The thermosphere is the "warm layer", also known as the "thermosphere" and the "ionosphere".It refers to the atmosphere between the top of the mesosphere and the altitude of 800 kilometers.The air density in this layer is very small. At 270 kilometers, the atmospheric density is only one tenth of the ground density.Air particle in solar radiation and universeHigh-energy particleUnder the action, the temperature increases rapidly, so the temperature in the atmosphere increases with the height again.[1]
Main features
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According to satellite observation data, the temperature of the thermosphere has increased dramatically since 80-160 km, increasing 970 ℃ within 80 km, 1027 ℃ at 250 km and 1201 ℃ at 500 km.However, the temperature changes little from more than 500 kilometers.The sharp increase in temperature is due to the absorption of solar ultraviolet radiation with wavelength less than 0.175 μ m by the warm layer.Because the air density is very small, under the action of solar ultraviolet rays and cosmic rays, oxygen molecules and nitrogen molecules are decomposed into atoms and in an ionized state, so there are a large number of charged particles in the thermosphere (warm layer) - charged ions and electrons, which have the ability to reflect radio waves.The stronger the degree of ionization, the stronger the ability to reflect radio waves. Without this layer, radio waves cannot be transmitted far away.[1]
Material composition
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The density of the thermosphere is very small, and its mass only accounts for 0.5% of the total atmospheric mass.In the space above 120km,atmospheredensityIt is so small that it is difficult for sound waves to propagate. At the altitude of 270km, the air density is about one tenth of the ground air density. At the altitude of 300km, the air density is only one tenth of the ground density, and the air is even thinner upward.Thermistic layer is rich inoxygenatom, air at heightionizationStatus.The strongestthe ionosphereThere are two layers, layer E and layer F.Layer E is located at about 90-130km, and layer F is located at about 160-350km.[1]
application
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Relevant studies have shown that the temporary contraction of the thermosphere is related to the sharp decline of solar ultraviolet radiation, and the major changes in solar energy output will cause drastic changes in the earth's outer atmosphere.This discovery is important for satellites in orbit and space stations.The decrease of the thickness and density of the thermogenic layer means that the satellite is easier to keep in its orbit, but at the same time, the time when garbage and other objects in space harm the satellite will also be prolonged.In addition, the ionosphere has reflectionradio wavesHuman beings can use it to transmit radio signals.[2]
