It rises very rapidly.
Explanation
The atmosphere is divided into concentric layers based on temperature profiles: the Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere. The Thermosphere is located immediately above the Mesopause, extending from approximately 80 km to 400 km altitude.
Analysis of Temperature Trend
In the Thermosphere, the temperature behavior is distinct from the underlying Mesosphere:
- Rapid Temperature Rise: Unlike the Mesosphere where temperature decreases with height, in the Thermosphere, the temperature rises very rapidly with increasing altitude.
- Cause of Heating: This increase is primarily caused by the absorption of extremely short-wave, high-energy solar radiation (such as X-rays and ultraviolet radiation) by gas molecules and atoms.
- Magnitude: Temperatures in this layer can reach extremely high values, often exceeding 1,500°C to 2,000°C. However, due to the extremely low density of air molecules, the heat content is low, and the temperature would not be felt in the conventional sense by a human body.
- Ionosphere Connection: The lower part of the Thermosphere contains the Ionosphere, where ionization of gases occurs, further contributing to the thermal dynamics of this layer.
Therefore, the characteristic feature of the Thermosphere is a sharp increase in temperature with height.
Key Takeaway: In the Thermosphere, temperature increases with altitude due to the direct absorption of high-energy solar radiation by atmospheric gases.