Atmosphere

Atmosphere

The atmosphere is a layer of various gases surrounding the Earth. It is divided into four major layers. These layers are troposphere, stratosphere, mesosphere and thermosphere as shown in Figure 1. Each layer is characterized by specific temperature and air pressure.

Atmospheric Layers

The atmosphere is divided into different layers, each with distinct characteristics. These layers include the Troposphere, Stratosphere, Mesosphere, and Thermosphere.

Layers of the atmosphere

Troposphere

1. The Troposphere is the lowest layer of the atmosphere. It extends from the Earth's surface up to approximately 10 kilometers.
2. This is where human beings and other living organisms live, and where all human activities take place.
3. Passenger and cargo flights typically operate within this layer.
4. In the Troposphere, temperature decreases as altitude increases.

Stratosphere

1. The Stratosphere lies between the Troposphere and Mesosphere, extending from approximately 10 kilometers to 50 kilometers above the Earth's surface.
2. Occasionally, passenger and cargo planes fly in the lower part of the Stratosphere, especially when there are heavy clouds in the Troposphere.
3. This layer is vital for life because it contains the ozone layer, which protects the Earth from the Sun's harmful rays.
4. In the Stratosphere, temperature increases with altitude due to the absorption of ultraviolet rays by the ozone layer.

Mesosphere

1. The Mesosphere is located above the Stratosphere, extending from about 50 kilometers to 85 kilometers above the Earth's surface.
2. This is a very cold layer where temperatures decrease with altitude, reaching about -90°C at the mesopause (the boundary between the Mesosphere and Thermosphere).

Thermosphere

1. The Thermosphere is the highest layer of the atmosphere, found above the Mesopause. It stretches from approximately 85 kilometers to 1,000 kilometers above the Earth's surface.
2. In the Thermosphere, temperatures can soar to around 2,000°C, primarily due to the absorption of ultraviolet and X-ray radiation from the Sun, which heats atoms and molecules.
3. This layer plays an important role in communication as it reflects radio waves.
4. The temperature in the Thermosphere fluctuates significantly between day and night and across different seasons.