Higher Atmosphere Revision

  • 10,605 views
Uploaded on

 

More in: Technology , Education
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
  • really helpful !!
    Are you sure you want to
    Your message goes here
  • its wonderful presentation , but i want to download it but how
    Are you sure you want to
    Your message goes here
  • gr8 presentation can i get the presentation downloaded so thay i can use in class 9 in india
    Are you sure you want to
    Your message goes here
  • Wonderful presentation - would love to be able to download a copy to show my 6th form geography students as this site is (for some crazy reason) blocked in my school.
    Are you sure you want to
    Your message goes here
  • i want to download this presentation .... how can i download this file ?? please anyone tell me ??
    Are you sure you want to
    Your message goes here
No Downloads

Views

Total Views
10,605
On Slideshare
0
From Embeds
0
Number of Embeds
3

Actions

Shares
Downloads
0
Comments
6
Likes
28

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Atmosphere Higher Geography Physical Environments
  • 2. Don’t Panic!
  • 3.  
  • 4. Introduction
    • The atmosphere is the layer of gases surrounding the planet Earth and is retained by the Earth's gravitational field.
    • It contains some solid particles including volcanic dust and wind blown soil.
  • 5. Atmosphere Composition
    • Nitrogen – 78.09%
    • Oxygen – 20.95%
    • Argon – 0.93%
    • Plus variable amounts of carbon dioxide and water vapour (greenhouse gases).
  • 6.  
  • 7. 10 100 90 80 120 70 60 50 40 30 20 130 140 110 Height in km -100 -80 -60 -40 -20 0 20 40 Temperature ºC Temperature Change with Altitude Maximum Ozone Temperature Stratosphere Mesosphere Thermosphere Troposphere
  • 8. Variations in Atmospheric Composition
    • The composition of the atmosphere varies with altitude.
    • Industrial areas may also affect the composition of the atmosphere, in particular air quality.
    • Water Vapour (due to evaporation) makes up a significant proportion of the atmosphere close to oceans and seas.
  • 9. Factors which influence climate on a global scale Higher Geography Atmosphere
  • 10. Introduction
    • The Earth receives heat energy (radiation) from the Sun. But not all of the radiation that arrives at the edge of the atmosphere gets to the Earths surface.
    • Also, not all latitudes on the surface receive the same amount of radiation (sunlight).
  • 11. The global heat budget
    • The global heat budget is an atmospheric system which involves inputs, storage and outputs.
    • Generally speaking, incoming solar radiation is balanced by outgoing terrestrial (Earth based) radiation.
    • The balance between incoming and outgoing radiation is known as the global heat budget .
  • 12. Inputs
    • The earth receives all of its incoming radiation from the sun (solar energy).
    100%
  • 13. The global heat budget Atmosphere 23% absorbed by atmosphere 46% absorbed by the surface 17% reflected by clouds 8% reflected by atmospheric gases and dust 6% reflected by surface 100% Solar Energy (short wave)
  • 14. Earths Albedo
    • The earths albedo is the reflectiveness of the surface.
    • In our diagram this was responsible for 31% of the radiation loss.
    • Radiation reflected by clouds ( 17% ) + radiation reflected by atmospheric gases and dust ( 8% ) + radiation reflected by the surface ( 6% )
    • = 31% (total albedo).
  • 15. Outputs
    • Balancing the input is an equal output of heat (terrestrial radiation) from the Earth.
    • 6% of this energy is radiated back into space. The remaining 94% is absorbed by water vapour and carbon dioxide in the atmosphere and re-radiated.
    Carbon dioxide and water vapour are both examples of greenhouse gases
  • 16. The greenhouse effect
    • Eventually all radiation returns to space but the atmosphere’s greenhouse effect slows things down.
    • The greenhouse effect acts like a huge blanket, limiting the heat energy lost.
    Without the greenhouse effect the global temperature would be 33 °C lower.
  • 17. Energy Receipt with Latitude Factors which influence climate on a global scale
  • 18. Insolation
    • Insolation is the suns (solar) radiation which is received by the Earth’s surface.
  • 19. Tropical latitudes receive more solar radiation than the polar latitudes for 3 main reasons. In Polar regions the radiation has to penetrate a greater depth of atmosphere (absorbs more heat). The same amount of solar energy is received over a much greater area in Polar regions (less heating). High energy loss at poles because of ice cap albedo. Equator (0 º) North Pole South Pole
  • 20. Albedo Effect
    • The amount of energy actually absorbed by the surface depends on the Albedo effect . This is the proportion of radiation which is reflected by different surfaces.
    Water – High reflection Forest – Low reflection Ice and snow – High reflection
