The atmosphere

The atmosphere

1. DEFINITION

   • Layer of gases that surrounds the Earth

2. ORIGIN

   • 4.4 BY
     • Gases escaped from deep inside
     • Hydrogen & Helium
     • Blew away by solar wind
   • Primitive atmosphere
     • Volcanic gases
     • Thanks to magnetic field
   • 3.5 BY
     • Photosynthetic bacteria produced Oxygen

3. COMPOSITION

   • Primitive atmosphere
     • Volcanic gases
       • Carbon dioxide
       • Chlorine & Sulphur oxides
       • Small amounts: nitrogen & argon
   • Today
     • Oxigen 21%
     • Nitrogen 78%
     • Trace gases 1%
       • Argon 0.9%
       • Carbon dioxide
       • Other gases 0.06%
         • Methane Chorine & Sulphur oxides Ozone

4. STRUCTURE

   • Troposphere
     • Lowest layer Closest to Earth
     • 90% mass
     • To -55ºC
     • Weather
     • Tropopause 10-15 km
   • Stratosphere
     • Very stable vertically
     • 10-50km
     • Planes
     • Strong horizontal winds
     • Contains Ozonosphere
     • Stratopause
   • Mesosphere
     • 50-80km
     • Temperature reaches -100ºC
     • Mesopause
   • Ionosphere
     • Outer layer
     • At 500 km meets outer space
     • Less and less air
     • Higher temperatures

5. FUNCTIONS

   • Provides to living things:
     • Oxygen to breath
     • Carbon dioxide used in photosynthesis
     • Nitrogen used by some bacteria
     • Filter against solar radiation
     • Regulation of global temperature
   • Other functions
     • Winds
       • Distribute solar energy
       • Change landscape through erosion, transport and sedimentation
     • Changes/breaks rocks
       • Through chemical reactions
       • Through temperature variations

6. CHARACTERISTICS

   • Atmospheric pressure
     • Weight of air
     • Depends on altitude & temperature
     • Measured with a barometer
   • Air movement
     • Wind
       • Mass of air that moves
       • Caused by atmospheric pressure differences
     • Air mass
       • Large volume of air with similar properties
       • Fronts
         • Boundary between masses
         • Warm front
         • Cold front
       • Areas
         • High pressure area
           • Air fails & moves away in all directions
         • Low pressure area
           • Air enters from all directions & rises
   • Precipitation
     • Any form of water that falls to Earth
     • At very low temperatures: Snow or hail
   • Weather
     • Conditions of the atmosphere in a specific area at a particular time
   • Air pollution
     • Air quality: state of air at a given time
     • Pollutants
       • Substances that affect negativity air quality
       • Examples
         • Carbon monoxide
           • Causes suffocation
         • Sulphur & nitrogen oxides
           • Irritant & Acid rain
         • Soot
           • Particles, enter lungs & blood, causing serious damage
       • Solid, liquid or gas
     • Problems
       • Global warming
         • Carbon dioxide
           • Human activities
             • Increases Acumulates
               • Green house effect
                 • Traps heat energy emitted by Earth
           • Natural component of air
       • Hole in the ozone layer
         • CFC gases
           • Produced by industry
           • If they reach stratosphere, destroy ozone
   • Clouds
     • Water droplets
       • Very light
       • Air rises
   • Climate
     • Average atmosphere conditions in a specific area over a long period of time
     • Meteologists
       • Study average daily values over a long period:
         • Temperature
         • Precipitation
       • Create climographs
   • Favorable actions