Causes of solar radiation. How does the impact

1. What is called solar radiation? In what units is it measured? On what does its value depend?

The totality of radiant energy sent by the Sun is called solar radiation, usually it is expressed in calories or joules per square centimeter per minute. Solar radiation is distributed unevenly over the earth. It depends:

From the density and humidity of the air - the higher they are, the less radiation the earth's surface receives;

From the geographical latitude of the area - the amount of radiation increases from the poles to the equator. The amount of direct solar radiation depends on the length of the path that the sun's rays travel through the atmosphere. When the Sun is at its zenith (the angle of incidence of the rays is 90 °), its rays hit the Earth in the shortest way and intensively give off their energy to a small area;

From the annual and daily movement of the Earth - in the middle and high latitudes, the influx of solar radiation varies greatly by season, which is associated with a change in the midday height of the Sun and the length of the day;

From the nature of the earth's surface - the lighter the surface, the more sunlight it reflects.

2. What are the types of solar radiation?

There are the following types of solar radiation: radiation reaching the earth's surface consists of direct and diffuse. Radiation that comes to Earth directly from the Sun in the form of direct sunlight in a cloudless sky is called direct. It carries the greatest amount of heat and light. If our planet had no atmosphere, the earth's surface would receive only direct radiation. However, passing through the atmosphere, about a quarter of the solar radiation is scattered by gas molecules and impurities, deviates from the direct path. Some of them reach the Earth's surface, forming scattered solar radiation. Thanks to scattered radiation, light also penetrates into places where direct sunlight (direct radiation) does not penetrate. This radiation creates daylight and gives color to the sky.

3. Why does the inflow of solar radiation change according to the seasons of the year?

Russia, for the most part, is located in temperate latitudes, lying between the tropic and the polar circle, in these latitudes the sun rises and sets every day, but never at its zenith. Due to the fact that the angle of the Earth's inclination does not change during its entire revolution around the Sun, in different seasons the amount of incoming heat in temperate latitudes is different and depends on the angle of the Sun above the horizon. So, at a latitude of 450 max, the angle of incidence of the sun's rays (June 22) is approximately 680, and min (December 22) is approximately 220. The smaller the angle of incidence of the Sun's rays, the less heat they bring, therefore, there are significant seasonal differences in the received solar radiation in different seasons of the year: winter, spring, summer, autumn.

4. Why is it necessary to know the height of the Sun above the horizon?

The height of the Sun above the horizon determines the amount of heat coming to the Earth, so there is a direct relationship between the angle of incidence of the sun's rays and the amount of solar radiation coming to the earth's surface. From the equator to the poles, in general, there is a decrease in the angle of incidence of the sun's rays, and as a result, from the equator to the poles, the amount of solar radiation decreases. Thus, knowing the height of the Sun above the horizon, you can find out the amount of heat coming to the earth's surface.

5. Choose the correct answer. The total amount of radiation reaching the Earth's surface is called: a) absorbed radiation; b) total solar radiation; c) scattered radiation.

6. Choose the correct answer. When moving towards the equator, the amount of total solar radiation: a) increases; b) decreases; c) does not change.

7. Choose the correct answer. The largest indicator of reflected radiation has: a) snow; b) black soil; c) sand; d) water.

8. Do you think it is possible to get a tan on a cloudy summer day?

The total solar radiation consists of two components: diffuse and direct. At the same time, the Sun's rays, independent of their nature, carry ultraviolet, which affects the tan.

9. Using the map in Figure 36, determine the total solar radiation for ten cities in Russia. What conclusion did you draw?

Total radiation in different cities of Russia:

Murmansk: 10 kcal/cm2 per year;

Arkhangelsk: 30 kcal/cm2 per year;

Moscow: 40 kcal/cm2 per year;

Perm: 40 kcal/cm2 per year;

Kazan: 40 kcal/cm2 per year;

Chelyabinsk: 40 kcal/cm2 per year;

Saratov: 50 kcal/cm2 per year;

Volgograd: 50 kcal/cm2 per year;

Astrakhan: 50 kcal/cm2 per year;

Rostov-on-Don: more than 50 kcal/cm2 per year;

The general pattern in the distribution of solar radiation is as follows: the closer an object (city) is to the pole, the less solar radiation falls on it (city).

