What is inversion? What are the main types of inversion sentences?

In general, the atmospheric temperature decreases with the increase of altitude, but under some weather conditions, the atmospheric structure above the ground will have an abnormal phenomenon that the temperature increases with the increase of altitude, which is called "inversion" in meteorology.

Classification: radiation inversion, advection inversion, topography inversion, subsidence inversion and turbulence inversion.

1, radiation inversion: often occurs in a clear and cloudless night sky. Due to the strong effective radiation on the ground, the temperature in the near-surface layer drops rapidly, while the temperature in the upper atmosphere drops less, resulting in the inversion phenomenon of upper warming and lower cooling. This inversion is the strongest before dawn and disappears from top to bottom after sunrise. The thickness of radiation inversion can reach tens to hundreds of meters. It may be thousands of meters thick in the polar regions. ?

2. Advection inversion: Warm air moves horizontally to the cold ground or air layer, and the lower warm air is affected by the cold ground or air layer and rapidly cools down, while the upper layer is less affected and cools down slowly, resulting in inversion.

It often appears in autumn, winter or spring, and may appear at any time of the day. Advection inversion may occur when the air mass from the ocean flows to the cold underlying surface in winter, or when the air flows from low latitude to high latitude in autumn. ?

3. Topographic inversion: mainly caused by topography, mainly in basins and river valleys. Because of the rapid heat dissipation on the hillside, the cold air sinks to the bottom of the valley along the hillside, and the originally warmer air at the bottom of the valley is pushed up by the cold air, resulting in the inversion of the temperature.

4. subsidence inversion: In the high-pressure control area, there is a wide range of downdraft at high altitude. Due to the adiabatic warming effect of airflow sinking, the terminal height of sinking motion appears inversion.

This inversion is more common in subtropical high. It is characterized by a large range, appearing at a certain height and being ungrounded. This inversion sometimes prevents upward turbulent diffusion like a cover, and if it lasts for a long time, it will have a very adverse impact on the diffusion of pollutants.

5. Turbulent inversion: The inversion caused by turbulent mixing in the lower layer is called turbulent inversion. When the direct reduction rate of air temperature in the gas layer is less than that of dry insulation, the temperature distribution of the gas layer gradually approaches the direct reduction rate of dry insulation after turbulent mixing.

The air temperature rising due to turbulence decreases according to the direct reduction rate of dry insulation. When the air rises to the top of the mixed layer, its temperature is lower than the surrounding air. As a result of mixing, the temperature of the upper air is reduced. When the air sinks, the situation is just the opposite, resulting in a lower temperature rise. In this way, in the turbulent weakening layer, inversion occurs.

The reason for the extended data inversion is:

1. Geographical location: the phenomenon of subsidence inversion is more likely to occur in mid-latitude areas. At latitude 30, dry air sinks, compresses, and heats itself, with more sunny days and less rain. The temperature after self-heating is higher than that of the lower air, which is more likely to lead to inversion.

2. Time factor: the distribution of inversion layer will change with time. Take the equator as an example. From summer solstice, the sun shines directly on the equator, and the mid-latitude area is more prone to inversion. ?

3. Weather factors: It is partly cloudy at night, and the ground heat dissipates quickly and the temperature drops faster, which means that the difference between the ground temperature and the upper air temperature is reduced, and the possibility of radiation inversion in the next morning is also reduced. Precipitation weather will reduce the probability of inversion, and foggy weather will increase the probability of inversion. ?

4. Terrain: When there are many valleys and hills, the cold air stays in the valleys at night and does not pass with the upper hot air flow, which partially meets the conditions for the formation of inversion, which will more easily lead to inversion. In coastal areas, the inversion layer is narrowed by the cold air blowing inland from the sea surface, and then the inversion layer is generated on the coastal ground.

5. Degree of air pollution: The heavier the air pollution, the higher the thickness of inversion layer and the more serious the inversion phenomenon.

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