Docstoc

APES Atmosphere PPT _1

Document Sample
APES Atmosphere PPT _1 Powered By Docstoc
					APES Atmosphere PPT #1
        Earth’s Atmosphere
          Characteristics
• Weather is the state of the atmosphere at a
  given time and place. It is constantly changing




• Climate is weather patterns occurring over many
  years. It helps describe a place or region.
• Measurable properties of weather and
  climate are:

  – Air temperature
  – Humidity
  – Type and amount of precipitation
  – Air pressure
  – Speed and direction of the wind
           Atmosphere Composition
• Continually exchanges
  materials with the
  oceans of the Earth
  – “Air” is a mixture of
    different gases
     •   78% Nitrogen
     •   21% Oxygen
     •   0.93% Argon
     •   0.039% Carbon Dioxide
     •   Some Water vapor
     •   Some dust particles
     •   Some ozone
– Water Vapor:
   • Source of all clouds and
     precipitation
   • Absorbs heat and some
     solar energy



– Dust Particles:
   • Includes: sea salt, fine
     soil, smoke and soot
     from fires, pollen and
     microorganisms and
     ash and dust from
     volcanic eruptions.
     Ozone: a form of oxygen

• Concentrated in a layer 10-
  50 kilometers above the
  Earth’s surface
• O2 splits into O when they
  absorb the sun’s UV rays
• O + O2 and a catalyst = O3
• Crucial to life on Earth
  because it absorbs UV
  radiation from the sun
Air Pollutants
     Structure of the Atmosphere

• The atmosphere thins
  quickly as altitude
  increases.

• Atmospheric pressure
  is the weight of the air
  above, so the
  pressure decreases
  as the altitude
  increases.
• Temperature:
  – the atmosphere is divided into 4 layers
    based on temperature changes as
    altitude increases:

  –   Troposphere
  –   Stratosphere
  –   Mesosphere
  –   Thermosphere
– Troposphere: bottom
  layer; weather
  happens here;
  temperature continues
  to drop up to 12
  kilometers (7.2 miles)

– Tropopause: outer
  boundary of the
  troposphere
– Stratosphere:
  temperature remains
  constant then
  increases up to 50
  kilometers (30 miles);
  ozone is located here.

– Stratopause: outer
  boundary of the
  stratosphere
– Mesosphere:
  Temperatures
  decrease up to 80
  kilometers (48 miles)



– Mesopause: outer
  boundary of the
  mesosphere
• Thermosphere:
  Temperatures
  increase; no defined
  upper limit.
Part 2: Heating the Atmosphere
 Temperature: the
  average kinetic
  energy of the
  molecules in a
  substance

 Heat: energy
  transferred from one
  object to another due
  to temperature
  differences
Three (3) Methods of heat Transfer:
             Conduction
             Convection
              Radiation
                         Conduction:
• Heat moves when molecules
  touch each other to pass it
  on.
       Heat flows from the higher
        temperature matter to the
        lower temperature matter.
       Conduction is important only
        between Earth’s surface and
        the air in direct contact with
        the surface.
       For the whole atmosphere,
        conduction is the least
        important mechanism for
        heat transfer.
Convection:
 • Heat moves by mass
   movement or circulation
   within a substance.
       For the whole atmosphere,
        much of the heat transfer
        occurs because of
        convection.

       Convection occurs in liquids
        (ocean and air) and in
        pseudo-solids (Earth’s
        mantle)
Radiation:
• Heat moves in waves
  in all directions

• Does not need a
  substance to move
  through (unlike
  conduction and
  convection)
    Four (4) Laws of Radiation:

 All objects, at any temperature, emit
  radiant energy
 Hotter objects radiate more total energy
  per unit area than colder objects do.
 The hottest radiating bodies produce the
  shortest wavelengths of maximum
  radiation
 Objects that are good absorbers of
  radiation are good emitters as well.
   Three (3) results when radiation
          strikes an object:
 Reflected: light
  materials reflect.
  Light bounces back
  with the same
  intensity
    High Albedo


 Scattered: more
  light rays with a
  weaker intensity.
Three (3) results when radiation
       strikes an object:
    Absorbed: dark materials absorb the
     radiant energy and converts into heat
       Low Albedo

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:124
posted:7/18/2011
language:English
pages:22