10. Describe how the seasons of the year differ in your area (natural conditions, people's lives, their activities). In which season of the year is life most active?

Difficult relief, large extent from north to south make it possible to distinguish 3 zones in the region, differing both in relief and in climatic characteristics: mountain-forest, forest-steppe and steppe. The climate of the mountain-forest zone is cool and humid. The temperature regime varies depending on the relief. This zone is characterized by short cool summers and long snowy winters. Permanent snow cover is formed in the period from October 25 to November 5 and it lies until the end of April, and in some years the snow cover remains until May 10-15. The coldest month is January. The average temperature in winter is minus 15-16°C, the absolute minimum is 44-48°C. The warmest month is July with an average air temperature of plus 15-17°C, the absolute maximum air temperature in the summer in this area reached plus 37-38°C The climate of the forest-steppe zone is warm, with fairly cold and snowy winters. The average January temperature is minus 15.5-17.5°C, the absolute minimum air temperature reached minus 42-49°C. The average air temperature in July is plus 18-19°C. The absolute maximum temperature is plus 42.0°C The climate of the steppe zone is very warm and arid. The winter here is cold, with severe frosts, blizzards, which are observed for 40-50 days, causing a strong transfer of snow. The average January temperature is minus 17-18°C. In severe winters, the minimum air temperature drops to minus 44-46°C.

All types of solar rays reach the earth's surface in three ways - in the form of direct, reflected and diffuse solar radiation.
direct solar radiation are rays coming directly from the sun. Its intensity (efficiency) depends on the height of the sun above the horizon: the maximum is observed at noon, and the minimum - in the morning and evening; from the time of year: maximum - in summer, minimum - in winter; from the height of the terrain above sea level (higher in the mountains than on the plain); on the state of the atmosphere (air pollution reduces it). The spectrum of solar radiation also depends on the height of the sun above the horizon (the lower the sun is above the horizon, the less ultraviolet rays).
reflected solar radiation- These are the rays of the sun reflected by the earth or water surface. It is expressed as the percentage of reflected rays to their total flux and is called albedo. The albedo value depends on the nature of the reflecting surfaces. When organizing and conducting sunbathing, it is necessary to know and take into account the albedo of the surfaces on which sunbathing is carried out. Some of them are characterized by selective reflectivity. Snow completely reflects infrared rays, and ultraviolet rays to a lesser extent.

scattered solar radiation formed as a result of the scattering of sunlight in the atmosphere. Air molecules and particles suspended in it (the smallest droplets of water, ice crystals, etc.), called aerosols, reflect part of the rays. As a result of multiple reflections, some of them still reach the earth's surface; These are scattered rays of the sun. Mostly ultraviolet, violet and blue rays are scattered, which determines the blue color of the sky in clear weather. The proportion of scattered rays is large at high latitudes (in the northern regions). There the sun is low above the horizon, and therefore the path of the rays to the earth's surface is longer. On a long path, the rays meet more obstacles and scatter to a greater extent.

(http://new-med-blog.livejournal.com/204

Total solar radiation- all direct and diffuse solar radiation entering the earth's surface. Total solar radiation is characterized by intensity. With a cloudless sky, the total solar radiation has a maximum value around noon, and during the year - in summer.

Radiation balance
The radiation balance of the earth's surface is the difference between the total solar radiation absorbed by the earth's surface and its effective radiation. For the earth's surface
- the incoming part is the absorbed direct and scattered solar radiation, as well as the absorbed counter radiation of the atmosphere;
- the expenditure part consists of heat loss due to the own radiation of the earth's surface.

The radiation balance can be positive(daytime, summer) and negative(at night, in winter); measured in kW/sq.m/min.
The radiation balance of the earth's surface is the most important component of the heat balance of the earth's surface; one of the main climate-forming factors.

