obtained 32 cal. During the same time, due to radiation 1 cm? ground surface lost 202 cal. As a result, in the language of accounting, there is a loss in the balance sheet of 170 feces(negative balance).

July 6. The sky is almost cloudless. From direct solar radiation received 630 feces, from scattered radiation 46 cal. In total, therefore, the earth's surface received 1 cm 2 676 cal. Lost by Earth Radiation 173 cal. In the balance sheet profit for 503 feces(the balance is positive).

From the above examples, among other things, it is quite clear why in temperate latitudes it is cold in winter and warm in summer.

The use of solar radiation for technical and domestic purposes. Solar radiation is an inexhaustible natural source of energy. The magnitude of solar energy on Earth can be judged by this example: if, for example, you use the heat of solar radiation, falling only on 1/10 of the area of the USSR, you can get energy equal to the work of 30 thousand Dneproges.

People have long sought to use the free energy of solar radiation for their needs. To date, many different solar installations have been created that operate on the use of solar radiation and are widely used in industry and to meet the household needs of the population. In the southern regions of the USSR, in industry and municipal services, on the basis of the widespread use of solar radiation, solar water heaters, boilers, salt water distillers, solar dryers (for drying fruits), kitchens, baths, greenhouses, and devices for medical purposes operate. Solar radiation is widely used in health resorts for the treatment and health promotion of people.

Solar radiation is all the energy of the Sun entering the Earth.

That part of the solar radiation that reaches the Earth's surface without obstruction is called direct radiation. The maximum possible amount of direct radiation is received by a unit of area located perpendicular to the sun's rays. If the sun's rays pass through clouds and water vapor, then it is scattered radiation.

The amount of solar radiation depends on:

1) the angle of incidence of the sun's rays

2) the duration of daylight hours

3) cloudiness.

The atmosphere absorbs about 23% of direct solar radiation. Moreover, this absorption is selective: different gases absorb radiation in different parts of the spectrum and to varying degrees.

The largest amount of solar radiation is received by the deserts lying along the lines of the tropics. The sun rises high there and the weather is cloudless for most of the year.

Above the equator, there is a lot of water vapor in the atmosphere, which forms dense clouds. Steam and cloudiness absorb most of the solar radiation.

The polar regions receive the least amount of radiation, where the sun's rays almost glide along the surface of the Earth.

The underlying surface reflects radiation in different ways. Dark and uneven surfaces reflect little radiation, while light and smooth surfaces reflect well.

A sea in a storm reflects less radiation than a sea in a calm.

Albedo (Latin albus - white) - the ability of a surface to reflect radiation.

Geographic distribution of total radiation

The distribution of annual and monthly amounts of total solar radiation over the globe is zonal: the isolines of the radiation flux on the maps do not coincide with latitudinal circles. These deviations are explained by the fact that the transparency of the atmosphere and cloudiness affect the distribution of radiation over the globe.

Annual amounts of total radiation are especially high in low-cloud subtropical deserts. But over the equatorial forest areas with their large clouds, they are reduced. Towards higher latitudes of both hemispheres, the annual amounts of total radiation decrease. But then they grow again - little in the Northern Hemisphere, but very significantly above the cloudy and snowy Antarctica. Over the oceans, the amount of radiation is lower than over land.

For the earth's surface, there is no radiation equilibrium in the reception and release of radiation, but there is a thermal equilibrium: the flow of heat to the earth's surface by both radiation and non-radiation routes is equal to its return by the same methods.