Layers of Atmosphere - Definition, Composition, Diagram, FAQs

Atmosphere

An envelope of air surrounding the earth is known as the atmosphere. The atmosphere extends up to a distance of 32,000km. It is the most important part of our environment. The atmosphere is an essential part of our biosphere as its composition is responsible for changes in weather and climate on our planet and other life-supporting systems. The atmosphere consists of different gases. Nitrogen is 78%, oxygen is 21%, argon is 0.9% carbon dioxide is 0.04%, and other traces of gases like methane, neon, and also water vapours. Our atmosphere is divided into layers.

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How many layers of the atmosphere are there?

We explain the layers of atmosphere/ describe the layers of the atmosphere

4 Layers of the atmosphere

Layers of Atmosphere

The structure of the atmosphere consists of five layers. Each layer has its characteristics.

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere
• Exosphere

We explain layers of atmosphere step by step.

earth's atmosphere diagram is shown in fig. In the diagram different layers of earth, atmosphere are shown. These layers are also called earth space layers.

Troposphere

It is the lowest layer of the atmosphere having 75% of the total weight of the atmosphere. It is 10 km thick at the poles and 18km thick at the equator. There is a 1°C temperature fall with a 165m increase in altitude. This is known as the normal lapse rate. The term “ Tropo” means change. Most of the weather phenomena take place in the troposphere as dust, storm, rainfall, snowfall, etc. In this sphere, we also see twilight, sunrise, sunset, and scattering of light. The troposphere is the hottest part of the atmosphere because it absorbs the highest amount of solar energy emitted by the rocks, mountains, and water on the earth.

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Stratosphere

It is the second layer of the atmosphere, next to the troposphere. It extends up to 3km above the surface of the earth. It is a calm and clean sphere. The absence of water vapours prevents the formation of clouds, hence providing very clear visibility. This sphere is also free of air pocket, i.e., pilots prefer to fly in this sphere, we also see the formation of mother of pearl cloud or nacreous cloud.

Stratosphere refers to the region of stratification. This sphere is divided into some permanent layers. In this sphere,m with the increase in height, a fall in temperature stops. In the lowest part of the stratosphere, almost the same temperature is found at different heights. This is the reason why it is called the stratosphere. There is the possibility of an increase in temperature in the upper part of the stratosphere. (ozone is found in which layer of the atmosphere?)

The ozone layer is found in the stratosphere. It is around 15-30km above the earth. There is plenty of ozone gas in this sphere, Hence it is known as the ozonosphere. Ozonesphere is very useful because it absorbs the ultraviolet radiations of the sun and protects life on the earth. We cannot live up to five minutes if the ozone layer is destroyed.

Mesosphere

It is the third layer next to the stratosphere. The mesosphere characteristics by low atmospheric pressure and low temperature. The temperature begins to drop from stratopause, goes on decreasing with the increase in height, and reaches a minimum of about -95℃ at a level of about 60km above the earth’s surface. At an 80-90 km altitude menopause separates the mesosphere from the thermosphere. But why temperature decreases in the mesosphere because there is some gas molecule present in the mesosphere which absorbs the radiation of the sun hence mesosphere is the coldest layer of the atmosphere.

Thermosphere

It is the fourth layer next to the mesosphere. Thermosphere characteristics are that in this sphere due to the absorption of energetic ultraviolet and X-Ray radiation from the sun temperature increase. The temperature of the thermosphere increases with height and it can rise as high as 1500 °C. It consists of a large part of the ionosphere. It extends about 80km above sea level. At an altitude range of 500–1000 km thermopause separate the exosphere from the thermosphere. The thermosphere is the hottest layer of the atmosphere.

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Exosphere

Beyond the ionosphere, there is an outermost layer in the atmosphere. It is called the exosphere (the outer layer of the atmosphere). The exosphere is the outermost layer of the earth's atmosphere. It provides space for interplanetary happenings. It ranges from 500 km to 1,000km above the earth. This part gradually merges with the outer spaces.

The layers of the atmosphere are heated through solar radiation and convection current.

This is about layers of the atmosphere.

• Ionosphere:-It extends from 60 to 500km. Due to the presence of ions - electrically charged particles it is called the ionosphere. It reflects radio waves back to the earth which helps in wireless communication. It also absorbs X-rays emitted from sunrays. Due to the ionization of the atmospheric gases by ultraviolet radiation we witness the aurora borealis and aurora australis phenomena in the North pole and south pole respectively. In this sphere, temperature increases with height because of the radiation from the sun.

Troposphere:- The temperature gradient of this layer is 6.5°C per 1,000 m (3.6°F per 1,000 ft.) of altitude. Solar radiation is absorbed by the earth (rock, soil, and water) and they radiate back to the troposphere.

Stratosphere:-Temperature increases with altitude. Temperature increases from an average -60°F (-51°C) at tropopause to a maximum of about 5°F (-15°C) at the top of the stratosphere.

Mesosphere:- The temperature of the mesosphere is about -90°C (-130°F). It is the coldest layer of the atmosphere.

Thermosphere:- The temperature of the thermosphere is low as -184℃ (-120℉) at the bottom of the layer. The temperature at the top of the layer reaches up to 3,600°F (2,000°C)

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