Proverbs and sayings about May HORIZONTALLY: 2. May will deceive - in ... will leave.4 ....
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SOLAR RADIATION
SOLAR RADIATION- electromagnetic and corpuscular radiation of the Sun. Electromagnetic radiation propagates in the form electromagnetic waves at the speed of light and penetrates the earth's atmosphere. Solar radiation reaches the earth's surface in the form of direct and diffuse radiation.
Solar radiation is the main source of energy for all physical and geographical processes occurring on the earth's surface and in the atmosphere (see Insolation). Solar radiation is usually measured by its thermal effect and is expressed in calories per unit area per unit of time. In total, the Earth receives from the Sun less than one two-billionth of its radiation.
The spectral range of the Sun's electromagnetic radiation is very wide - from radio waves to X-rays - however, its maximum intensity falls on the visible (yellow-green) part of the spectrum.
There is also a corpuscular part of solar radiation, consisting mainly of protons moving from the Sun at speeds of 300-1500 km/s (solar wind). During solar flares, high-energy particles (mainly protons and electrons) are also formed, which form the solar component of cosmic rays.
The energy contribution of the corpuscular component of solar radiation to its total intensity is small compared to the electromagnetic one. Therefore, in a number of applications, the term "solar radiation" is used in a narrow sense, meaning only its electromagnetic part.
The amount of solar radiation depends on the height of the sun, the time of year, and the transparency of the atmosphere. 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.
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. However, in winter in the same places, the Sun does not rise above the horizon at all, and therefore does not affect the region. Solar radiation is not blocked by clouds, and therefore it still enters the Earth (when the Sun is directly above the horizon). Solar radiation is a combination of the bright yellow color of the Sun and heat, heat also passes through clouds. Solar radiation is transmitted to Earth through radiation, and not through heat conduction.
The amount of radiation received by a celestial body depends on the distance between the planet and the star - as the distance doubles, the amount of radiation coming from the star to the planet decreases by a factor of four (proportional 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 eccentricity of the Earth's orbit is also not constant - over the course of millennia, it changes, periodically forming an almost perfect circle, sometimes the eccentricity reaches 5% (currently it is 1.67%), that is, at perihelion, the Earth currently receives 1.033 more solar radiation than in aphelion, and with the greatest eccentricity - more than 1.1 times. However, the amount of incoming solar radiation much more strongly depends on the change of seasons - at present, the total amount of solar radiation entering the Earth remains practically unchanged, but at latitudes of 65 N.Sh (the latitude of the 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 with respect 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 there is no difference between winter and summer at the equator. Beyond the Arctic Circle, in summer, the influx of solar radiation is very high, and in winter it is very small. This forms the climate on Earth. In addition, periodic changes in the eccentricity of the Earth's orbit can lead to the emergence of different geological epochs: for example,
The bright luminary burns us with hot rays and makes us think about the significance of radiation in our life, its benefits and harms. What is solar radiation? Lesson school physics invites us to start to get acquainted with the concept of electromagnetic radiation in general. This term refers to another form of matter - different from matter. This includes both visible light and the spectrum that is not perceived by the eye. That is, x-rays, gamma rays, ultraviolet and infrared.
In the presence of a source-emitter of radiation, its electromagnetic waves propagate in all directions at the speed of light. These waves, like any other, have certain characteristics. These include the oscillation frequency and wavelength. Any body whose temperature differs from absolute zero has the property to emit radiation.
The sun is the main and most powerful source of radiation near our planet. In turn, the Earth (its atmosphere and surface) itself emits radiation, but in a different range. Observation of the temperature conditions on the planet over long periods of time gave rise to a hypothesis about the balance of the amount of heat received from the Sun and given off into outer space.
The vast majority (about 99%) of the solar energy in the spectrum lies in the wavelength range from 0.1 to 4 microns. The remaining 1% is longer and shorter rays, including radio waves and x-rays. About half of the radiant energy of the sun falls on the spectrum that we perceive with our eyes, approximately 44% - in infrared radiation, 9% - in ultraviolet. How do we know how solar radiation is divided? The calculation of its distribution is possible thanks to research from space satellites.
There are substances that can enter a special state and emit additional radiation of a different wave range. For example, there is a glow at low temperatures that are not characteristic of the emission of light by a given substance. This type of radiation, called luminescent, does not lend itself to the usual principles of thermal radiation.
The phenomenon of luminescence occurs after the absorption of a certain amount of energy by the substance and the transition to another state (the so-called excited state), which is higher in energy than at the substance's own temperature. Luminescence appears during the reverse transition - from an excited to a familiar state. In nature, we can observe it in the form of night sky glows and aurora.
Energy sun rays- almost the only source of heat for our planet. Its own radiation, coming from its depths to the surface, has an intensity that is about 5 thousand times less. At the same time, visible light - one of the most important factors of life on the planet - is only a part of solar radiation.
The energy of the sun's rays is converted into heat by a smaller part - in the atmosphere, a larger one - on the surface of the Earth. There it is spent on heating water and soil (upper layers), which then give off heat to the air. Being heated, the atmosphere and the earth's surface, in turn, emit infrared rays into space, while cooling.