Thermal balance of the earth's surface- the algebraic sum of all types of heat input and output on the surface of land and ocean. The nature of the heat balance and its energy level determine the features and intensity of most exogenous processes. The main components of the ocean heat balance are:
- radiation balance;
- heat consumption for evaporation;
- turbulent heat exchange between the ocean surface and the atmosphere;
- vertical turbulent heat exchange of the ocean surface with the underlying layers; and
- horizontal oceanic advection.

(http://www.glossary.ru/cgi-bin/gl_sch2.c gi?RQgkog.outt:p!hgrgtx!nlstup!vuilw)tux yo)

Measurement of solar radiation.

Actinometers and pyrheliometers are used to measure solar radiation. The intensity of solar radiation is usually measured by its thermal effect and is expressed in calories per unit surface per unit of time.

(http://www.ecosystema.ru/07referats/slo vgeo/967.htm)

Measurement of the intensity of solar radiation is carried out by a Yanishevsky pyranometer complete with a galvanometer or a potentiometer.

When measuring total solar radiation, the pyranometer is installed without a shadow screen, while when measuring scattered radiation, with a shadow screen. Direct solar radiation is calculated as the difference between total and scattered radiation.

When determining the intensity of incident solar radiation on the fence, the pyranometer is installed on it so that the perceived surface of the device is strictly parallel to the surface of the fence. In the absence of automatic recording of radiation, measurements should be made after 30 minutes between sunrise and sunset.

Radiation falling on the surface of the fence is not completely absorbed. Depending on the texture and color of the fence, some of the rays are reflected. The ratio of reflected radiation to incident radiation, expressed as a percentage, is called surface albedo and measured by P.K. Kalitina complete with galvanometer or potentiometer.

For greater accuracy, observations should be carried out in a clear sky and with intense solar irradiation of the fence.

(http://www.constructioncheck.ru/default.a spx?textpage=5)

The blinding solar disk at all times excited the minds of people, served as a fertile topic for legends and myths. Since ancient times, people have guessed about its impact on the Earth. How close were our distant ancestors to the truth. It is the radiant energy of the Sun that we owe the existence of life on Earth.

What is the radioactive radiation of our luminary and how does it affect earthly processes?

What is solar radiation

Solar radiation is a combination of solar matter and energy entering the Earth. The energy propagates in the form of electromagnetic waves at a speed of 300 thousand kilometers per second, passes through the atmosphere and reaches the Earth in 8 minutes. The range of waves participating in this "marathon" is very wide - from radio waves to X-rays, including the visible part of the spectrum. The earth's surface is under the influence of both direct and scattered by the earth's atmosphere, the sun's rays. It is the scattering of blue-blue rays in the atmosphere that explains the blueness of the sky on a clear day. The yellow-orange color of the solar disk is due to the fact that the waves corresponding to it pass almost without scattering.

With a delay of 2–3 days, the “solar wind” reaches the earth, which is a continuation of the solar corona and consists of the nuclei of atoms of light elements (hydrogen and helium), as well as electrons. It is quite natural that solar radiation has a strong influence on the human body.

The effect of solar radiation on the human body

The electromagnetic spectrum of solar radiation consists of infrared, visible and ultraviolet parts. Since their quanta have different energies, they have a variety of effects on a person.

indoor lighting

The hygienic significance of solar radiation is also extremely high. Since visible light is a decisive factor in obtaining information about the outside world, it is necessary to provide a sufficient level of illumination in the room. Its regulation is carried out in accordance with SNiP, which for solar radiation are compiled taking into account the light and climatic features of various geographical zones and are taken into account in the design and construction of various facilities.

Even a superficial analysis of the electromagnetic spectrum of solar radiation proves how great the influence of this type of radiation on the human body.

Distribution of solar radiation over the territory of the Earth

Not all radiation coming from the Sun reaches the earth's surface. And there are many reasons for this. The earth steadfastly repels the attack of those rays that are detrimental to its biosphere. This function is performed by the ozone shield of our planet, preventing the most aggressive part of ultraviolet radiation from passing through. Atmospheric filter in the form of water vapor, carbon dioxide, dust particles suspended in the air - largely reflects, scatters and absorbs solar radiation.

