The amount of solar energy reaching on the surface of the Earth varies due to the movement of the Earth around its axis and the sun. These changes depend on the time of day and season. Usually, at noon, the largest amount of solar radiation falls on the ground than early in the morning or late in the evening. At noon, the Sun is in Zenith, and the length of the way of passing the rays of the sun through the atmosphere of the Earth is reduced. As a result, a smaller amount of sunlight is refracted and reflected, therefore, a larger amount of solar radiation reaches the surface of the Earth. The amount of energy falling per unit area per unit of time depends on a number of factors: latitude, local climate, season of the year, the angle of tilt surface relative to the sun. Number of solar energy, reaching the surface of the Earth, differs from average annual meaning: in winter - less than 0.8 kW * h / m 2 per day in the north of Europe and more than 4 kW * b / m 2 per day in the summer in the same region. The difference decreases as the equator approaches the equator. The amount of solar energy dependent and from the geographical location of the object: the closer to the equator, the more. For example, the average annual total solar radiation falling on the horizontal surface is: in Central Europe, Central Asia and the Central Region of Russia - approximately 1000 kW * Ch / m 2; in the Mediterranean approximately 1500 kW * Ch / m 2; In most desert regions of Africa, the Middle East and Australia - approximately 2200 kW * h / m 2. Thus, the amount of solar radiation differs significantly depending on the time of year and the geographical position. This factor plays a crucial role in calculating the efficiency of the use of power plants, which use solar batteries collectors. Fig.1.2 Distribution of solar radiation on the surface of the Earth.
1.4 The history of the development of solar collectors
People heated water using the Sun for a long time, before fossil fuel took a leading place in world energy. The principles of solar heating are known for thousands of years. The surface painted in black is very hot in the sun, while the light surfaces are heated less, the white is less than all the others. This property is used in solar collectors - the most famous devices directly using the energy of the Sun. Collectors were developed about two hundred years ago. The most famous of them - the technology of manufacturing solar collectors has reached a practically modern level in 1908, when William Bailey from the American "Carnegie Steel Company" invented a collector with a thermally insulated housing and copper tubes. This collector was very similar to a modern thermophone system (see below). By the end of World War II, Bailey sold 4,000 such collectors, and a businessman from Florida, who bought a patent, by 1941 sold almost 60,000 collectors. Insulated in the United States during World War II, the normalization of copper led to a sharp drop in the solar heaters market. To the 1973 World Oil Crisis, these devices were in oblivion. However, the crisis awakened a new interest in alternative energy sources. As a result, demand has increased and for solar energy. Many countries are vividly interested in the development of this area. The effectiveness of solar heating systems from the 1970s is constantly increasing due to the use of hardened glass collectors with a reduced iron content (it passes more solar energy than ordinary glass), improved thermal insulation and durable selective coating.
Solar energy is restored without the participation of a person naturally and is one of the environmentally friendly sources. Scientists of the whole world work on the development of systems that will expand the use of solar energy. One square meter of the Sun radiates 62,900 kW of energy. This amount of radiation is equal to the work of 1 million electrical lamps. (10)
Solar energy can be converted to beneficial energy and used for active and passive energy systems. A larger way of using sunlight is the construction of buildings, when designing which, climatic conditions were taken into account, building materials are selected, the maximum use of solar energy, for heating or cooling, lighting buildings. With this design, the construction of the building is a collector accumulating solar energy. Such buildings are environmentally friendly, comfortable and energetically independent.
The principle of active systems Using solar energy, while the solar collector is used. It absorbs the sunlight, turning it into heat, which through the coolant heats the building, heats the water and can convert it into electrical energy. Solar collectors can be used in domestic needs, agriculture and industry.
On the surface of the spherical land, solar heat and light are unevenly distributed. This is due to the fact that the angle of falling rays on different latitudes is different.
You already know that the earth's axis is inclined to the orbit plane at an angle. With its northern end, she is directed towards the polar star. The sun always illuminates half of the earth. At the same time, the northern hemisphere is more illuminated (and the day lasts longer than in a hemisphere), then, on the contrary, South. Twice a year both hemispheres are covered equally (then the duration of the day in both hemispheres is the same).