  • 21. Albedo of various surfaces 5 - 10 Forest 15 - 25 Dry Soil 25 - 30 Grass 20 - 30 Sand (Beach or Desert) 50 - 60 Old Snow 80 - 85 Fresh Snow % Reflected Surface
  • 22.  
  • 23. What does this mean? 90 ºN 60 ºN 30 ºN Equator 0 º 30 ºS 60 ºS 90 ºS 0 100 200 300 Insolation (Joules) Latitude 35 ºN 35 ºS Terrestrial Radiation Insolation There is a net gain (surplus) of energy in Tropical areas because incoming radiation exceeds outgoing radiation. However in polar areas there is a net loss (deficit) of energy because outgoing radiation is greater that incoming radiation.
  • 24. In theory!
    • Theoretically, an imbalance in energy receipt should result in the Tropics becoming hotter and the Poles becoming even colder.
  • 25. 90 ºN 60 ºN 30 ºN Equator 0 º 30 ºS 60 ºS 90 ºS 0 100 200 300 Insolation (Joules) Latitude 35 ºN 35 ºS Energy Surplus Energy Deficit Energy Deficit However, energy is transferred from areas of surplus (Tropics) to areas of deficit (Poles) by atmospheric circulation and by ocean currents.
  • 26.  
  • 27. Understanding Pressure Higher Geography Atmosphere
  • 28. Atmospheric Pressure There are two types of weather systems: These systems affect the weather we receive from day to day. They are caused by differences in atmospheric pressure
    • Low pressure systems
    • High pressure systems
  • 29. What do we mean by air pressure? The earth’s atmosphere is made up of many gases, eg Atmospheric pressure is the weight of these gases pressing down on the surface of the earth. If we could take a column of air covering 1 square centimetre, from sea level to the outer edge of the atmosphere, it would weigh 1 kilogram.
      • oxygen
      • nitrogen
      • carbon dioxide
  • 30. Atmospheric Pressure Outer edge of the atmosphere The Earth’s atmosphere presses down on the surface of the Earth. Atmospheric pressure is measured in millibars ( mb ). The average atmospheric pressure is 1000mb.
  • 31. Changes in Atmospheric Pressure
    • Sometimes atmospheric pressure is higher than average. We call this high pressure .
    • Sometimes atmospheric pressure is lower than average. We call this low pressure .
  • 32. Why does the atmospheric pressure change?
    • If air is heated it rises away from the Earth’s surface.
    • Rising air reduces the weight of air pressing down on the Earth’s surface.
    • This means that air pressure is low .
  • 33. Low Atmospheric Pressure Outer edge of the atmosphere The Earth’s surface is warmed by the sun’s rays. The Earth’s atmosphere presses down on the surface of the Earth. Warm air rises . This reduces the weight of air pressing down on the Earth’s surface. Low Pressure
  • 34. Why does the atmospheric pressure change?
    • When air is cold , high up in the atmosphere it falls towards the earth’s surface.
    • Falling air increases the weight of air pressing down on the Earth’s surface.
    • This means that air pressure is high .
  • 35. High Atmospheric Pressure Outer edge of the atmosphere The Earth’s atmosphere presses down on the surface of the Earth. Cold, dense air falls. This increases the weight of the air pressing down on the Earth’s surface. High Pressure
  • 36. High and Low pressure together Outer edge of the atmosphere The Earth’s surface is warmed by the sun’s rays. Warm air rising causes LOW pressure. Cold air falling causes HIGH pressure. WIND
  • 37. High and Low pressure together Outer edge of the atmosphere The Earth’s surface is warmed by the sun’s rays. Warm air rising causes LOW pressure. Cold air falling causes HIGH pressure. WIND WIND
  • 38. Pressure Systems
    • Low pressure systems are also known as depressions
    • High pressure systems are also known as anticyclones
  • 39.  
  • 40.  
  • 41. Ocean Currents Higher Geography Atmosphere
  • 42. Introduction
    • Oceanic currents play an important role in redistributing energy . They make sure that the low latitudes (equator) does not become too hot and the higher latitudes (Poles) do not become too cold.
  • 43. Oceanic Circulation
    • Energy is redistributed in the oceans by ocean currents, this is called oceanic circulation .
    • This huge movement of water can result in warm water being transferred towards the Poles and cool water being transferred towards the equator.
  • 44. Ocean Currents
    • An ocean current is any more or less permanent or continuous, directed movement of ocean water that flows in one of the Earth's oceans.
    • Ocean currents can flow for thousands of kilometres. They are very important in determining the climates of the continents, especially climate regions next to oceans.
  • 45.  
  • 46.  
  • 47. Gulf stream North Pacific Drift North Atlantic Drift North Equatorial East Greenland West Australian West Wind Drift Brazil Current
  • 48. In simple terms how do ocean currents work? (1)
    • Ocean currents are driven by thermohaline circulation . This is direven from thermo, for heat and haline, for salt, which together determine the density of sea water.
  • 49. In simple terms how do ocean currents work? (2)
