How many layers do scientists usually divide the earth's atmosphere into according to its height?

Scientists usually divide the earth's atmosphere into five layers according to its height: troposphere, stratosphere, mesosphere, thermosphere and escape layer.

1, the troposphere is the lowest layer of the atmosphere, from the ground to about 10- 16 km (polar about 8-9 km, equatorial about 15- 18 km). This layer concentrates about three-quarters of the mass of the whole atmosphere and almost all the water vapor. The atmospheric convection in this layer is very developed, and the temperature drops evenly with the height increase, with an average drop of 0.6℃ per rise 100 m and -55℃ near1km.

The stratosphere is from the tropopause to the height of 55 kilometers. This layer is the place where ozone is concentrated in the earth's atmosphere, especially in its lower part, that is, at the height of 15-25 km, the ozone concentration is the highest, so this layer is also called ozone layer. Although there are few water vapor and weather phenomena in the stratosphere, with the launch of meteorological rockets and satellites, it is found that the change of airflow in this layer is closely related to the weather change in the troposphere and affects each other.

3. The temperature in the middle layer decreases with the height, reaching the lowest point at about 80km, which is about -90℃. The mesosphere is from the top of the stratosphere, that is, from 55 km to 80 km.

4. The thermosphere ranges from the middle atmosphere to about 500 kilometers. The air here is extremely thin, although the temperature at the top of the thermosphere can reach 1000℃-2000℃.

The escape layer is the top of the earth's atmosphere, where the earth's gravity is very small. The temperature of this layer is extremely high, but it is almost isothermal, and the air here is also highly ionized. Most of human space activities are carried out in the escape layer (or outside the escape layer).