That part of it that has overcome all these obstacles falls to the surface of the earth at different angles, depending on the latitude of the area. The life-giving solar heat is distributed unevenly over the territory of our planet. As the height of the sun changes during the year, the mass of air above the horizon changes, through which the path of the sun's rays lies. All this affects the distribution of the intensity of solar radiation over the planet. The general trend is this - this parameter increases from the pole to the equator, since the greater the angle of incidence of the rays, the more heat enters per unit area.

Solar radiation maps allow you to have a picture of the distribution of solar radiation intensity over the territory of the Earth.

The influence of solar radiation on the Earth's climate

The infrared component of solar radiation has a decisive influence on the Earth's climate.

It is clear that this occurs only at a time when the Sun is above the horizon. This influence depends on the distance of our planet from the Sun, which changes during the year. The Earth's orbit is an ellipse, inside which is the Sun. Making its annual journey around the Sun, the Earth moves away from its luminary, then approaches it.

In addition to changing the distance, the amount of radiation entering the earth is determined by the inclination of the earth's axis to the plane of the orbit (66.5 °) and the change of seasons caused by it. It is more in summer than in winter. At the equator, this factor is absent, but as the latitude of the observation site increases, the gap between summer and winter becomes significant.

All sorts of cataclysms take place in the processes taking place on the Sun. Their impact is partly offset by vast distances, the protective properties of the earth's atmosphere and the earth's magnetic field.

How to protect yourself from solar radiation

The infrared component of solar radiation is the coveted warmth that the inhabitants of the middle and northern latitudes look forward to all other seasons of the year. Solar radiation as a healing factor is used by both healthy and sick people.

However, we must not forget that heat, like ultraviolet, is a very strong irritant. Abuse of their action can lead to burns, general overheating of the body, and even exacerbation of chronic diseases. When sunbathing, you should follow the rules tested by life. You should be especially careful when sunbathing on clear sunny days. Infants and the elderly, patients with chronic tuberculosis and problems with the cardiovascular system, should be content with diffused solar radiation in the shade. This ultraviolet is quite enough to meet the needs of the body.

Even young people who do not have special health problems should be protected from solar radiation.

Now there is a movement whose activists oppose tanning. And not in vain. Tanned skin is undeniably beautiful. But the melanin produced by the body (what we call sunburn) is its protective reaction to the effects of solar radiation. No sunburn benefits! There is even evidence that sunburn shortens life, since radiation has a cumulative property - it accumulates throughout life.

If the situation is so serious, you should scrupulously follow the rules prescribing how to protect yourself from solar radiation:

• strictly limit the time for sunbathing and do it only during safe hours;
• when in the active sun, you should wear a wide-brimmed hat, closed clothes, sunglasses and an umbrella;
• Use only high quality sunscreen.

Is solar radiation dangerous to humans at all times of the year? The amount of solar radiation reaching the earth is associated with the change of seasons. At mid-latitudes in summer it is 25% more than in winter. At the equator, this difference does not exist, but as the latitude of the place of observation increases, this difference increases. This is due to the fact that our planet is tilted at an angle of 23.3 degrees with respect to the sun. In winter, it is low above the horizon and illuminates the earth only with gliding rays, which warm the illuminated surface less. This position of the rays causes their distribution over a larger surface, which reduces their intensity compared to the summer sheer fall. In addition, the presence of an acute angle during the passage of rays through the atmosphere, "lengthens" their path, forcing them to lose more heat. This circumstance reduces the impact of solar radiation in winter.

The sun is a star that is a source of heat and light for our planet. It "governs" the climate, the change of seasons and the state of the entire biosphere of the Earth. And only knowledge of the laws of this powerful influence will allow using this life-giving gift for the benefit of people's health.

The sun is a source of heat and light, giving strength and health. However, its impact is not always positive. Lack of energy or its excess can upset the natural processes of life and provoke various problems. Many people believe that tanned skin looks much more beautiful than pale, but if you spend a long time under direct rays, you can get a severe burn. Solar radiation is a stream of incoming energy propagating in the form of electromagnetic waves passing through the atmosphere. It is measured by the power of the energy transferred by it per unit surface area (watt / m 2). Knowing how the sun affects a person, you can prevent its negative impact.

