Layers of Atmosphere of Earth
What do you mean by the atmosphere? An atmosphere is a thick blanket of gaseous particles that are present in the surrounding of the Earth. These gaseous particles are held near to the Earth’s surface due to the gravitational force of attraction by Earth. There are many constituents within the atmosphere but it is dominated by Nitrogen, Oxygen, and Argon gas. The life cycle of various organisms on planet Earth exists due to the existence of the atmosphere. In this article, the layers of the atmosphere and composition of the atmosphere are explained in a detailed manner.
Layers of Atmosphere Structure
What are the different layers of the atmosphere? There are mainly five layers in the atmosphere of Earth based on the exerted pressure and height above sea level. The atmospheric pressure decreases with altitude as we move upwards. The atmospheric pressure is maximum at sea level and minimum at greater heights. The higher temperature comes up with lower pressure and lower atmospheric pressure is dealt with by the cloudy skies and moist weather. On the other side, higher pressure is dealt with by the clear and sunny skies. Always warm air moves upwards and creates a low-pressure zone while cold heavy air moves downwards and creates a high-pressure zone.
| Different Layers of Atmosphere | Height | Temperature with Height | Upper Limit |
| Troposphere | 0- 18 Km | Decreases | Tropopause |
| Stratosphere | 18- 50 Km | Increases | Stratopause |
| Mesosphere | 50- 90 Km | Decreases | Mesopause |
| Thermosphere/ Ionosphere | 80- 640 Km | Increases | Thermopause |
| Exosphere | Up to 10,000 Km | Increases | Exopause |
Composition of Atmosphere
You will be surprised to know that our atmosphere is composed of different gaseous particles. These gases are helpful for maintaining life on the Earth. The atmosphere also consists of aerosols which are solid and liquid particles present in the atmosphere. These constituents of the atmosphere help to maintain optimal temperature and pressure which suits the life forms. It blocks the harmful rays of sunlight like ultraviolet (UV) rays. Nitrogen Gas is the most abundant element in the earth’s atmosphere. The Constituents of the Atmosphere are given below.
| Constituents of Atmosphere | Percentage |
| Nitrogen Gas | 78.09% |
| Oxygen Gas | 20.95% |
| Argon Gas | 0.93% |
| Other Miscellaneous Gas | 0.03% |
5 Layers of Atmosphere
Here, we are discussing the all 5 layers of the atmosphere of Earth in detail.
1. Troposphere
The troposphere is the lowest layer of Earth’s atmosphere. It extends from ground level to 8 Km at the poles and 18 Km at the equator. Entire weather is confined inside this layer of atmosphere. Whatever happens in the weather like storms, rainfall, etc. occurs in this layer. Several dust particles, water vapours, and other impure gaseous particles are mainly found here. What we breathe during the respiration process exists here.
Since it absorbs the highest heat of Earth radiated by its surface, this layer of atmosphere maintains the Earth warm. In this layer, the temperature goes down with the height at the rate of 6.5° degrees per 1000 meters which is generally called a normal lapse rate. The upper limit of the troposphere is known as tropopause which is about 1.5 Km thick. The tropopause is the layer that separates the troposphere from the above stratosphere.
2. Stratosphere
The Stratosphere lies above the troposphere. It extends from ground level to about 50 Km height. In the lower stratosphere, there is feeble or weaker wind circulation and cirrus clouds are present. It facilitates conducive flying atmospheric conditions. Hence, airplanes, aircrafts, and jets fly through the lower stratosphere.
It also consists of an ozone layer which acts as a safeguard as it absorbs ultraviolet rays of sunlight. In this way, it helps to reduce the temperature of Earth. The ozone layer extends from ground level to 15-30 Km height. The temperature increases with height in this layer due to the presence of ozone molecules. Nowadays this ozone layer has been depleted due to excessive emission of greenhouse gases on the Earth’s surface. The ozone layer depletion is very dangerous for Earth as it may increase the temperature of Earth and cause global warming. The upper layer of the stratosphere is known as stratopause.
3. Mesosphere
The Mesosphere is the third layer of Earth’s atmosphere which lies above the stratosphere. It extends from ground level to 50-90 Km height. In this layer, the temperature goes down with the height and makes it the coldest layer of the atmosphere. The temperature can reach the lowest of -90°C at a height of 80-90 Km. In this layer, the celestial bodies like meteorites burn up while entering into this layer of the atmosphere from outer space. The upper layer of the mesosphere is known as mesopause.
4. Thermosphere/ Ionosphere
The Thermosphere lies above the mesosphere. It extends from ground level to 80-640 Km height. In this layer, the temperature increases with the height due to the presence of ultraviolet and X-ray radiation from the sun. The temperature can reach the highest about 2000 degree celsius in the upper thermosphere. The weather events like northern lights, southern lights, aurora, etc. happen in this layer.
This layer of the atmosphere is also called the Ionosphere due to the availability of electrically charged particles. It also protects Earth from falling of any meteorites like celestial bodies as it burns up them. This layer reflects back the radio waves to the Earth which are transmitted from the Earth. It is to be noted here that satellites launched from Earth orbit Earth in this layer only.
5. Exosphere
The Exosphere is the topmost layer of Earth’s atmosphere which lies above the Ionosphere. It extends from the ground level to 10,000 Km in height. The air density is lesser in this layer and the temperature reaches up to 5568°C. It is a very close layer to outer space. Lighter gaseous particles of hydrogen and helium move into outer space and make air density lesser here. There is no distinct upper layer of the exosphere but we consider the imaginary line of exopause to separate the exosphere from outer space.