When the Earth turns to the Sun by the North Pole, then it illuminates more and heats the northern hemisphere. Days are getting longer than a night. There is a warm season - summer. On the pole and in the sun, the sun shines around the clock and does not go beyond the horizon (the night does not occur). This phenomenon is called polar day. On the pole, it lasts 180 days (half a year), but the further south, the duration decreases to the day on the parallel 66.5 0 Mon. sh. This parallel is called the northern polar circle. The south of this line the Sun is lowered by the horizon and the change of day and night takes place in the usual order for us - daily. June 22 - the sun's rays will fall over (under the highest angle - 90 0) on the parallel 23.5 pn. sh. This day will be the longest, and the night is short in the year. This parallel is called the Northern Tropic, and the day is June 22 - the summer solstice.
Currently, the south pole is distracted from the Sun and it illuminates less and heats the southern hemisphere. There is winter. On the pole and the sugar part of the day the solar rays do not fall at all. The sun does not appear due to the horizon and the day does not occur. This phenomenon is called polar night. On the pool itself, it lasts 180 days, and the farther north, it becomes shorter to one day on parallels 66.5 0 Yu. sh. This parallel is called the southern polar circle. The north of her sun appears on the horizon and the change of day and night occurs every day. June 22 will be the shortest year. For the southern hemisphere he will be the winter solstice.
After three months, September 23, the Earth will take this situation regarding the Sun, when the sun's rays equally illuminate both the northern and southern hemisphere. Stepped with sun rays fall at the equator. On the whole earth, except for poles, the day is equal to the night (12 hours). This day is called autumn equinox day.
After three months, on December 22, the Southern Hemisphere will return to the Sun. Summer will come there. This day will be the longest, and the night is the shortest. A polar day will come in the indoor region. The rays of the sun fall on the parallel 23.5 0 y. sh. But in the northern hemisphere will be winter. This day will be the shortest, and the night is long. Parallel 23.5 0 yu. sh. Call the southern tropical, and the day is December 22 - the winter solstice.
After three months, March 21, again both hemispheres will be covered equally, the day will be equal to the night. The rays of the sun falling in the equator. This day is called spring equinox.
In Ukraine, the greatest height of the sun at noon - 61-69 0 (June 22), the smallest - 14-22 0 (December 22).
The sun is the main source of heat and light on Earth. This huge gas ball with a temperature on the surface of about 6000 ° C emits a large amount of energy called solar radiation. It heats our land, moves air, forms a circulation of water, creates conditions for the lives of plants and animals.
Passing through the atmosphere, some of the solar radiation is absorbed, the part is dissipated and reflected. Therefore, the flow of solar radiation, coming to the surface of the Earth, gradually weakens.
Solar radiation enters the surface of the ground straight and scattered. Direct radiation represents the flow of parallel rays running directly from the Sun disk. Scattered radiation comes from all over the sky. It is believed that the flow of heat from the Sun on 1 hectare of land is equivalent to burning almost 143 thousand tons of coal.
The sun rays passing through the atmosphere, it is very hot. The heating of the atmosphere comes from the surface of the Earth, which, absorbing solar energy, turns it into thermal. Air particles, in contact with the heated surface, get warm and carry it into the atmosphere. So the lower layers of the atmosphere are heated. Obviously, the more gets the surface of the earth of solar radiation, the stronger it heats up, the stronger the air heats up from it.
The air temperature is measured by thermometers (mercury and alcohol). Alcohol thermometers are used when the air temperature is lower than - 38 ° C. On meteorological stations, the thermometers are placed in a special booth, built of separate plates located at a certain angle (blinds), between which air freely circulates. The direct solar rays do not fall on the thermometers, thus, the air temperature is measured in the shade. The booth itself is at an altitude of 2 m from the earth's surface.
Numerous air temperature observations have shown that the highest temperature was observed in Tripoli (Africa) (+ 58 ° C), the lowest at the East station in Antarctica (-87.4 ° C).
The flow of solar heat and the temperature distribution depends on the latitude of the place. The tropical area gets more heat from the Sun than moderate and polar latitudes. Most of all heat receive equatorial areas of the sun - the star of the solar system, which is for the planet the Earth source of a huge amount of heat and dazzling light. Despite the fact that the sun is from us at a considerable distance and only a small part of its radiation comes to us, this is enough to develop life on Earth. Our planet rotates around the sun in orbit. If you observe the Earth from the spacecraft during the year, then it can be noted that the sun always illuminates only one half of the earth, therefore, there will be a day, and at the opposite half at that time there will be a night. The earth's surface gets warm only during the day.