What is solar radiation

Many books have been written about the Sun and its energy. The sun is the main source of energy for all physical and geographical phenomena on Earth. One two-billionth of the light penetrates into the upper layers of the planet's atmosphere, while the greater part settles in world space.

Rays of light are the primary sources of other types of energy. Getting on the surface of the earth and into the water, they form into heat, affect climatic features and weather.

The degree of exposure to light rays on a person depends on the level of radiation, as well as the period spent under the sun. People use many types of waves to their advantage, using x-rays, infrared rays, and ultraviolet light. However, solar waves in their pure form in large quantities can adversely affect human health.

The amount of radiation depends on:

• position of the sun. The greatest amount of exposure occurs in the plains and deserts, where the solstice is quite high and the weather is cloudless. The polar regions receive the minimum amount of light, since cloud cover absorbs a significant part of the light flux;
• day length. The closer to the equator, the longer the day. It is there that people get more heat;
• atmospheric properties: cloudiness and humidity. At the equator, increased cloudiness and humidity, which is an obstacle to the passage of light. That is why the amount of light flux there is less than in tropical zones.

Distribution

The distribution of sunlight over the earth's surface is uneven and depends on:

• density and humidity of the atmosphere. The larger they are, the less exposure;
• geographic latitude of the area. The amount of light received rises from the poles to the equator;
• the movements of the earth. The amount of radiation varies depending on the time of year;
• characteristics of the earth's surface. A large amount of light flux is reflected in light surfaces, such as snow. Chernozem reflects the light energy most weakly.

Due to the extent of its territory, the level of radiation in Russia varies considerably. Solar exposure in the northern regions is approximately the same - 810 kWh / m 2 for 365 days, in the south - more than 4100 kWh / m 2.

Of no small importance is the length of hours during which the sun shines.. These indicators are diverse in different regions, which is influenced not only by geographical latitude, but also by the presence of mountains. On the solar radiation map of Russia, it is clearly seen that in some regions it is not advisable to install power lines, since natural light is quite capable of meeting the needs of residents in electricity and heat.

Kinds

Light streams reach the Earth in various ways. It is on this that the types of solar radiation depend:

• The rays from the sun are called direct radiation.. Their strength depends on the height of the sun above the horizon. The maximum level is observed at 12 noon, the minimum - in the morning and evening. In addition, the impact intensity is related to the time of year: the highest occurs in summer, the lowest in winter. It is characteristic that in the mountains the level of radiation is higher than on flat surfaces. Also, dirty air reduces direct light fluxes. The lower the sun above the horizon, the less ultraviolet.
• Reflected radiation is radiation that is reflected by water or the surface of the earth.
• Scattered solar radiation is formed when the light flux is scattered. The blue color of the sky in cloudless weather depends on it.

Absorbed solar radiation depends on the reflectivity of the earth's surface - albedo.

The spectral composition of radiation is diverse:

• colored or visible rays give illumination and are of great importance in the life of plants;
• ultraviolet should penetrate the human body moderately, since its excess or lack can be harmful;
• infrared irradiation gives a feeling of warmth and affects the growth of vegetation.

Total solar radiation is direct and scattered rays penetrating the earth.. In the absence of cloudiness, at about 12 noon, and also in the summer, it reaches its maximum.

Stories from our readers

Vladimir
61 years old

How does the impact

Electromagnetic waves are made up of different parts. There are invisible, infrared and visible, ultraviolet rays. Characteristically, radiation fluxes have a different energy structure and affect people in different ways.

The light flux can have a beneficial, healing effect on the condition of the human body. Passing through the visual organs, light regulates metabolism, sleep patterns, and affects the general well-being of a person. In addition, light energy can cause a feeling of warmth. When the skin is irradiated, photochemical reactions occur in the body that contribute to the proper metabolism.

Ultraviolet has a high biological ability, having a wavelength of 290 to 315 nm. These waves synthesize vitamin D in the body, and are also capable of destroying the tuberculosis virus in a few minutes, staphylococcus - within a quarter of an hour, typhoid fever bacilli - in 1 hour.