    • Uneven heating of surface water in high and low latitudes sets up convection currents which transfer energy.
    • The water round the Poles is more dense than at the equator because it contains more salt. Salt does not freeze.
  • 50. The Thermohaline Conveyor Surface currents (such as the Gulf Stream) head polewards from the equatorial Atlantic Ocean, This dense water then flows downhill into the deep water basins Resurfacing in the northeast Pacific Ocean 1200 years later Deep Cold Water Warm Water Deep Cold Water Shallow Warm Water Shallow
  • 51. Winds
    • Global Winds cause frictional drag on large water surfaces.
    • Ocean currents therefore tend to follow prevailing wind directions .
  • 52. The Coriolis force
    • The Coriolis force means that winds are deflected to the right (clockwise) in the northern hemisphere and to the left (anticlockwise) in the southern hemisphere.
    • Ocean currents are also deflected to the right (clockwise) in the northern hemisphere and to the left (anticlockwise) in the southern hemisphere.
  • 53. Shape of continents
    • Ocean current direction is modified by the shape of the continents .
    • Consequently the major oceanic basins have huge, roughly circular shaped loops of water called gyres .
    A good example of this is the Gyre that forms around the Ivory Coast in Western Africa.
  • 54. Global Climate Change The Physical Core Atmosphere
  • 55. Introduction
    • Over the last few thousand years there have been significant fluctuations in global temperature.
  • 56. Global Climatic Change Time (thousands of years) Average global temperature ( °C) 150 100 125 10 25 50 75 Present 10 15 20 Last Interglaciation Present Interglaciation Last Glaciation
  • 57. Average Global Temperature 0.4 0.2 0 -0.2 -0.4 0.6 -0.6 1860 1880 1900 1920 1940 1960 1980 2000 Temperature Anomaly ( ºC) Year
  • 58. Introduction
    • Fluctuations in global temperature are caused by a variety of physical and human factors which result in an enhanced greenhouse effect .
  • 59.  
  • 60. Greenhouse effect Carbon Dioxide is a greenhouse gas, which means that it allows through energy from the Sun but absorbs heat from the Earth 1. The sun warms the Earth. 2. The Earth reflects some heat away… 3. …but this can’t escape into space. It is trapped by greenhouse gases. THIS MEANS As carbon Dioxide builds up in the atmosphere (30% more than 200 years ago), the Earths air temperature rises. Earths atmosphere
  • 61. Physical factors (1)
    • Changing output of solar radiation:
      • Sunspot activity raise average global temperature.
    • Volcanic eruptions:
      • Dust from volcanic eruptions increase the reflection of solar energy from the sun.
  • 62. Physical factors (2)
    • Over a long period of time oceanic alteration and / or continental drift could have an effect on global temperature.
  • 63. Important
    • Physical causes of global temperature change are nothing new.
    • In recent years human activities are seen as the most important factors in global temperature change.
  • 64. Human Factors (1)
    • Increased consumption of fossil fuels – particularly since the industrial revolution.
    Fossil fuels include coal, gas and oil. When burnt they all produce Carbon Dioxide.
  • 65. Human Factors
    • War – bombing and atomic testing release smoke and dust into the atmosphere this can cause a slight fall in the earth’s temperature, due to increased reflection of solar energy.
    14 kiloton atomic explosion, from a 1951 US nuclear test at the Nevada Test Site.
  • 66. Human Factors
    • Increased methane production from:
      • Rice fields
      • Waste disposal sites
      • Flatulent & belching cattle
  • 67. Human Factors (4)
    • Deforestation – clearance and burning of the tropical rainforest increase the level of CO 2 by reducing the amount recycled during photosynthesis.
    Orbital photograph of human deforestation in progress in the Tierras Bajas project in eastern Bolivia. Photograph courtesy NASA
  • 68. Consequences of Global Warming (1)
    • Air temperature will rise between 1  C and 3.5  C but will not be the same all over the globe.
    eg: Scotland is likely to become warmer but Northern India may actually become cooler.
  • 69. Consequences of Global Warming (2)
    • Precipitation is expected to increase globally but again it will have varied regional impact.
    eg: Scotland is likely to become wetter but the Great Plains, USA, will have less precipitation.
  • 70. Consequences of Global Warming (3)
    • Global sea levels will rise due to:
      • The sea expanding as it warms up
      • The melting of the polar ice caps
    Experts estimate that global temperatures may rise by 2ºC by the year 2100 and that the Mediterranean Sea will rise by 1 metre.
  • 71. Consequences of Global Warming (4)
    • Tropical diseases will spread beyond their traditional locations as warmer areas expand.
    eg: malaria & yellow fever could spread into southern Europe
  • 72.