Our land is heated unevenly. The uneven heating of the Earth is explained by its spherical form, so the angle of falling the solar beam in different areas is varied, and therefore various parts of the earth receive a different amount of heat. At the equator, the sun rays fall again, and they heat the ground strongly. The farther from the equator, the angle of falling the beam becomes less, and therefore, and fewer heat get these territories. The one and the same power bundle of solar radiation heats the equator much less area, as it drops sharply. In addition, rays falling at a smaller angle than at the equator - permeating the atmosphere, pass in it a larger way, as a result of which part of the sun's sun is dissipated in the troposphere and does not reach the earth's surface. All this indicates that when removing from the equator, the air temperature decreases to the north or south, since the angle of falling the solar beam is reduced.
The distribution of precipitation on the globe depends on how many clouds containing moisture is formed above this territory or how much the wind can bring them. The air temperature is very important, because the intensive evaporation of the moisture occurs at high temperatures. The moisture evaporates, clouds up and clouds are formed at a certain altitude.
The air temperature decreases from the equator to the poles, therefore, the amount of precipitation is maximally in equatorial latitudes and decreases to the poles. However, on land, the distribution of precipitation depends on a number of additional factors.
A lot of precipitation falls over coastal territories, and as they remove from the oceans, their number decreases. More precipitation on the winding slopes of the mountain ranges and significantly less on the leeward. For example, at the Atlantic Coast of Norway in Bergen drops 1730 mm of precipitation per year, and in Oslo (for the ridge - approx. From site), there is an average of more than 11,000 mm of precipitation per year. Such an abundance of moisture brings in these places the wet summer south-western monsoon, which rises the steep slopes of the mountains, is cooled and shed by powerful rain.
Oceans, the water temperature of which varies much slower than the temperature of the earth's surface or air, have a strong softening effect on the climate. At night and winter, the air over the oceans cools much slower than above the land, and if the ocean air masses move over the continents, it leads to warming. Conversely, during the day and summer, the sea breeze cools the land.
The distribution of moisture on the earth's surface is determined by the cycle of water in nature. Every second into the atmosphere, mostly from the surface of the oceans, a huge amount of water evaporates. Wet ocean air, rushing over the continents, cooled. The moisture is then condensed and returns to the earth's surface in the form of rain or snow. Partially it is preserved in the snow cover, rivers and lakes, and partially returns to the ocean, where evaporation is happening again. This completes the hydrological cycle.
The distribution of precipitation affects the flow of the world's ocean. Above the districts near which warm currents are undergoing, the amount of precipitation increases, since the air heats up from warm water masses, it rises up and clouds with sufficient water. Over the territories, next to which cold flows are undergoing, the air is cooled, it drops down, the clouds are not formed, and the precipitation falls significantly less.
Since water plays an essential role in erosion processes, it thus affects the movement of the earth's crust. And any redistribution of mass due to such movements in the conditions of the land rotating around its axis is capable, in turn, contribute to the change in the position of the earth's axis. During the glacial epochs, the sea level is lowered, as water is accumulated in glaciers. This, in turn, leads to the growing continents and an increase in climatic contrasts. Reducing the river flow and decrease in the world's ocean levels to achieve the warm ocean flows of cold regions, which leads to further climatic changes.
How the height of the sun is changing over the horizontal volume throughout the year. To find out this, remember the results of your observations for the shadow length, which throws away the gnomon (six of 1 m long) at noon. In September, the shadow was the same length, in October it became longer, in November - even longer, in the 20th of December - the longest. From the end of December, the shadow decreases again. The change in the length of the shadow of the mini-mona shows that throughout the year the sun at noon is at different height above the horizon (Fig. 88). The higher the sun over the horizon, the shorter the shadow. The lower the sun over the horizon, the longer the shadow. The top of all rises the sun in the northern hemisphere on June 22 (on the day of summer solstice), and its lowest position is December 22 (on the day of the winter solstice).
Why the heating of the surface depends on the height of the sun. From fig. 89 It can be seen that the same amount of light and heat coming from the Sun, with its high position falls on a smaller area, and with low - more. Ka-bed plot will heat up more? Of course, less, because rays are concentrated there.