The radiation that comes to the surface of our planet directly from the solar disk is commonly referred to as direct solar radiation. The sun spreads it in all directions. Taking into account the huge distance from the Earth to the Sun, direct solar radiation at any point on the earth's surface can be represented as a beam of parallel rays, the source of which is practically in infinity. The area located perpendicular to the rays of sunlight thus receives the greatest amount of it.
Radiation flux density (or irradiance) is a measure of the amount of radiation incident on a particular surface. This is the amount of radiant energy falling per unit time per unit area. This value is measured - energy illumination - in W / m 2. Our Earth, as everyone knows, revolves around the Sun in an ellipsoidal orbit. The sun is at one of the foci of this ellipse. Therefore, every year certain time(early January) the Earth occupies a position closest to the Sun and in another (early July) - farthest from it. In this case, the magnitude of the energy illumination varies in inverse proportion with respect to the square of the distance to the luminary.
Where does the solar radiation that reaches the Earth go? Its types are determined by many factors. Depending on the geographic latitude, humidity, cloudiness, part of it is dissipated in the atmosphere, part is absorbed, but most still reaches the surface of the planet. In this case, a small amount is reflected, and the main one is absorbed by the earth's surface, under the influence of which it is heated. Scattered solar radiation also partially falls on the earth's surface, is partially absorbed by it and partially reflected. The rest of it goes into outer space.
Is solar radiation homogeneous? Its types after all "losses" in the atmosphere can differ in their spectral composition. After all, rays with different lengths are scattered and absorbed differently. On average, about 23% of its initial amount is absorbed by the atmosphere. Approximately 26% of the total flux is converted into diffuse radiation, 2/3 of which then falls on the Earth. In essence, this is a different type of radiation, different from the original. Scattered radiation is sent to Earth not by the disk of the Sun, but by the vault of heaven. It has a different spectral composition.
Absorbs radiation mainly ozone - the visible spectrum, and ultraviolet rays. Infrared radiation is absorbed by carbon dioxide (carbon dioxide), which, by the way, is very small in the atmosphere.
Scattering of radiation, weakening it, occurs for any wavelength of the spectrum. In the process, its particles, falling under electromagnetic influence, redistribute the energy of the incident wave in all directions. That is, the particles serve as point sources of energy.
Due to scattering, the light coming from the sun changes color when passing through the layers of the atmosphere. Practical value scattering - in the creation of daylight. If the Earth were devoid of an atmosphere, illumination would exist only in places where direct or reflected rays of the sun hit the surface. That is, the atmosphere is the source of illumination during the day. Thanks to it, it is light both in places inaccessible to direct rays, and when the sun is hidden behind clouds. It is scattering that gives color to the air - we see the sky blue.
What else influences solar radiation? The turbidity factor should not be discounted either. After all, the weakening of radiation occurs in two ways - the atmosphere itself and water vapor, as well as various impurities. The level of dust increases in summer (as does the content of water vapor in the atmosphere).
It refers to the total amount of radiation falling on the earth's surface, both direct and diffuse. The total solar radiation decreases in cloudy weather.
For this reason, in summer, the total radiation is on average higher before noon than after it. And in the first half of the year - more than in the second.
What happens to the total radiation on the earth's surface? Getting there, it is mostly absorbed by the upper layer of soil or water and turns into heat, part of it is reflected. The degree of reflection depends on the nature of the earth's surface. The indicator expressing the percentage of reflected solar radiation to its total amount falling on the surface is called the surface albedo.
The concept of self-radiation of the earth's surface is understood as long-wave radiation emitted by vegetation, snow cover, upper layers of water and soil. The radiation balance of a surface is the difference between its amount absorbed and emitted.
It is proved that the counter radiation is almost always less than the terrestrial one. Because of this, the surface of the earth bears heat losses. The difference between the intrinsic radiation of the surface and the atmospheric radiation is called the effective radiation. This is actually a net loss of energy and, as a result, heat at night.
It also exists during the daytime. But during the day it is partially compensated or even blocked by absorbed radiation. Therefore, the surface of the earth is warmer during the day than at night.
Solar radiation on Earth is unevenly distributed throughout the year. Its distribution has a zonal character, and the isolines (connecting points of equal values) of the radiation flux are by no means identical to the latitudinal circles. This discrepancy is caused by different levels of cloudiness and transparency of the atmosphere in different regions of the globe.
The total solar radiation during the year has the greatest value in subtropical deserts with a low-cloud atmosphere. It is much less in the forest regions of the equatorial belt. The reason for this is increased cloudiness. This indicator decreases towards both poles. But in the region of the poles it increases again - in the northern hemisphere it is less, in the region of snowy and slightly cloudy Antarctica - more. Above the surface of the oceans, on average, solar radiation is less than over the continents.
Almost everywhere on Earth, the surface has a positive radiation balance, that is, for the same time, the influx of radiation is greater than the effective radiation. The exceptions are the regions of Antarctica and Greenland with their ice plateaus.
But the above does not mean the annual warming of the earth's surface. The excess of absorbed radiation is compensated by heat leakage from the surface into the atmosphere, which occurs when the water phase changes (evaporation, condensation in the form of clouds).
