Key Points

Composition and Structure of Atmosphere

28 Sections
  • Definition of the Atmosphere

    The atmosphere is a mixture of different gases that envelopes the Earth all around. It is an integral part of the Earth's mass, with 99 percent of its total mass confined to the height of 32 km from the surface.

  • Definition of Atmosphere

    The atmosphere is a mixture of different gases that envelopes the Earth all around. It is essential for survival, providing life-giving gases like oxygen for animals and carbon dioxide for plants.

  • Composition of the Atmosphere

    The atmosphere is composed of three main components: gases, water vapour, and dust particles. The proportion of these components can change with altitude.

  • Composition of the Atmosphere

    The atmosphere is composed of three main elements: gases, water vapour, and dust particles. The proportion of these components varies with altitude and location.

  • Role of Carbon Dioxide

    Carbon dioxide is transparent to incoming solar radiation but opaque to outgoing terrestrial radiation. It absorbs Earth's heat and is largely responsible for the greenhouse effect.

  • Role of Carbon Dioxide

    Carbon dioxide is transparent to incoming solar radiation but opaque to outgoing terrestrial radiation. It absorbs terrestrial radiation and reflects some back, causing the greenhouse effect.

  • Importance of the Ozone Layer

    Ozone is found between 10 and 50 km above the surface and acts as a filter. It absorbs harmful ultra-violet rays from the sun, protecting life on Earth.

  • Importance of the Ozone Layer

    Ozone is found between 10 and 50 km above the surface and acts as a filter. It absorbs harmful ultraviolet rays from the sun, preventing them from reaching the Earth's surface.

  • Function of Water Vapour

    Water vapour is a variable gas that absorbs parts of solar radiation and preserves Earth's radiated heat. It acts like a blanket, preventing the Earth from becoming too hot or too cold.

  • Function of Water Vapour

    Water vapour is a variable gas that absorbs parts of solar insolation and preserves Earth's radiated heat. It acts like a blanket, moderating temperatures and contributing to atmospheric stability.

  • Role of Dust Particles

    Dust particles act as hygroscopic nuclei, which are surfaces around which water vapour condenses to form clouds. They are generally concentrated in the lower layers of the atmosphere.

  • Role of Dust Particles

    Dust and salt particles act as hygroscopic nuclei. Water vapour condenses around these particles to form clouds and precipitation.

  • Structure of the Atmosphere

    The atmosphere is divided into five distinct layers based on temperature variations. These layers are the Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere.

  • Five Layers of the Atmosphere

    The atmosphere is divided into five distinct layers based on temperature conditions. From the ground up, they are the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

  • The Troposphere: Weather Layer

    The troposphere is the lowermost layer, extending to an average height of 13 km. All changes in climate and weather occur in this layer, and it is the most important for all biological activity.

  • The Troposphere Layer

    The troposphere is the lowermost layer, with an average height of 13 km. All weather changes and biological activities occur in this layer, and temperature decreases with height.

  • The Stratosphere and Ozone

    The stratosphere is found above the troposphere and extends up to a height of 50 km. Its most important feature is the presence of the ozone layer, which absorbs ultraviolet radiation.

  • The Tropopause

    The tropopause is the boundary zone that separates the troposphere from the stratosphere. The air temperature at the tropopause is nearly constant.

  • The Mesosphere: Coldest Layer

    The mesosphere lies above the stratosphere and extends up to 80 km. In this layer, temperature decreases with increasing altitude, reaching as low as minus 100 degrees Celsius.

  • The Stratosphere Layer

    The stratosphere is found above the tropopause and extends up to 50 km. Its most important feature is the presence of the ozone layer, which absorbs UV radiation.

  • The Mesosphere Layer

    The mesosphere lies above the stratosphere and extends up to a height of 80 km. In this layer, temperature again decreases with increasing altitude.

  • The Thermosphere and Ionosphere

    The thermosphere is located between 80 and 400 km and contains electrically charged particles known as ions, forming the ionosphere. This layer reflects radio waves back to Earth.

  • The Thermosphere (Ionosphere)

    Located between 80 and 400 km, this layer contains electrically charged particles called ions and is known as the ionosphere. It reflects radio waves back to Earth, enabling wireless communication.

  • The Exosphere: Outermost Layer

    The exosphere is the uppermost layer of the atmosphere. The contents in this layer are extremely rarefied, and it gradually merges with outer space.

  • The Exosphere Layer

    The exosphere is the uppermost layer of the atmosphere. It is extremely rarefied and gradually merges with outer space.

  • Gas Distribution at Altitude

    The proportion of gases changes in the higher layers of the atmosphere. Oxygen becomes almost negligible at a height of 120 km, while carbon dioxide and water vapour are found only up to 90 km.

  • Elements of Weather and Climate

    The main elements of the atmosphere that influence human life are temperature, pressure, winds, humidity, clouds, and precipitation. These elements are subject to constant change.

  • Elements of Weather and Climate

    The main elements of atmosphere that are subject to change and influence human life are temperature, pressure, winds, humidity, clouds, and precipitation.

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