Structure of the Atmosphere
The structure of the atmosphere is classified into the following layers:
- Troposphere: 0 to 12 km
- Stratosphere: 12 to 50 km
- Mesosphere: 50 to 80 km
- Thermosphere: 80 to 700 km
- Exosphere: 700 to 10,000 km
The structure of the atmosphere
- The troposphere is the closest to the Earth’s surface and contains water vapor (clouds), moisture, dust,
- Most of the weather phenomena take place in
- Temperature decreases with altitude in the Troposphere.
- Height of the Troposphere varies i.e. at the equator, it is measured about 18 km and at the poles, it is 12
- The tropopause is the transitional zone that separates Troposphere and Stratosphere.
- The stratosphere is the second-lowest layer of the Earth’s Atmosphere that goes up to 50
- The stratosphere contains Ozone (O3) Layer that absorbs the ultraviolet rays(coming through the Sun rays) and protects life on the
- As the ultraviolet radiation absorbs in Stratosphere, therefore the temperature rises with increasing
- Stratopause is the transitional zone that separates Stratosphere and Mesosphere.
- Mesosphere, present above the Stratosphere, extends up to (from 50 km to) 80
- The temperature in the Mesosphere decreases with increasing
- Menopause is the transitional zone that separates Mesosphere and Thermosphere.
- Above the Mesosphere, Thermosphere is the second-highest layer that starts at the altitude of 80 km and extends up to (roughly) 700 km (however, it varies between 500 and 1000 km).
- The lower part of the Thermosphere (roughly between 80 km and 550 km) contains ions and known as the Ionosphere.
- The temperature of the Thermosphere rises with increasing
- Thermopause is the transitional zone that separates Thermosphere and Exosphere.
- The exosphere is the highest or outermost layer of the Earth’s atmosphere that extends (starting from 700 km altitude) up to 10,000 km where it ultimately merges into the solar wind.
- Major constituents of the Exosphere are helium, hydrogen, nitrogen, oxygen, and carbon dioxide.
- The phenomena of Aurora Borealis and Aurora Australis can be seen in the lower part of the Exosphere (merged with the upper part of the Thermosphere).
- The Satellite (orbiting the Earth) is normally placed in the Exosphere (as shown in the image given above).
- The composition of the Earth’s atmosphere changes with the
- The major constituents of the Earth’s atmosphere are:
- Oxygen – 95%
- Nitrogen – 09%
- Argon – 93%
- The pressure exerted by the weight of air at a given point is known as “Atmospheric Pressure” or “Barometric Pressure.”
- With increasing altitude, the atmospheric pressure decreases.
- On average, a column of air (which is normally one square centimeter in cross-section), measured at the sea level, has a weight of about 1.03 kg (about 10.1 N).
- The Average Air Pressure is about 14.70 pounds per square inch, (equivalent to 1,013.25 × 103 dynes per square centimeter or 1,013.25 millibars) at the sea level.
- A visible mass of condensed vapor floating above the general level of the ground is known as Cloud.
- Based on the altitude, the cloud is classified as:
- High Altitude Cloud: For example, Cirrus, Cirrocumulus, & Cirrostratus.
- Middle Altitude Cloud: For example, Altostratus and Altocumulus.
- Low Altitude Cloud: Stratus, Stratocumulus, Cumulus, and Nimbostratus (it can be also seen in the middle altitude).
- Vertical: Cumulonimbus
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