Thus, there is no radiation equilibrium as such on the Earth's surface. But there is a thermal equilibrium - the inflow and loss of heat is balanced in different ways, including radiation.
In the same latitudes of the globe, the radiation balance is greater on the surface of the ocean than over land. This can be explained by the fact that the layer that absorbs radiation in the oceans is thicker, while at the same time, the effective radiation there is less due to the cold of the sea surface compared to land.
Significant fluctuations in the amplitude of its distribution are observed in deserts. The balance is lower there due to the high effective radiation in dry air and low cloud cover. To a lesser extent, it is lowered in areas of monsoon climate. In the warm season, the cloudiness there is increased, and the absorbed solar radiation is less than in other regions of the same latitude.
Of course, main factor, on which the average annual solar radiation depends, is the latitude of a particular area. Record "portions" of ultraviolet go to countries located near the equator. This is Northeast Africa, its eastern coast, the Arabian Peninsula, the north and west of Australia, part of the islands of Indonesia, the western coast of South America.
In Europe, Turkey, the south of Spain, Sicily, Sardinia, the islands of Greece, the coast of France (southern part), as well as part of the regions of Italy, Cyprus and Crete take on the largest dose of both light and radiation.
Solar total radiation in Russia is distributed, at first glance, unexpectedly. On the territory of our country, oddly enough, not at all Black Sea resorts hold the palm. The largest doses of solar radiation fall on the territories bordering China and Severnaya Zemlya. In general, solar radiation in Russia is not particularly intense, which is fully explained by our northern geographic location. The minimum amount of sunlight goes to the northwestern region - St. Petersburg, together with the surrounding areas.
Solar radiation in Russia is inferior to Ukraine. There, the most ultraviolet radiation goes to the Crimea and territories beyond the Danube, in second place are the Carpathians with the southern regions of Ukraine.
The total (it includes both direct and scattered) solar radiation falling on a horizontal surface is given by months in specially designed tables for different territories and is measured in MJ / m 2. For example, solar radiation in Moscow ranges from 31-58 in the winter months to 568-615 in the summer.
Insolation, or the amount of useful radiation falling on a surface illuminated by the sun, varies greatly in different geographic locations. Annual insolation is calculated per square meter in megawatts. For example, in Moscow this value is 1.01, in Arkhangelsk - 0.85, in Astrakhan - 1.38 MW.
When determining it, it is necessary to take into account such factors as the time of year (in winter, the illumination and longitude of the day are lower), the nature of the terrain (mountains can block the sun), characteristic of the area weather- fog, frequent rains and cloudiness. The light-receiving plane can be oriented vertically, horizontally or obliquely. The amount of insolation, as well as the distribution of solar radiation in Russia, is a data grouped in a table by city and region, indicating the geographical latitude.
General hygiene. Solar radiation and its hygienic significance.
By solar radiation, we mean the entire radiation flux emitted by the Sun, which is electromagnetic oscillations of various wavelengths. From a hygienic point of view, of particular interest is the opric part of sunlight, which occupies the range from 280-2800 nm. Longer waves are radio waves, shorter ones are gamma rays, ionizing radiation does not reach the Earth's surface, because it is retained in the upper layers of the atmosphere, in the ozone layer in particular. Ozone is distributed throughout the atmosphere, but at an altitude of about 35 km forms the ozone layer.
The intensity of solar radiation depends primarily on the height of the sun above the horizon. If the sun is at its zenith, then the path that the sun's rays travel will be much shorter than their path if the sun is near the horizon. By increasing the path, the intensity of solar radiation changes. The intensity of solar radiation also depends on the angle at which the sun's rays fall, the illuminated area also depends on this (with an increase in the angle of incidence, the illumination area increases). Thus, the same solar radiation falls on a large surface, so the intensity decreases. The intensity of solar radiation depends on the mass of air through which the sun's rays pass. The intensity of solar radiation in the mountains will be higher than above sea level, because the layer of air through which the sun's rays pass will be less than above sea level. Of particular importance is the impact on the intensity of solar radiation the state of the atmosphere, its pollution. If the atmosphere is polluted, then the intensity of solar radiation decreases (in the city, the intensity of solar radiation is on average 12% less than in rural areas). The voltage of solar radiation has a daily and annual background, that is, the voltage of solar radiation changes during the day, and also depends on the time of year. The greatest intensity of solar radiation is observed in summer, the smallest - in winter. In terms of its biological effect, solar radiation is heterogeneous: it turns out that each wavelength has different action on the human body. In this regard, the solar spectrum is conditionally divided into 3 sections:
1. ultraviolet rays, from 280 to 400 nm
2. visible spectrum from 400 to 760 nm
3. infrared rays from 760 to 2800 nm.
With daily and annual solar radiation, the composition and intensity of individual spectra undergo changes. The greatest changes are exposed to the rays of the UV spectrum.
