5 Layers of the Atmosphere in Order

In this 5 layers of the atmosphere in order post we have briefly explained about 5 layers of the atmosphere Troposphere, Stratosphere, Mesosphere, Ionosphere, and Anthrosphere.

5 Layers of the Atmosphere in Order

This article discusses the five major Zones of the atmosphere. The Zones of the atmosphere are as follows:

Troposphere,

Stratosphere,

Mesosphere,

Ionosphere, and

Anthrosphere.

Zones of the atmosphere

5 Layers of the Atmosphere in Order. Image Source: www.pas.rochester.edu

Troposphere

The troposphere is considered to be the lowest layer of the Earth’s atmosphere. The bulk (about 75-80 percent) of the atmosphere lies located in the troposphere. The majority of the types of clouds are located in the troposphere and the majority of weather happens in this layer. The troposphere is the moistest layer in the atmosphere. All the layers above have the least amount of moisture.

The troposphere’s bottom is on the earth’s surface. The troposphere extends up to around 10 kilometres (6.2 miles or 33,000 feet) above sea level. The top of the troposphere is different according to the latitude (it is the lowest at the poles and the highest near an equator) and also by seasons (it will be lower during winter and higher during summer). It could be up to 20 kilometres (12 miles or 65,000 meters) near the equator but as small as (4 miles, or 23,000 feet) across the poles during winter.

The warmest air is at the bottom of troposphere close to ground level. The temperature of air decreases as it moves upwards in the troposphere. This is why the summits of mountains that are tall can be snow-covered in summer. The density and pressure of the air decreases as you increase the altitude. The layer that is immediately above the troposphere is known as stratosphere. The line that separates the stratosphere and the troposphere is referred to as “tropopause”.

Stratosphere

The region that is above the tropopause is referred to as the stratosphere (11 miles to 50 kilometers) with temperatures that between -56⁰C and -2⁰C). In this zone, the temperature-altitude curve shows a warming trend with increasing altitude, i.e., it exhibits a negative lapse rate. The stratosphere’s ozone acts as a shield to protect Earth’s inhabitants from the harmful UV rays from the sun and, in turn providing the heat source to separate the stratosphere and the turbulent troposphere.

The area above the stratosphere (>50 kilometers) is referred to as the stratopause. Because of the absorption by ultraviolet radiation, the stratosphere is heated up, causing temperatures to invert, which hinders the vertical mixing of pollutants. This is why the smog appears to be hanging in industrial areas. Smog is spread horizontally quickly, but it does so very slowly vertically.

Mesosphere

Mesosphere (literally middle sphere) is the 3rd highest layer in the atmosphere. It is comprising a region of 50 to 80 kilometres from the surface of Earth and above it the troposphere and stratosphere and beneath the thermosphere. This layer is separated from stratosphere through the stratopause, and separated from the thermosphere through the mesopause.

Temperature within the mesosphere decrease with increasing altitude, dropping to 100⁰C. The mesosphere is the coldest layer of all the atmosphere’s layers. Actually, it’s more frigid than Antarctica’s coldest temperature ever recorded. It’s cold enough that it can make in water vapour into clouds of ice. They can be observed when sunlight hits them at sunset. They are referred to as Noctilucent Clouds (NLC). NLCs are the most seen at times when the Sun is between 4 and 16 degrees lower than the Horizon.

The mesosphere is also the area that a large number of meteors are able to burn when they enter the atmosphere of Earth. When seen from the Earth they appear in the form of shooting stars.

Ionosphere

Thermosphere is the region (85 km to 500 km, temperature ranges from -92⁰C to 1200⁰C) above mesopause, where temperature rises rapidly with increasing altitude, exhibiting a negative lapse rate. The gases present in this region (O2 and NO) absorb solar radiation and undergo ionisation.

The region above the stratosphere, in the altitude range of 50 km to 100 km, is called ionosphere. In this region, O2+, O+, NO+ and electrons exist at significant levels. Atmosphere above the ionosphere is called exosphere or outer space. It extends up to 32190 km from the earth’s surface. It lacks atmosphere and consists of only H and He.

Anthrosphere

Anthrosphere constitutes the fifth sphere of the environment along with the geosphere, hydrosphere, atmosphere and biosphere. It consists of things humans construct and use.

Further Readings