We are going to discuss the mesosphere. It is an essential layer of the atmosphere that keeps the Earth safe from UV rays and other harmful radiation from the universe. Let’s learn about the characteristics of the mesosphere, temperature, and important facts.
What is the Mesosphere?
The mesosphere is the third layer of the atmosphere. This layer is above the stratosphere and below the thermosphere. The word ‘mesosphere’ is derived from the Greek words ‘Mesos sphaira,’ which translates to ‘middle sphere.’ Meso means middle because it is the middle layer of the atmosphere. So its name is the mesosphere.
What is the mesosphere made of? The mesosphere contains a layer of liquid iron and nickel. It also covers noctilucent clouds,” or polar mesospheric clouds. It is a solid layer covering 78% nitrogen and 21% oxygen. All other chemical species form the remaining 1%.
Height: It extends from about 50 to 85 km or 31-53 miles above the planet.
Characteristics of the mesosphere: Mesosphere is a cold and middle layer.
- The mesosphere extends from the top of the stratosphere to about 80 kilometers or 50 miles above the earth’s surface.
- It is vacuumed as it contains a limited amount of helium and hydrogen.
- Meteors burn in this layer due to friction with air molecules.
The mesosphere temperature: Fewer air molecules absorb incoming electromagnetic radiation from the sun. The carbon dioxide in the atmosphere also helps to make this layer.
- The temperature range is minus 5 degrees Celsius (-5°C) to minus 93 degrees Celsius (-93°C).
- Temperature decreases with altitude.
- It means the air gets colder as we go higher in the mesosphere, near about minus 93 degrees Celsius. Mesopause is the boundary between the mesosphere and the thermosphere. That’s why the mesosphere is the coldest layer of the Earth’s atmosphere.
Color: Various colors occur here because each layer’s particles and dominant gases act as prisms, filtering out specific light colors. The mesosphere layer commonly looks green and blue.
Temperature: At the base of the mesosphere, near the mesopause (the boundary with the thermosphere), the temperature can range from about -90 degrees Celsius (-130 degrees Fahrenheit) to -40 degrees Celsius (-40 degrees Fahrenheit). However, the exact temperature can vary depending on factors such as latitude, season, and time of day.
As you move higher up within the mesosphere, temperatures continue to drop. At the top of the mesosphere, near the stratopause (the boundary with the stratosphere), temperatures can reach as low as -120 degrees Celsius (-184 degrees Fahrenheit) or even colder.
Important facts about the mesosphere: Mesosphere has a lot of fascinating facts. Here are some common facts about it.
- It is less dense than a stratosphere due to the thin layer of gases.
- Aircraft cannot fly high enough to reach the mesosphere. Most aircraft fly in the troposphere and in the stratosphere, but they cannot fly in the mesosphere because they cannot reach that much height of the mesosphere.
- The mesosphere protects the earth’s surface from being hit by most meteoroids.
- It experiences atmospheric gravity waves and atmospheric tides.
- It protects the ozone layer from greenhouse gases and keeps other layers safe.
- An unknown type of lightning occurs in the mesosphere layer. It is referred to as ‘sprites’ or ‘elves.’
- This clear is very important for the earth’s protection. The mesosphere burns most matures and asteroids before reaching the earth’s surface.
What happens in the Mesosphere?
The mesosphere is an important atmospheric layer where several interesting phenomena occur. Here are some key features and processes that take place in the mesosphere:
Temperature decrease: As mentioned earlier, the temperature decreases with increasing altitude in the mesosphere. The mesopause, the boundary between the mesosphere and the thermosphere, represents the coldest part of the Earth’s atmosphere.
Airglow: In the mesosphere, various chemical reactions emit faint light, known as airglow. These reactions involve the interaction of molecules and atoms with solar radiation, producing glowing emissions that can be observed from the Earth’s surface during nighttime.
Mesospheric winds: The mesosphere experiences strong winds known as mesospheric winds. These winds are mainly caused by gravity waves, disturbances in the atmosphere generated by weather patterns, or topographical features. Mesospheric winds can have significant impacts on atmospheric circulation and dynamics.
Meteoric ablation: The mesosphere is where most meteoroids (small celestial objects) enter the Earth’s atmosphere. When meteoroids encounter mesospheric gases, they undergo rapid heating and disintegration due to friction, known as ablation. This process creates visible meteors or “shooting stars” as they streak across the night sky.
Noctilucent clouds: Noctilucent clouds, also known as polar mesospheric clouds, form in the mesosphere at high latitudes during the summer. These thin, glowing clouds consist of ice crystals and can be observed in the twilight sky after sunset or before sunrise. They provide valuable information about the state and composition of the mesosphere.
What does the Mesosphere do?
The mesosphere plays several important roles in the Earth’s atmosphere and overall climate system. Here are some key functions of the mesosphere:
Absorption of Solar Energy: The mesosphere absorbs some of the Sun’s incoming ultraviolet (UV) radiation. This absorption helps protect the lower layers of the atmosphere, including the ozone layer in the stratosphere, from excessive UV radiation. The absorption of solar energy in the mesosphere also contributes to heating the upper atmosphere.
Airglow and Atmospheric Chemistry: The mesosphere is responsible for the production of airglow, a faint emission of light caused by chemical reactions in the upper atmosphere. These reactions involve interactions between atoms, molecules, and ions, contributing to the atmosphere’s overall chemistry. Studying airglow provides valuable insights into the composition and dynamics of the mesosphere.
Gravity Wave Generation: The mesosphere is a region where gravity waves are generated. Gravity waves are disturbances in the atmosphere that result from various sources, such as weather systems, mountains, or convective processes. These waves are crucial in transporting energy and momentum throughout the atmosphere and influencing atmospheric circulation.
Meteoric Input: The mesosphere is where most meteors burn up upon entering the Earth’s atmosphere. As meteoroids collide with the mesospheric gases, they undergo rapid heating and ablation, creating visible meteors or “shooting stars.” This input of meteoric material into the mesosphere has implications for the overall composition of the upper atmosphere.
Noctilucent Cloud Formation: Noctilucent clouds, which form in the mesosphere, provide insights into the state of the upper atmosphere. These clouds consist of ice crystals and are primarily observed near polar regions during summer. Monitoring and studying noctilucent clouds help researchers understand changes in the mesosphere, including its temperature, moisture content, and dynamics.
The mesosphere is the protective layer of the earth. Modern technology and poisonous gas are affecting this layer day by day. Global warming and ice melting are proof of it. So we should be careful about it.
References:
Venkat Ratnam, M.; Patra, A. K.; Krishna Murthy, “Tropical mesopause: Is it always close to 100 km?”. Journal of Geophysical Research.
“The Mesosphere – overview | UCAR Center for Science Education.”
IUPAC, Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Online corrected version: “mesosphere.”
Mesosphere (Wayback Machine Archive), Atmosphere, Climate & Environment Information ProgGFKDamme (UK Department for Environment, Food, and Rural Affairs).