We estimate the intensity of solar radiation based on the so-called solar constant. The solar constant is the amount of solar energy received per unit time per unit area located on the upper boundary of the atmosphere at right angles to the sun's rays at the average distance of the Earth from the Sun. This solar constant is measured by satellite and is equal to 1.94 calories/cm2
in min. Passing through the atmosphere, the sun's rays are significantly weakened - scattered, reflected, absorbed. On average, with a clean atmosphere on the Earth's surface, the intensity of solar radiation is 1.43 - 1.53 calories / cm2 per minute.The intensity of the sun's rays at noon in May in Yalta is 1.33, in Moscow 1.28, in Irkutsk 1.30, in Tashkent 1.34.
The biological significance of the visible part of the spectrum.
The visible part of the spectrum is a specific stimulus of the organ of vision. Light is a necessary condition for the functioning of the eye, the most subtle and sensitive sense organ. Light provides approximately 80% of information about the outside world. This is the specific action visible light, but also the general biological effect of visible light: it stimulates the vital activity of the body, enhances metabolism, improves overall well-being, affects the psycho-emotional sphere, and increases working capacity. Light heals environment. With a lack of natural vision, changes occur on the part of the organ of vision. Fatigue sets in quickly, efficiency decreases, and industrial injuries increase. The body is affected not only by illumination, but also by different colors has a different effect on the psycho-emotional state. The best work performance was obtained under yellow and white illumination. Psychologically, colors act opposite to each other. 2 groups of colors were formed in connection with this:
1) warm colors - yellow, orange, red. 2) cold tones - blue, blue, violet. Cold and warm tones have different physiological effects on the body. Warm tones increase muscle tension, increase blood pressure, and increase the rhythm of breathing. Cold tones, on the contrary, lower blood pressure, slow down the rhythm of the heart and breathing. This is often used in practice: for patients with high fever, purple-colored wards are most suitable, dark ocher improves the well-being of patients with low blood pressure. Red increases appetite. Moreover, the effectiveness of drugs can be increased by changing the color of the pill. Patients suffering from depressive disorders were given the same medicine in tablets of different colors: red, yellow, green. The best results were brought by treatment with yellow tablets.
Color is used as a carrier of coded information, for example in production to indicate danger. There is a generally accepted standard for signal and identification color: green - water, red - steam, yellow - gas, orange - acids, violet - alkalis, brown - combustible liquids and oils, blue - air, gray - other.
From a hygienic point of view, the assessment of the visible part of the spectrum is carried out according to the following indicators: natural and artificial lighting are separately assessed. Natural lighting is evaluated according to 2 groups of indicators: physical and lighting. The first group includes:
1. light coefficient - characterizes the ratio of the area of the glazed surface of windows to the area of the floor.
2. Angle of incidence - characterizes the angle at which the rays fall. As a rule, the minimum angle of incidence should be at least 270.
3. Angle of the opening-- characterizes the illumination of the heavenly light (should be at least 50). On the first floors of Leningrad houses - wells, this corner is actually absent.
4. The depth of the room is the ratio of the distance from the top edge of the window to the floor to the depth of the room (the distance from the outer to the inner wall).
Lighting indicators are indicators determined using a device - a luxmeter. Absolute and relative illuminance is measured. Absolute illumination is the illumination on the street. The illuminance coefficient (KEO) is defined as the ratio of relative illuminance (measured as the ratio of relative illuminance (measured in the room) to absolute illuminance, expressed in %. The illuminance in the room is measured at the workplace. The principle of operation of the luxmeter is that the device has a sensitive photocell (selenium - since selenium is close in sensitivity to the human eye.) Approximate illumination on the street can be found using the graph of the light climate.
To assess the artificial lighting of premises, the value of brightness, lack of pulsations, color, etc.
infrared rays. Main biological action of these rays is thermal, and this action also depends on the wavelength. Short rays carry more energy, so they penetrate into the depths and have a strong thermal effect. The long section exerts its thermal effect on the surface. This is used in physiotherapy to warm up areas at different depths.
In order to evaluate the measurement of infrared rays, there is a device - an actinometer. Infrared radiation is measured in calories per cm2/min. The adverse effect of infrared rays is observed in hot shops, where they can lead to occupational diseases - cataracts (clouding of the lens). Cataracts are caused by short infrared rays. A measure of prevention is the use of goggles, overalls.
Features of the effect of infrared rays on the skin: a burn occurs - erythema. It occurs due to thermal expansion of blood vessels. Its peculiarity lies in the fact that it has different boundaries, it arises immediately.
In connection with the action of infrared rays, 2 conditions of the body can occur: heat stroke and sunstroke. Sunstroke is the result of direct exposure to sunlight on the human body, mainly with damage to the central nervous system. Sunstroke affects those who spend many hours in a row under the scorching rays of the sun with their heads uncovered. There is a heating of the meninges.
Heat stroke occurs when the body overheats. It can happen to those who do hard physical work in a hot room or in hot weather. Heat strokes were especially characteristic of our servicemen in Afghanistan.
