Stratosphere Temperature Profile Maintained by Photoionization
The question asks which atmospheric layer's temperature profile is maintained by the photoionization of gas molecules. Photoionization involves the removal of an electron from an atom or molecule by absorbing photons.
Understanding Atmospheric Heating Mechanisms
Different atmospheric layers have distinct temperature profiles due to various energy absorption processes:
- Troposphere: Heated from below by the Earth's surface; temperature decreases with altitude.
- Stratosphere: Heated from above by the absorption of ultraviolet (UV) radiation, primarily by ozone. This heating causes the temperature to increase with altitude.
- Mesosphere: Temperature decreases with altitude.
- Thermosphere: Heated by direct absorption of high-energy solar radiation (X-rays and extreme UV), causing significant ionization and very high temperatures, although the air is extremely thin.
Role of Photoionization in the Stratosphere
The primary process maintaining the Stratosphere temperature profile involves ozone ( $O_3$ ) absorbing harmful UV radiation from the sun. While direct photoionization (creating ions and free electrons) is most significant in the thermosphere, the absorption of UV photons by ozone molecules leads to their dissociation and subsequent recombination, releasing heat. This absorption process is fundamental to the stratosphere's temperature structure, where temperature increases with height. The term 'photoionization' in the question likely broadly refers to photo-chemical processes driven by solar radiation that affect the temperature profile, with ozone's UV absorption being the key mechanism in the stratosphere.
Conclusion
The absorption of solar UV radiation by ozone molecules, a process related to photo-chemistry and energy transfer, is responsible for the temperature profile of the Stratosphere.
Answer Summary
The correct option is the one corresponding to the Stratosphere.
Important Questions from Atmosphere
In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index?
1. Carbon dioxide
2. Carbon monoxide
3. Nitrogen dioxide
4. Sulfur dioxide
5. Methane
Select the correct answer using the code given below.
A layer in the Earth's atmosphere called Ionosphere facilitates radio communication. Why?
1) The presence of ozone causes the reflection of radio waves to Earth.
2) Radio waves have a very long wavelength.
Which of the statements given above is/are correct?
The jet aircrafts fly very easily and smoothly in the lower stratosphere. What could be the appropriate explanation?
1) There are no clouds or water vapour in the lower stratosphere.
2) There are no vertical winds in the lower stratosphere.
Which of the statements given above is/are correct in this context?
The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere, because it absorbs
Which one of the following is associated with the issue of control and phasing out of the use of ozone-depleting substances?
