Atmosphere

Atmosphere

Atmosphere
1. The mixture of gases surrounding the Earth
Different layers of the atmosphere
1. Stratosphere (Stratopause
  1. The layer of the atmosphere above the troposhere
  2. Temperature does not decrease with increasing altitude
  3. Free of cloud and dust, ozone absorbs and filters out UV radiation
2. Thermosphere
  1. The outermost layer of the Earths surface
  2. Temperature falls with increasing altitude
3. Mesosphere
  1. The layer of atmosphere above the stratosphere to an altitude of about 80km above the surface of the Earth
4. Troposphere (Tropopause)
  1. Layer extending approx. 8- 17km upwards from Earths surface
  2. Temperature decreases with increasing height
    1. Temp usually decreases at av. 6.5C per km
  3. Most of our climae and weather processes happen here
Atmospheric heat budget
1. depends on the balance between incoming solar radiation (insolation) and outgoing radiation from the planet
Planteray surface winds
1. Wind is the horizontal movement of air on the Earth's surface
2. Winds result in differences in air pressure - always blow from high to low
  1. If temp. increases in a place the air expands and rises, which reduces air pressure
    1. If temp. decreases in a place the air becomes denser and sinks which increases air pressure.
3. Surface winds change seasonally and are affected by land and sea
Atmospheric pressure and winds
1. The pressure exerted by the weight of the air in the atmosphere at the surface of the Earth
2. Av. pressure at sea level is 1,013mb.
3. Ground surface has greatest weight acting upon them - so pressure is greatest here.
4. High pressure - air is descending and associated with dry weather
5. Low pressure - air is rising and associated with precipitation and windy conditions. As it ascends air cools and cannot hold as much water vapour - so condenses and become clouds and condensation level.
General atmospheric circulation system
1. The differential heating of the Earth's surface by the sun is sufficient to create a pattern of pressure cells.
  1. Movement within each cell is usually circular and responsible for the transfer of surplus energy from equatorial regions to other parts of the Earth
2. Rossby waves - A series of large waves that occur in the westerlies in the mid-latitudes in both Northern and Southern hemispheres
3. Hadley Cells - form the basis of tropical air circulation, and are responsible for seasonal changes in climate
  1. Between the 2 Hadley cells there is an area of low pressure known as the Inter Tropical Convergence Zone (ITCZ
    1. Sun is always high, ground heated rapidly by day and lots of surface evaporation. Hot air rises in convection currents and area of low pressure develops
      1. This rising air cools and water vapour condenses giving heavy rainfall
  2. At high altitudes the air moves polewards - usually circulating as upper westerly wind as a result of the Coriolis
4. Ferrel and Polar cells

Nächster

Beschreibung

Zusammenfassung der Ressource

ähnlicher Inhalt

	Erstellt von nicolaglass vor fast 10 Jahre