In addition to actinometers for measuring infrared radiation, there are various types of pyrometers. The action is based on the absorption of radiant energy by the black body. The receptive layer consists of blackened and white plates, which, depending on infrared radiation, heat up differently. There is a current on the thermopile and the intensity of infrared radiation is recorded. Since the intensity of infrared radiation is important in production conditions, there are norms for infrared radiation for hot shops in order to avoid adverse effects on the human body, for example, in a pipe rolling shop, narma is 1.26 - 7.56, iron smelting is 12.25. Radiation levels exceeding 3.7 are considered significant and require preventive measures - the use of protective screens, water curtains, overalls.
Ultraviolet rays (UV).
This is the most biologically active part of the solar spectrum. She is also heterogeneous. In this regard, a distinction is made between long-wave and short-wave UV. UV promotes tanning. When UV enters the skin, 2 groups of substances are formed in it: 1) specific substances, these include vitamin D, 2) non-specific substances - histamine, acetylcholine, adenosine, that is, these are protein breakdown products. Tanning or erythemal action is reduced to a photochemical effect - histamine and other biologically active substances contribute to vasodilation. The peculiarity of this erythema is that it does not occur immediately. Erythema has clearly defined boundaries. UV erythema always results in a more or less pronounced tan, depending on the amount of pigment in the skin. The mechanism of tanning action is still not well understood. It is believed that erythema first occurs, nonspecific substances such as histamine are released, the body converts the products of tissue decay into melanin, as a result of which the skin acquires a peculiar shade. Sunburn, therefore, is a test of the protective properties of the body (a sick person does not tan, tans slowly).
The most favorable tanning occurs under the influence of UV light with a wavelength of approximately 320 nm, that is, when exposed to the long-wave part of the UV spectrum. In the south, short-wave UFL prevails, and in the north, long-wave UFL. Shortwave rays are the most susceptible to scattering. And dispersion is best in a clean atmosphere and in the northern region. Thus, the most useful tan in the north is longer, darker. UVB is a very powerful factor in the prevention of rickets. With a lack of UV radiation, rickets develops in children, and osteoporosis or osteomalacia in adults. Usually encountered in the Far North or groups of workers working underground. In the Leningrad region, from mid-November to mid-February, the UV part of the spectrum is practically absent, which contributes to the development of solar starvation. To prevent sun starvation, artificial tanning is used. Light starvation is a prolonged absence of the UV spectrum. Under the action of UV in the air, ozone is formed, the concentration of which must be controlled.
UV light has a bactericidal effect. It is used to disinfect large wards, food products, water.
The intensity of UV radiation is determined by the photochemical method by the amount decomposed under the action of UV oxalic acid in quartz test tubes (ordinary glass does not pass UFL). The intensity of UV radiation is also determined by an ultravioletmeter. For medical purposes, ultraviolet light is measured in biodoses.
Solar radiation is the radiation inherent in the luminary of our planetary system. The Sun is the main star around which the Earth revolves, as well as neighboring planets. In fact, this is a huge hot gas ball, constantly emitting energy flows into the space around it. This is what they call radiation. Deadly, at the same time it is this energy - one of the main factors that make life possible on our planet. Like everything in this world, the benefits and harms of solar radiation for organic life are closely interrelated.
To understand what solar radiation is, you must first understand what the Sun is. The main source of heat, which provides the conditions for organic existence on our planet, in the universal spaces is only a small star on the galactic outskirts of the Milky Way. But for earthlings, the Sun is the center of a mini-universe. After all, it is around this gas clot that our planet revolves. The sun gives us heat and light, that is, it supplies forms of energy without which our existence would be impossible.
In ancient times, the source of solar radiation - the Sun - was a deity, an object worthy of worship. The solar trajectory across the sky seemed to people an obvious proof of God's will. Attempts to delve into the essence of the phenomenon, to explain what this luminary is, have been made for a long time, and Copernicus made a particularly significant contribution to them, having formed the idea of heliocentrism, which was strikingly different from the geocentrism generally accepted in that era. However, it is known for certain that even in ancient times, scientists more than once thought about what the Sun is, why it is so important for any life forms on our planet, why the movement of this luminary is exactly the way we see it.
The progress of technology has made it possible to better understand what the Sun is, what processes take place inside the star, on its surface. Scientists have learned what solar radiation is, how a gas object affects the planets in its zone of influence, in particular, the earth's climate. Now humanity has a sufficiently voluminous knowledge base to say with confidence: it was possible to find out what the radiation emitted by the Sun is, how to measure this energy flow and how to formulate the features of its effect on different forms organic life on earth.
Most important step in mastering the essence of the concept was made in the last century. It was then that the eminent astronomer A. Eddington formulated an assumption: in the solar depths, thermonuclear fusion, which allows a huge amount of energy to be released into the space around the star. Trying to estimate the amount of solar radiation, efforts were made to determine the actual parameters of the environment on the star. Thus, the core temperature, according to scientists, reaches 15 million degrees. This is sufficient to cope with the mutual repulsive influence of protons. The collision of units leads to the formation of helium nuclei.
New information attracted the attention of many prominent scientists, including A. Einstein. In an attempt to estimate the amount of solar radiation, scientists have found that helium nuclei are inferior in mass to the total value of 4 protons needed to form new structure. Thus, a feature of the reactions, called the "mass defect", was revealed. But in nature, nothing can disappear without a trace! In an attempt to find "escaped" quantities, scientists compared the energy recovery and the specifics of the change in mass. It was then that it was possible to reveal that the difference is emitted by gamma quanta.
