The average temperature of the atmosphere is 15 ° C. This temperature is defined as the statistical average obtained from its maximum and minimum temperatures.
If there were no atmosphere, the average temperature on Earth would be -32 ° C. The maximum and minimum temperatures of the atmosphere vary according to the hemisphere, being the maximums for the northern hemisphere between July and August, and for the southern hemisphere between January and February.
The atmosphere allows the presence of solar radiation that warms the surface of the Earth, and also prevents the exit of infrared radiation that the Earth's surface returns, thus maintaining heat.
This is the so-called greenhouse effect, which is generated by CO 2 and water vapor in the troposphere. The ozone layer absorbs radiation from the Sun and helps increase the temperature in the upper part of the stratosphere.
At the top of the thermosphere are gases that absorb radiation from the Sun and heat the atmosphere.
In order to study and analyze how the atmosphere behaves, it is very useful to divide it into several layers, which maintain the thermal gradient more or less constant.
Troposphere
The troposphere extends from the earth's surface to a height of between 6 and 20 kilometers. It is thickest at the equator, at about 18 to 20 kilometers.
At the poles, the atmospheric thickness decreases, reaching about 6 kilometers. Average temperatures also drop from 15 ° C at the surface to -51 ° C at the top of the troposphere.
Stratosphere
The stratosphere is located above the troposphere and extends 50 kilometers above the earth's surface. It contains between 85 and 90% of the atmospheric ozone.
Ozone absorbs ultraviolet light from solar radiation and causes a temperature inversion; that is, temperatures increase rather than decrease with height.
Temperatures range from about -51 ° C at the bottom to -15 ° C at the top.
Mesosphere
The mesosphere is located above the stratosphere and has an extension of 85 kilometers above the earth's surface.
The temperature decreases from -15 ° C at the edge of the stratosphere to -120 ° C at the bottom of the thermosphere.
Meteorites vaporize in the mesosphere, giving it a higher concentration of metal ions than other atmospheric layers.
Thermosphere
From the top of the mesosphere, the thermosphere extends between 500 and 1000 kilometers above the Earth's surface.
The gases are thinner in this layer, absorb ultraviolet radiation and X-rays from the Sun, and cause temperatures to rise to 2000 ° C near its top.
Exosphere
The outermost atmospheric layer extends 10,000 kilometers above Earth and is primarily hydrogen and helium.
Temperatures rise from 2000 ° C at the bottom of the exosphere but, as the air is very thin, they transmit little heat.
References
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