Topic 2 - Atmosphere


LAYERS OF THE ATMOSPHERE

  • The Earth’s atmosphere is an envelope of gasses, commonly known as air, retained by the earth’s gravity and is vertically extended and can be divided into the following layers:

    • Troposphere

    • Stratosphere

    • Mesosphere

    • Thermosphere

    • Exosphere


WHY IS THE ATMOSPHERE DIVIDED INTO 5 DIFFERENT LAYERS?

  • The atmosphere is divided into five different layers because the atmosphere is not uniform, it's properties change with altitude and 

  • Two properties change with altitude, the AIR PRESSURE and the AIR TEMPERATURE.


TROPOSPHERE

  • The troposphere is the layer of the atmosphere nearest to earth. 

  • The only layer of the atmosphere where life is possible.

  • The troposphere goes from 0 km to 16km.

  • All weather happens in the troposphere.

  • More than half the air in the total atmosphere is in this layer.

  • The temperature drops as the altitude increases.

  • Harmful ozone is found here.

  • Atmospheric Gasses:

    • Nitrogen, oxygen, argon, water vapor, carbon dioxide, and most other gasses are invisible.

    • Ground based smog, which is visible, contains reactants of nitrogen and ozone.


  • Extends up to 8 kilometers in height, this is the lowest and densest layer. The temperature here decreases with altitude bounded by land or sea surface below and by tropopause above.



GREENHOUSE EFFECT

  • Some of the gasses in the earth’s atmosphere are called greenhouse gasses (GHGs) because of their special ability to let sunlight pass through the atmosphere, but prevent that heat from leaving the atmosphere, thus causing a phenomenon called the natural greenhouse effect. 

  • This is a good thing because it makes the temperature not too cold nor too hot therefore making our planet livable. If there was no greenhouse effect, the earth would have an average temperature of –18°C or about 0°C. 

  • The following are the greenhouse gasses and their natural sources: 

  1. Water vapor (H2O), the most abundant natural greenhouse gas, acts as natural feedback.

  2. Carbon dioxide (COs) is released naturally through respiration and volcanic eruptions.

  3. Methane (CH4) is a gas produced naturally by wetlands, through agriculture activities, digestion in ruminants, and decomposition of wastes in landfills,

  4. Nitrous oxide (N2O) is generated by soil cultivation processes and the use of organic fertilizers


WATER ON EARTH

  • The condition is just right!

  • The combination of three factors: Distance to the Sun, the albedo, and the greenhouse effect, make it possible for water to stay on Earth.

  • N2 and O2 are not greenhouse gasses.

  • Not much CO2 in the atmosphere.

  • Variable amount of H2O in the atmosphere...regulated by the temperature.The result is a mild greenhouse effect...not too hot, and not too cold, just the right temperature for most of the water to stay in liquid phase, and some to stay in gas phase in the atmosphere on the surface of the Earth…


OZONE

  • A gaseous layer in the upper atmosphere that protects the earth from harmful ultraviolet radiation. At lower levels, ozone becomes a major pollutant.

  • Two types of Ozone: Stratosphere (good) and Troposphere (bad)


SMOG

  • Pollution formed by the interaction of pollutants and sunlight reactions (photochemical smog),usually restricted visibility, and occasionally hazardous to health.


STRATOSPHERE

  • The stratosphere goes from 16 km to 50 km.

  • The temperature goes up with altitude.

  • Most jets fly in this layer but not birds

  • The protective ozone is at the top of the atmosphere(It protects us from the ultraviolet radiation of the sun.)

  • Rivers of air, called Jet Streams,can be found at the base of this layer.


  • From 9 to 50 kilometers in height, the temperature here increases up to 900°C with height. It is limited above by the stratopause. In the stratosphere, short wavelength ultraviolet energy is absorbed by ozone, causing the air to be heated.


MESOSPHERE

  • The Mesosphere goes from 50 km to 90km.

  • In the mesosphere, the temperature drops with altitude.

  • The mesosphere is the coldest layer of the atmosphere.

  • Meteors burn up in this layer.


THERMOSPHERE

  • The thermosphere goes from 90 km to 300 km.

  • In the thermosphere the temperature goes up with altitude.

  • The thermosphere is the hottest layer of the atmosphere.

  • Curtains of light called auroras occur in this layer. 

    • The Ionosphere is found in thethermosphere. This is the component of the thermosphere that makes the auroras.Charged particles, called IONS, are found in this layer.

    • Radio waves are sent from Earth and reflected back by this layer with satellites.


IONOSPHERE

  • Upperpart of the thermosphere (has many atoms split into ions, reflects radio waves back to Earth)


EXOSPHERE

  • The exosphere is the outermost layer of the atmosphere.

  • The temperature in the exosphere goes up with altitude.

  • Satellites orbit earth in the exosphere.



This Act establishes a comprehensive air pollution control policy for the country by preserving and protecting air quality, establishing an air quality management system, prohibiting certain forms of waste disposal, and regulating emissions.