The radiated objects make their way from the core of our star to its surface through numerous gaseous atmospheric layers, which leads to the fragmentation of elements and the formation of electromagnetic radiation on their basis. Among other types of solar radiation is the light perceived by the human eye. Approximate estimates suggested that the process of passage of gamma rays takes about 10 million years. Another eight minutes - and the radiated energy reaches the surface of our planet.
Solar radiation is called the total complex of electromagnetic radiation, which is characterized by a fairly wide range. This includes the so-called solar wind, that is, the energy flow formed by electrons, light particles. At the boundary layer of the atmosphere of our planet, the same intensity of solar radiation is constantly observed. The energy of a star is discrete, its transfer is carried out through quanta, while the corpuscular nuance is so insignificant that one can consider the rays as electromagnetic waves. And their distribution, as physicists have found out, occurs evenly and in a straight line. Thus, in order to describe solar radiation, it is necessary to determine its characteristic wavelength. Based on this parameter, it is customary to distinguish several types of radiation:
The ratio of infrared, visible, ultraviolet best is estimated as follows: 52%, 43%, 5%.
For a quantitative radiation assessment, it is necessary to calculate the energy flux density, that is, the amount of energy that reaches a limited area of the surface in a given time period.
Studies have shown that solar radiation is mainly absorbed by the planetary atmosphere. Due to this, heating occurs to a temperature comfortable for organic life, characteristic of the Earth. The existing ozone shell allows only one hundredth of the ultraviolet radiation to pass through. At the same time, short wavelengths that are dangerous to living beings are completely blocked. Atmospheric layers are able to scatter almost a third of the sun's rays, another 20% are absorbed. Consequently, no more than half of all energy reaches the surface of the planet. It is this "residue" in science that is called direct solar radiation.
Several aspects are known that determine how intense direct radiation will be. The most significant are the angle of incidence, which depends on latitude (a geographical characteristic of the terrain on the globe), the time of year, which determines how great the distance to a particular point from the radiation source is. Much depends on the characteristics of the atmosphere - how polluted it is, how many clouds there are at a given moment. Finally, the nature of the surface on which the beam falls, namely, its ability to reflect the incoming waves, plays a role.
Total solar radiation is a value that combines scattered volumes and direct radiation. The parameter used to estimate the intensity is estimated in calories per unit area. At the same time, it is remembered that at different times of the day the values inherent in radiation differ. In addition, energy cannot be distributed evenly over the surface of the planet. The closer to the pole, the higher the intensity, while the snow covers are highly reflective, which means that the air does not get the opportunity to warm up. Therefore, the farther from the equator, the lower the total indicators of solar wave radiation will be.
As scientists managed to reveal, the energy of solar radiation has a serious impact on the planetary climate, subjugates the vital activity of various organisms that exist on Earth. In our country, as well as in the territory of its nearest neighbors, as in other countries located in the northern hemisphere, in winter the predominant share belongs to scattered radiation, but in summer direct radiation dominates.
Of the total amount of total solar radiation, an impressive percentage belongs to the infrared spectrum, which is not perceived by the human eye. Due to such waves, the surface of the planet is heated, gradually transferring thermal energy to air masses. This helps to maintain a comfortable climate, maintain conditions for the existence of organic life. If there are no serious failures, the climate remains conditionally unchanged, which means that all creatures can live in their usual conditions.
Our luminary is not the only source of infrared spectrum waves. Similar radiation is characteristic of any heated object, including an ordinary battery in a human house. It is on the principle of perception infrared radiation Numerous devices are in operation, making it possible to see heated bodies in the dark, otherwise uncomfortable conditions for the eyes. By the way, compact devices that have become so popular recently work on a similar principle to assess through which parts of the building the greatest heat losses occur. These mechanisms are especially widespread among builders, as well as owners of private houses, as they help to identify through which areas heat is lost, organize their protection and prevent extra expense energy.
Do not underestimate the impact of infrared solar radiation on the human body just because our eyes cannot perceive such waves. In particular, radiation is actively used in medicine, since it allows to increase the concentration of leukocytes in the circulatory system, as well as to normalize blood flow by increasing the lumen of blood vessels. Devices based on the IR spectrum are used as prophylactic against skin pathologies, therapeutic in inflammatory processes in acute and chronic form. The most modern drugs help to cope with colloidal scars and trophic wounds.
Based on the study of solar radiation factors, it was possible to create truly unique devices called thermographs. They make it possible to timely detect various diseases that are not available for detection in other ways. This is how you can find cancer or a blood clot. IR to some extent protects against ultraviolet radiation, which is dangerous for organic life, which made it possible to use waves of this spectrum to restore the health of astronauts who were in space for a long time.
The nature around us is still mysterious to this day, this also applies to radiation of various wavelengths. In particular, infrared light is still not fully explored. Scientists know that its improper use can cause harm to health. Thus, it is unacceptable to use equipment that generates such light for the treatment of purulent inflamed areas, bleeding and malignant neoplasms. The infrared spectrum is contraindicated for people suffering from impaired functioning of the heart, blood vessels, including those located in the brain.
