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Earth’s Atmosphere: Key Components & Composition of Atmosphere

November 30, 2023 1356 0

Earth’s Life-Sustaining Atmosphere

The earth is the only planet which has life. The surface of the earth is a complex zone which has three main components of the environment viz. Lithosphere, Hydrosphere and Atmosphere. These 3 meet, overlap and interact and form a narrow zone called a Biosphere which sustains life. Along with land and water, air is a main part of this biosphere which plays a major role in regulating atmospheric activities. In this chapter, we will deal primarily with this composition of atmosphere and its major components. 

Word Origin

In the Greek language, Lithos means Stone; Atmos means Vapour; Hudor means Water; and Bios means Life.

Atmosphere: A Journey Through the Layers and Composition of Atmosphere

Biosphere

  • Composition of Atmosphere: The Composition of Atmosphere  is a gaseous layer surrounding the earth, which comprises a mixture of gases, water vapour, and dust particles
  • Notably, 99% of the composition of the atmosphere’s total mass is concentrated within a range of 32 kilometres from the Earth’s surface. 

Composition of Atmosphere: Atmosphere’s Blueprint

Composition of Atmosphere

 Composition of Atmosphere

  • Composition of Gases: The Composition of Atmosphere consists mainly of Nitrogen(78%) and Oxygen(21%) and other gases . 
    • Nitrogen is essential for plant growth and Oxygen is indispensable for humans and animals for survival. 
    • At an altitude of 120 kilometers, oxygen becomes almost negligible.
  • Carbon Dioxide and the Greenhouse Effect: Carbon dioxide, another critical gas, regulates Earth’s temperature and is transparent to incoming solar radiation but acts as a greenhouse gas, contributing to the greenhouse effect. 
    • In recent decades, carbon dioxide levels have been on the rise, mainly due to the burning of fossil fuels. 
  • Protective Ozone Layer: Ozone, located between 10 and 50 kilometers (stratosphere) above the Earth’s surface, plays a crucial role in absorbing harmful ultraviolet rays from the sun. 
    • This ozone layer acts as a protective shield, safeguarding life on Earth.
  • Particulate Matter: The Composition of Atmosphere also contains dust particles, including sea salts, fine soil, smoke-soot, ash, pollen, and dust from disintegrated meteors
    • Dust particles are more concentrated in subtropical and temperate regions due to dry winds. 

Additional Information

Increased CO2 levels, from sources like factory emissions and car fumes, cause global warming by intensifying heat retention. This leads to the melting of polar ice, rising sea levels and causing coastal floods. Such drastic climate changes can lead to the extinction of certain plant and animal species over time.

Atmospheric Layers: Earth’s Air in Five Distinct Zones

Layers of Atmosphere

The Composition of Atmosphere is divided into distinct layers, each with its own characteristics .

  1. Troposphere: Earth’s Dynamic Weather and Life Zone
    • It is the lowest layer with an average height of 13 kilometres.
    • It extends up to approximately 8 kilometres near the poles and about 18 kilometres at the equator. 
    • All weather changes and biological activities occur in this layer. 
    • In the Troposphere, temperature decreases at a rate of 1°C for every 165 metres of height.
  1. Stratosphere: Guardian of Life with the Ozone Shield
    • It is located above the tropopause, and extends to a height of 50 kilometres. 
    • It contains the ozone layer, which absorbs harmful ultraviolet radiation from the sun, protecting life on Earth.
  1. Mesosphere: Cold Depths and the Mesopause Boundary
    • It extends up to 80 kilometres, and is characterised by decreasing temperatures with altitude, reaching as low as minus 100°C at its upper boundary, known as the mesopause.
  1. Ionosphere: Electric Heights and Radio Wave Reflection
    • This region spans from 80 to 400 kilometres above the mesopause. 
    • It contains electrically charged particles called ions and reflects radio waves back to Earth.
  1. Exosphere: Earth’s Boundary with the Cosmos Beyond
    • It is the uppermost layer of the Composition of Atmosphere , where the atmosphere gradually merges with outer space. 
    • This layer contains extremely rarefied contents.

Weather Instruments

Weather Instruments

Weather and Climate: Daily Changes and Long-Term Patterns

  • Definition: Weather is the day-to-day condition of the atmosphere, affecting our daily lives and activities.
  • Components:  It can change dramatically and includes factors like temperature, air pressure, wind, and humidity.
  • Climate, on the other hand, represents the long-term average weather patterns of a place.
    • Studies related to weather and climate help us plan and adapt to changing conditions.

Do you know?

The standard unit of measuring temperature is degree Celsius. It was invented by Anders Celsius. On the Celsius scale the water freezes at 0°C and boils at 100°C.

Temperature: Diurnal, Seasonal, and Urban Impacts

  • Temperature indicates the degree of hotness or coldness in the air.
  • Diurnal and Seasonal Variation:  It varies between day and night and from season to season, with summers being hotter than winters.
  • Insolation: The incoming solar energy affects temperature distribution, decreasing from the equator to the poles.
  • Urban Heat Islands:  Urban areas, compared to villages, have higher temperatures due to buildings and roads absorbing heat.

Do you know? 

When air is heated, it expands, becomes lighter and goes up. Cold air is denser and heavy. That is why it tends to sink down. When hot air rises, cold air from the surrounding area rushes there to fill in the gap. That is how air circulation takes place.

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 Final Result – CIVIL SERVICES EXAMINATION, 2023.   Udaan-Prelims Wallah ( Static ) booklets 2024 released both in english and hindi : Download from Here!     Download UPSC Mains 2023 Question Papers PDF  Free Initiative links -1) Download Prahaar 3.0 for Mains Current Affairs PDF both in English and Hindi 2) Daily Main Answer Writing  , 3) Daily Current Affairs , Editorial Analysis and quiz ,  4) PDF Downloads  UPSC Prelims 2023 Trend Analysis cut-off and answer key

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 Final Result – CIVIL SERVICES EXAMINATION, 2023.   Udaan-Prelims Wallah ( Static ) booklets 2024 released both in english and hindi : Download from Here!     Download UPSC Mains 2023 Question Papers PDF  Free Initiative links -1) Download Prahaar 3.0 for Mains Current Affairs PDF both in English and Hindi 2) Daily Main Answer Writing  , 3) Daily Current Affairs , Editorial Analysis and quiz ,  4) PDF Downloads  UPSC Prelims 2023 Trend Analysis cut-off and answer key

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Quick Revise Now !
UDAAN PRELIMS WALLAH
Comprehensive coverage with a concise format
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Designed as per recent trends of Prelims questions
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