Characteristically, cloudless weather reduces the duration of emerging epidemics of influenza and other diseases, such as diphtheria, which have the ability to be transmitted by airborne droplets.

The natural forces of the body protect a person from sudden atmospheric fluctuations: air temperature, humidity, pressure. However, sometimes such protection is weakened, which, under the influence of high humidity, together with elevated temperatures, leads to thermal shock.

Exposure to radiation is related to the degree of its penetration into the body. The longer the wavelength, the stronger the radiation. Infrared waves are able to penetrate up to 23 cm under the skin, visible streams - up to 1 cm, ultraviolet - up to 0.5-1 mm.

People receive all types of rays during the activity of the sun, when they stay in open spaces. Light waves allow a person to adapt to the world, which is why in order to ensure comfortable well-being in rooms, it is necessary to create conditions for an optimal level of lighting.

Human impact

The impact of solar radiation on human health is determined by various factors. The place of residence of a person, the climate, as well as the amount of time spent under direct rays matter.

With a lack of sun, residents of the Far North, as well as people whose activities are related to working underground, for example, miners, experience various life disorders, bone strength decreases, and nervous disorders occur.

Children who receive less light suffer from rickets more often than others. In addition, they are more susceptible to dental diseases, and also have a longer course of tuberculosis.

However, too long exposure to light waves without a periodic change of day and night can be detrimental to health. For example, residents of the Arctic often suffer from irritability, fatigue, insomnia, depression, and decreased ability to work.

Radiation in the Russian Federation is less active than, for example, in Australia.

Thus, people who are under long-term radiation:

• are at high risk of developing skin cancer;
• have an increased tendency to dry skin, which in turn accelerates the aging process and the appearance of pigmentation and early wrinkles;
• may suffer from visual impairment, cataracts, conjunctivitis;
• have a weakened immune system.

Lack of vitamin D in humans is one of the causes of malignant neoplasms, metabolic disorders, which leads to overweight, endocrine disorders, sleep disturbances, physical exhaustion, bad mood.

A person who systematically receives the light of the sun and does not abuse sunbathing, as a rule, does not experience health problems:

• has a stable work of the heart and blood vessels;
• does not suffer from nervous diseases;
• has a good mood;
• has a normal metabolism;
• rarely gets sick.

Thus, only a dosed intake of radiation can positively affect human health.

How to protect yourself

An excess of radiation can provoke overheating of the body, burns, as well as exacerbation of some chronic diseases.. Fans of sunbathing need to take care of the implementation of simple rules:

• sunbathe in open spaces with caution;
• during hot weather, hide in the shade under scattered rays. This is especially true for young children and older people with tuberculosis and heart disease.

It should be remembered that it is necessary to sunbathe at a safe time of day, and also not to be under the scorching sun for a long time. In addition, it is worth protecting your head from heatstroke by wearing a hat, sunglasses, closed clothing, and using various sunscreens.

Solar radiation in medicine

Light fluxes are actively used in medicine:

• X-rays use the ability of waves to pass through soft tissues and the skeletal system;
• the introduction of isotopes allows you to fix their concentration in the internal organs, to detect many pathologies and foci of inflammation;
• radiation therapy can destroy the growth and development of malignant neoplasms.

The properties of waves are successfully used in many physiotherapy devices:

• Devices with infrared radiation are used for heat treatment of internal inflammatory processes, bone diseases, osteochondrosis, rheumatism, due to the ability of waves to restore cellular structures.
• Ultraviolet rays can adversely affect living beings, inhibit plant growth, suppress microorganisms and viruses.

The hygienic value of solar radiation is great. Devices with ultraviolet radiation are used in therapy:

• various injuries of the skin: wounds, burns;
• infections;
• diseases of the oral cavity;
• oncological neoplasms.

In addition, radiation has a positive effect on the human body as a whole: it can give strength, strengthen the immune system, and compensate for the lack of vitamins.

Sunlight is an important source of full human life. Sufficient intake of it leads to a favorable existence of all living beings on the planet. A person cannot reduce the degree of radiation, but he can protect himself from its negative effects.

SOLAR RADIATION