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en:lesson04 [2019/10/08 10:42]
golikov created
en:lesson04 [2019/10/22 13:38]
golikov
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-====== Satellite ​imagery ​analysis ======+====== Satellite ​image analysis ======
  
 ===== Weather satellite orbits ===== ===== Weather satellite orbits =====
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 As a result of interactions with the atmosphere, the intensity of solar radiation at the surface of the Earth in comparison with its value in the upper layers of the atmosphere decreases by more than half. As a result of interactions with the atmosphere, the intensity of solar radiation at the surface of the Earth in comparison with its value in the upper layers of the atmosphere decreases by more than half.
  
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 Solar radiation coming to the surface of the Earth is not completely absorbed by it. Part of the radiation is reflected by the surface, and only the upper layer of the earth'​s surface is involved in the reflection, in which radiation is absorbed and converted. Such a layer includes the entire grass and vegetative mass of the forest, the first tens of meters of clear water and decimeters of muddy water, as well as decimeters of snow, a few centimeters of sand and a fraction of millimeters of dark soil. The reflectivity of the Earth'​s surface depends on the kind of bodies, their physical properties, color and condition. The ratio of reflected radiation to the total radiation of the Sun and the atmosphere is called albedo. Albedo values ​​are most often expressed as a percentage. The albedo of the earth'​s surface varies widely. This is due to the type of landscape zones, and in temperate and high latitudes also with the change of seasons. So, in the central parts of the polar regions the reflectivity is great and varies little in the annual course: in Antarctica - about 85%, in the central Arctic - about 80%. In July, a decrease in the albedo in the Arctic (up to 65%) is associated with more intense melting of snow than in December in Antarctica. Solar radiation coming to the surface of the Earth is not completely absorbed by it. Part of the radiation is reflected by the surface, and only the upper layer of the earth'​s surface is involved in the reflection, in which radiation is absorbed and converted. Such a layer includes the entire grass and vegetative mass of the forest, the first tens of meters of clear water and decimeters of muddy water, as well as decimeters of snow, a few centimeters of sand and a fraction of millimeters of dark soil. The reflectivity of the Earth'​s surface depends on the kind of bodies, their physical properties, color and condition. The ratio of reflected radiation to the total radiation of the Sun and the atmosphere is called albedo. Albedo values ​​are most often expressed as a percentage. The albedo of the earth'​s surface varies widely. This is due to the type of landscape zones, and in temperate and high latitudes also with the change of seasons. So, in the central parts of the polar regions the reflectivity is great and varies little in the annual course: in Antarctica - about 85%, in the central Arctic - about 80%. In July, a decrease in the albedo in the Arctic (up to 65%) is associated with more intense melting of snow than in December in Antarctica.
 Average albedo values ​​for various types of land surface (in%): Average albedo values ​​for various types of land surface (in%):
  
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 The albedo of the water surface is on average smaller than most natural land surfaces and depends on the angle of incidence of the rays, on the height of the Sun, the ratio of direct and scattered radiation, and the waves of the sea surface. With the position of the Sun at the zenith of the calm sea albedo for direct radiation is 2%. With a decrease in the height of the Sun, the albedo increases. With great ocean turmoil, when foam and lamb are formed, the sea albedo increases. The albedo of the water surface is on average smaller than most natural land surfaces and depends on the angle of incidence of the rays, on the height of the Sun, the ratio of direct and scattered radiation, and the waves of the sea surface. With the position of the Sun at the zenith of the calm sea albedo for direct radiation is 2%. With a decrease in the height of the Sun, the albedo increases. With great ocean turmoil, when foam and lamb are formed, the sea albedo increases.
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 The cloud temperature can determine the height of the clouds, because the higher the clouds, the colder they are. The cloud temperature can determine the height of the clouds, because the higher the clouds, the colder they are.
  
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 The range of infrared radiation with a wavelength of 10 microns. The range of infrared radiation with a wavelength of 10 microns.
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 In order to see the fog at night, the method of subtracting infrared signals is used. From a signal with a wavelength of 4 μm, a signal with a wavelength of 10 μm is subtracted. In order to see the fog at night, the method of subtracting infrared signals is used. From a signal with a wavelength of 4 μm, a signal with a wavelength of 10 μm is subtracted.
  
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en/lesson04.txt · Last modified: 2021/04/05 11:28 by golikov