Consequently, the higher the sun over the horizon, the rectilinery falls its rays, the more the earth's surface is heated, and from it and air. Then summer comes (Fig. 90). The lower the sun over the horizon, the less the angle of drops of rays, and the less the surface heats up. Winter comes.
The greater the angle of falling the sun's rays to the earth's surface, the more it is illuminated and on-sink.
How the surface of the earth is heated. On the top of the spherical land, the sun rays fall at different angles. The highest angle of the beams at the equator. In the direction of the poles, it decreases (Fig. 91).
Under the highest angle, almost stepped, the sun rays fall at the equator. The earth's surface receives the most solar heat there, therefore the Equator is hot all year round and the change of seasons does not happen.
The farther from the equator to the north or south, the angle of falling the sun's rays is less. As a result, the surface and air are heated less. It becomes cooler than at the equator. Seasons appear: Winter, Spring, Summer, Autumn.
On the poles and the sugar areas in winter, the sun rays do not fall at all. The sun on several mesenses does not appear because of the horizontal, and the day does not occur. This phenomenon is called polar night . The surface and the air are very cooled, so winter is very severe there. The Le - the same sun does not go beyond the horizon and shines the round day (the night does not occur) - it polar day . It would seem if summer continues for so long, then the surface should be nervous. But the sun is low above the horizon, its rays only slide on the surface of the Earth and almost do not heat it. Therefore, summer near the field owls is cold.
Lighting and heating surfaces depend on its location on Earth: the closer to the equator, the greater the angle of falling the sun's rays, the stronger the surface is heated. As it removed from the Ek Vator to the poles, the incidence of rays decreases, respectively, the surface is heated less, and it becomes colder. Material from site.
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| In the spring of the plant begins to grow rapidly |
The meaning of light and heat for wildlife. Sunlight and warmly needed to everything alive. In the spring and summer, when there are many lights and heat, the growing are in bloom. With the advent of autumn, when the sun over the horizon decreases and decreases the flow of light and heat, the plants are discharged by the foliage. With the onset of winter, when the duration of the day is small, nature is at rest, some animals (bears, badgers) even fall into the hibernation. When the spring and the sun rises more and above, the plants begin with an active growth again, the animal world comes to life. And all this thanks to the sun.
Decorative plants, such as monster, ficus, asparagus, if they gradually turn to light, grow uniformly in all directions. But blooming plants poorly tolerate such a permutation. Azalea, Camellia, Geranium, Fuchsia, Begonia almost immediately dump buds and even leaves. Therefore, during the flowering "Self-reliable" plants, it is better not to rearrange.
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On this page, material on the themes:
- briefly distribution of light and heat on the globe
I, like everyone, love summer for its warm rays of the sun, which warmed after the cold winter. But in other countries, hot weather can be all year round or, on the contrary, in some places only a couple of months can be called summer. Why is solar heat so unevenly distributed? Now I'll figure it out.
Solar warm on earth
Everyone knows and it is clear that our sun is the only and unique star in the solar system, and all the cosmic bodies make a rotational movement around it. Radiation from the Sun allows you to maintain life on our planet. At the same time, plants, people and animals are very dependent on the light of the sun. For example, in the tundra due to the small amount of sunlight, a very low temperature is installed, vegetation - small sizes and a short period when plants grow. Solar energy is obtained by lower air layers of the Earth (Troprosphere), in which the clouds are formed. For living organisms, by the way, the sun is useful by its ultraviolet rays, which are given very important vitamin D.
The main reason for uneven solar heat distribution
If we take a look at the globe, we immediately note that the axis of the earth has a certain slope. That is, while the earth is spinning around our main star, its angle of inclination is unchanged. In this regard, the Earth goes through the larger side to the Sun Northern Hemispheres, then South. Accordingly, the angle under which the rays of the sun fall on the surface of the planet. Therefore, it is more heated and the southern, then the northern hemisphere is illuminated.
Additional influencing factors
The angle of falling rays is not the only factor on which the temperature of our planet depends. There are still a number of signs:
- terrain;
- precipitation;
- the presence of glaciers;
- the state of the atmosphere.
Each of them depends on the territory. For example, in the UK, the temperature will be lower due to the continuous presence of clouds. After all, because of this, the sun's rays can not reach the earth's surface to the fullest. All these additional factors are some obstacles to the passage of the rays of the Sun.
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