One of the elements of total solar radiation is the light visible to the human eye. Wave beams propagate in straight lines, so there is no superposition on each other. At one time, this became the topic of a considerable number scientific works: scientists set out to understand why there are so many shades around us. It turned out that the key parameters of light play a role:
As the scientists found out, objects are not capable of being sources of visible light on their own, but they can absorb radiation and reflect it. Reflection angles, wave frequency vary. Over the centuries, the ability of man to see has been gradually improved, but certain limitations are due to biological structure eyes: the retina is such that it can perceive only certain rays of reflected light waves. This radiation is a small gap between ultraviolet and infrared waves.
Numerous curious and mysterious light features not only became the subject of many works, but also were the basis for the birth of a new physical discipline. At the same time, non-scientific practices appeared, theories, the adherents of which believe that color can affect the physical state human, psyche. Based on such assumptions, people surround themselves with objects that are most pleasing to their eyes, making everyday life more comfortable.
An equally important aspect of the total solar radiation is the ultraviolet study, formed by waves of large, medium and small lengths. They differ from each other both in physical parameters and in the peculiarities of their influence on the forms of organic life. Long ultraviolet waves, for example, are mainly scattered in the atmospheric layers, and only a small percentage reaches the earth's surface. The shorter the wavelength, the deeper such radiation can penetrate human (and not only) skin.
On the one hand, ultraviolet radiation is dangerous, but without it, the existence of diverse organic life is impossible. Such radiation is responsible for the formation of calciferol in the body, and this element is necessary for the construction of bone tissue. UV spectrum is a powerful prevention of rickets, osteochondrosis, which is especially important in childhood. In addition, such radiation:
It was stated above that the total solar radiation is the amount of radiation that has reached the surface of the planet and is scattered in the atmosphere. Accordingly, the element of this volume is the ultraviolet of all lengths. It must be remembered that this factor has both positive and negative aspects of influence on organic life. Sunbathing, while often beneficial, can be a health hazard. Too long under direct sunlight, especially in conditions of increased activity of the luminary, is harmful and dangerous. Long-term effects on the body, as well as too high radiation activity, cause:
Prolonged ultraviolet irradiation provokes a violation of appetite, the functioning of the central nervous system, immune system. Also, my head starts to hurt. The described symptoms are classic manifestations sunstroke. The person himself cannot always realize what is happening - the condition worsens gradually. If it is noticeable that someone nearby has become ill, first aid should be provided. The scheme is as follows:
If the victim has lost consciousness, it is important to immediately seek help from a doctor. The ambulance team will move the person to a safe place and give an injection of glucose or vitamin C. The medicine is injected into a vein.
In order not to learn from experience how unpleasant the excessive amount of solar radiation received during tanning can be, it is important to follow the rules of safe spending time in the sun. Ultraviolet light initiates the production of melanin, a hormone that helps the skin protect itself from negative impact waves. Under the influence of this substance, the skin becomes darker, and the shade turns into bronze. To this day, disputes about how useful and harmful it is for a person do not subside.
On the one hand, sunburn is an attempt by the body to protect itself from excessive exposure to radiation. This increases the likelihood of the formation of malignant neoplasms. On the other hand, tan is considered fashionable and beautiful. In order to minimize risks for yourself, it is reasonable to analyze before starting beach procedures how dangerous the amount of solar radiation received during sunbathing is, how to minimize risks for yourself. To make the experience as pleasant as possible, sunbathers should:
The value of solar radiation for the human body is exceptionally high, both positive and negative aspects should not be overlooked. It should be realized that different people biochemical reactions occur with individual characteristics, therefore, for someone, half an hour sunbathing may be dangerous. It is reasonable to consult a doctor before the beach season, assess the type and condition of the skin. This will help prevent harm to health.
If possible, sunburn should be avoided in old age, during the period of bearing a baby. Cancer diseases, mental disorders, skin pathologies and heart failure are not combined with sunbathing.
Quite interesting to consider is the process of distribution of solar radiation. As mentioned above, only about half of all waves can reach the surface of the planet. Where do the rest disappear to? The different layers of the atmosphere and the microscopic particles from which they are formed play their role. An impressive part, as was indicated, is absorbed by the ozone layer - these are all waves whose length is less than 0.36 microns. Additionally, ozone is able to absorb some types of waves from the spectrum visible to the human eye, that is, the interval of 0.44-1.18 microns.
The ultraviolet is absorbed to some extent by the oxygen layer. This is characteristic of radiation with a wavelength of 0.13-0.24 microns. Carbon dioxide, water vapor can absorb a small percentage of the infrared spectrum. Atmospheric aerosol absorbs some part (IR spectrum) of the total amount of solar radiation.
Waves from the short category are scattered in the atmosphere due to the presence of microscopic inhomogeneous particles, aerosol, and clouds here. Inhomogeneous elements, particles whose dimensions are inferior to the wavelength, provoke molecular scattering, and for larger ones, the phenomenon described by the indicatrix, that is, aerosol, is characteristic.
