Atmosphere Contents

Contents

Structure and composition

  1. Aims
  2. The atmosphere is the layer of air which blankets the Earth; it is made up of a number of gases
  3. The predominant gases in the atmosphere are nitrogen, oxygen, argon and carbon dioxide
  4. Aerosols are small particles of matter suspended in the atmosphere
  5. Physically, the atmosphere has a clearly defined vertical structure
  6. The lowest of the layers in the atmosphere is called the troposphere
  7. The tropopause separates the troposphere from the rest of the atmosphere
  8. The stratosphere is above the troposphere, extending to 50 km
  9. Interactions can occur between the stratosphere and the troposphere
  10. There are various further layers of the atmosphere
  11. The total quantity of carbon in the global environment is immense
  12. The most active component of the carbon cycle is atmospheric carbon dioxide
  13. The carbon cycle drives 'global warming'
  14. Oxygen is essential for animal life in the oceans and on land
  15. There should be a global balance of oxygen and carbon dioxide in the atmosphere

Solar Energy

  1. Aims
  2. The Earth is isolated
  3. The sun is immensely hot
  4. Solar radiation plays many crucial functions
  5. There are two alternative theories of how radiation and light travel
  6. Wave theory and photon theory are each valid in particular circumstances
  7. Light can be split into a spectrum
  8. Colours correspond with particular wavelengths
  9. The photon theory of radiation can be formulated mathematically
  10. The photon is to radiation what the molecule is to substances
  11. The amount of energy in light is measurable
  12. Only 45% of the incoming solar radiation reaches the surface of the Earth
  13. The laws of thermodynamics govern energy transformations

Energy variations

  1. Aims
  2. The amount of solar radiation received by the Earth varies with distance from the sun
  3. The shape of the Earth's orbit changes over periods of about 100,000 years
  4. The Earth as a whole currently receives less sunlight during June than December
  5. The amount of solar radiation received by the Earth varies with distance from the equator
  6. The Earth's obliquity (tilt) affects the amount of radiation received at different places
  7. The combined effect of obliquity (tilt) and eccentricity modifies radiation input over a year
  8. There are variations over time in the angle of tilt of the Earth
  9. Precession causes variations in solar radiation
  10. Precession alters the distribution of radiation across the surface of the Earth
  11. The average temperature of the Earth is roughly constant, and a surplus of radiation at the equator is balanced by a deficit at the poles
  12. A redistribution of the Earth's energy is continually occurring

Energy budgets

  1. Aims
  2. Many factors influence the amount of solar radiation reaching the Earth's surface
  3. Incoming and outgoing energy flows in the Earth's atmosphere are roughly in balance
  4. There are spatial and temporal variations in the amount and spectral composition of solar radiation reaching the Earth's surface
  5. Radiation absorbed by the Earth influences climate
  6. The albedo of different surfaces varies considerably
  7. The solar constant is the amount of solar radiation which reaches the outer atmosphere
  8. The atmosphere is analogous to a greenhouse
  9. Human activities are augmenting the natural greenhouse effect
  10. A limited number of factors are responsible for natural climate change
  11. The oceans have an impact on atmospheric carbon dioxide
  12. There is a connection between volcanic eruptions and short term climate change
  13. Two large volcanic eruptions in the last century have had an effect on climate
  14. The sun's energy output may be more variable than first thought
  15. Sunspots have been linked to climate change

General circulation

  1. Aims
  2. The general circulation of the atmosphere refers to the average of wind patterns on a global scale
  3. There are distinct characteristics of the general circulation at low-latitudes
  4. As the air moves poleward from the tropics it constantly cools by radiation
  5. There are cellular circulations of air in each hemisphere near the equator, known as Hadley Cells
  6. Polar fronts form at mid-latitudes
  7. Rossby waves occur in mid latitudes
  8. Jet streams form at higher altitudes in the mid latitudes
  9. There are weak polar cells at high latitudes
  10. El-Niño is caused by warming and cooling of the Pacific Ocean
  11. El-Niño is a locally generated phenomenon affecting the whole world

Secondary circulation

  1. Aims
  2. An air mass is an extremely large body of air
  3. The middle latitudes is a transition zone marked by weather fronts
  4. Extra-tropical cyclones (mid-latitude depression systems) are areas of low pressure
  5. Tropical cyclones are intense low-latitude depression systems which form over oceans
  6. The exact mechanisms for production and growth of hurricanes are not well understood
  7. From thunderstorms to hurricanes
  8. There are several differences between a hurricane and a mid-latitude storm
  9. Tornadoes are areas of intense low pressure which occur over land
  10. Tornadoes have the power to lift very large objects

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