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El Nino

El Nino a global threat is one of the most serious issues and threats to many countries across the world

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El Nino

  1. 4. <ul><li>Sunspots </li></ul><ul><li>2. Arrangements of continents </li></ul><ul><li>3. Natural catastrophes – meteorites and volcanoes </li></ul><ul><li>4. Earth’s orbit (Milankovitch cycles) – </li></ul><ul><li>a) Eccentricity – shape of orbit changes every 100,000 years </li></ul><ul><li>b) Tilt – oscillates by 1.5 ° every 41,000 years </li></ul><ul><li>c) Wobble – circles the axis every 23,000 years. </li></ul><ul><li>5. Changes in ocean currents </li></ul>
  2. 5. <ul><li>El Niño is an oscillation of the ocean-atmosphere system in the tropical Pacific having important consequences for weather around the globe. </li></ul><ul><li>During El Ni ño winds across the Pacific change direction and blow from West to East. </li></ul><ul><li>This changes the weather patterns around the Pacific. </li></ul><ul><li>Occurs every 3 – 7 years although they appear to be getting more regular </li></ul>
  3. 6. El Nino happens in this area of the world in the Pacific Ocean
  4. 7. <ul><li>The trade winds move warm surface water towards the western Pacific </li></ul><ul><li>Cold water wells up along the west coast of South America (near Peru) </li></ul><ul><li>Upwelling important for fish stocks in Peru </li></ul>
  5. 8. <ul><li>Air pressure over West coast of S. America becomes low and air over west Australia high pressure </li></ul><ul><li>The normal east to west trade winds over pacific are disrupted and warm water ‘sloshes’ eastwards </li></ul><ul><li>No upwelling on South American coast </li></ul>
  6. 9. <ul><li>There are a few theories that surround it’s cause and here are a few. </li></ul><ul><li>Rossby wave - wave lowers Thermocline in W. Pacific reducing the upwelling of water. Winds then blow towards warmer water and event starts. </li></ul>
  7. 10. <ul><li>Tropical storms </li></ul><ul><li>if storms are strong enough they can blow water eastwards and start the event. </li></ul><ul><li>Heat from sea floor </li></ul><ul><li>by sea floor volcanoes (no evidence) </li></ul>
  8. 11. <ul><li>El Nino the Movie </li></ul>
  9. 12. <ul><li>With the movement of warm water back Eastwards it prevents any upwelling of cold nutrient-rich, water on which Plankton feed. Plankton is the main food of the anchovy which is one of the main fishing types in Peru! </li></ul>Warm water also expands. So as the water piles back East towards Peru sea levels increase by 30cm! ( Thermocline – sharp boundary between cold deep water and warmer surface water.)
  10. 13. <ul><li>This means the knock on effects around the world </li></ul>Reduced Hurricane Activity Hot Summers in Europe Floods in Kenya and Bangladesh Droughts in Brazil Fires in Indonesia
  11. 14. <ul><li>A third weather condition can arise called La-Nina </li></ul><ul><li>Really simple! All it is, is an exaggerated version of normal conditions. </li></ul>
  12. 15. <ul><li>Air pressure is unusually high over the west coast of South America and low over Eastern Australia </li></ul><ul><li>As warm water is pushed westwards sea levels rise by up to 1m </li></ul><ul><li>Around Indonesia and Philippines. Strong uplift of air leads to heavy Rain! </li></ul><ul><li>Global climate La Niña impacts tend to be opposite those of El Niño impacts </li></ul>
  13. 16. <ul><li>El Nino years are characterised by an increase in the amount of natural disasters </li></ul><ul><li>They upset the balance around the globe causing distinct changes in climate </li></ul><ul><li>We are still unsure what affects climate change will have on these processes </li></ul>

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