The rest of the solar radiation reaches the earth's surface. It combines direct radiation, diffused.
The total value is the amount of solar radiation received by the territory, as well as absorbed in the atmosphere. If there are no clouds in the sky, the total amount of radiation depends on the latitude of the area, the height of the position celestial body, the type of land surface in this area, as well as the level of air transparency. The more aerosol particles scattered in the atmosphere, the lower the direct radiation, but the proportion of scattered radiation increases. Normally, in the absence of cloudiness in the total radiation, diffuse is one fourth.
Our country belongs to the northern ones, therefore most year in the southern regions, the radiation is significantly greater than in the northern ones. This is due to the position of the star in the sky. But the short time period May-July is a unique period, when even in the north the total radiation is quite impressive, since the sun is high in the sky, and the daylight hours are longer than in other months of the year. At the same time, on average, in the Asian half of the country, in the absence of clouds, the total radiation is more significant than in the west. The maximum strength of wave radiation is observed at noon, and the annual maximum occurs in June, when the sun is highest in the sky.
Total solar radiation is the amount of solar energy reaching our planet. At the same time, it must be remembered that various atmospheric factors lead to the fact that the annual arrival of total radiation is less than it could be. The largest difference between the actually observed and the maximum possible is typical for the Far Eastern regions in summer period. Monsoons provoke exceptionally dense clouds, so the total radiation is reduced by about half.
The largest percentage of the maximum possible exposure to solar energy is actually observed (calculated for 12 months) in the south of the country. The indicator reaches 80%.
Cloudiness does not always result in the same amount of solar scatter. The shape of the clouds plays a role, the features of the solar disk at a particular point in time. If it is open, then the cloudiness causes a decrease in direct radiation, while the scattered radiation increases sharply.
There are also days when direct radiation is approximately the same in strength as scattered radiation. The daily total value can be even greater than the radiation characteristic of a completely cloudless day.
Based on 12 months, special attention should be paid to astronomical phenomena as determining the overall numerical indicators. At the same time, cloudiness leads to the fact that the real radiation maximum can be observed not in June, but a month earlier or later.
From the edge of our planet's magnetosphere and further into outer space solar radiation becomes a factor associated with a mortal danger to humans. As early as 1964, an important popular science work on defense methods was published. Its authors were Soviet scientists Kamanin, Bubnov. It is known that for a person the radiation dose per week should be no more than 0.3 roentgens, while for a year it should be within 15 R. For short-term exposure, the limit for a person is 600 R. Space flights, especially in unpredictable conditions solar activity, may be accompanied by significant exposure of astronauts, which obliges to take additional measures to protect against waves of different lengths.
After the Apollo missions, during which methods of protection were tested, the factors influencing human health, more than one decade has passed, but to this day scientists cannot find effective, reliable methods for predicting geomagnetic storms. You can make a forecast for hours, sometimes for several days, but even for a weekly forecast, the chances of realization are no more than 5%. The solar wind is an even more unpredictable phenomenon. With a probability of one in three, astronauts, setting off on a new mission, can fall into powerful radiation fluxes. This makes even more important the issue of both research and prediction of radiation features, and the development of methods of protection against it.
The Earth receives from the Sun 1.36 * 10v24 cal of heat per year. Compared to this amount of energy, the remaining amount of radiant energy reaching the Earth's surface is negligible. Thus, the radiant energy of stars is one hundred millionth of the solar energy, cosmic radiation is two billionths, the internal heat of the Earth at its surface is equal to one five thousandth of the solar heat.
Radiation of the Sun - solar radiation- is the main source of energy for almost all processes occurring in the atmosphere, hydrosphere and in the upper layers of the lithosphere.
The unit of measurement of the intensity of solar radiation is the number of calories of heat absorbed by 1 cm2 of an absolutely black surface perpendicular to the direction of the sun's rays in 1 minute (cal/cm2*min).
The flow of radiant energy from the Sun, reaching the earth's atmosphere, is very constant. Its intensity is called the solar constant (Io) and is taken on average to be 1.88 kcal/cm2 min.
The value of the solar constant fluctuates depending on the distance of the Earth from the Sun and on solar activity. Its fluctuations during the year are 3.4-3.5%.
If the sun's rays everywhere fell vertically on the earth's surface, then in the absence of an atmosphere and at a solar constant of 1.88 cal/cm2*min, each square centimeter it would receive 1000 kcal per year. Due to the fact that the Earth is spherical, this amount is reduced by 4 times, and 1 sq. cm receives an average of 250 kcal per year.
The amount of solar radiation received by the surface depends on the angle of incidence of the rays.
The maximum amount of radiation is received by the surface perpendicular to the direction of the sun's rays, because in this case all the energy is distributed to the area with a cross section equal to the cross section of the beam of rays - a. With oblique incidence of the same beam of rays, the energy is distributed over a large area (section c) and a unit surface receives a smaller amount of it. The smaller the angle of incidence of the rays, the lower the intensity of solar radiation.
The dependence of the intensity of solar radiation on the angle of incidence of rays is expressed by the formula:
I1 = I0 * sinh,
R \u003d Q * (1-α) - I,