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Global Currents

Global Currents. Weather Dynamics Science 10. Previous Knowledge. We already know that uneven warming of the Earth results in different atmospheric temperatures When air warms, it becomes less dense. When air cools, it becomes more dense

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Global Currents

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  1. Global Currents Weather Dynamics Science 10

  2. Previous Knowledge • We already know that uneven warming of the Earth results in different atmospheric temperatures • When air warms, it becomes less dense. • When air cools, it becomes more dense • Fluids move from HIGH to LOW pressure. Therefore, cool air moves towards/under warm air pushing it away

  3. Latitude/ Longitude • Latitude is a measure North or South of the equator • Longitude is a measure east or west from a reference line called the prime meridian.

  4. Warming of the Earth • Temperatures at the equator are much warmer than the Poles. • Because of this, air at equator becomes much warmer. HOW?

  5. Density • The very cold air at the poles will push down towards the equator. • It will slip underneath the warm air and push the air up and away, towards the colder regions

  6. Coriolis Effect • The influence of Earth’s rotation on air, or any object moving on Earth’s surface • We know the atmosphere is moving with the Earth because we can not feel the atmosphere

  7. Prevailing Westerlies • In the central part of the Northern Hemisphere, including most of Canada and the US, the Coriolis Effect causes the winds to blow from WEST to EAST

  8. Eastern Trade Winds • Not all winds blow from west to east. • In certain parts of the globe, the Coriolis Effect results in winds moving from the EAST to the WEST

  9. Jet Streams • Jet Streams are ribbons of extremely fast moving air near the top of the troposphere. • They are caused by the contact of cold and warm air • Found between the ZONES of the globe (polar/temperate, temperate/tropical)

  10. Polar Jet Stream • Affects Canadian weather • Meets at the Polar and Temperate zones • Prevailing westerliesI meet polar easterlies • Cold air will push under the warmer westerlies and cause it to rise • No boundaries (hills, etc) = really fast

  11. Jet Streams • Speeds vary from 100km/hr to 300km/hr • ~ few hundred kilometers wide • Not a perfect circle; continuously meander to the north and south • Areas ABOVE are cold, areas BELOW are warm

  12. Ocean Currents • Follow the same properties of atmospheric currents • Warm water = less dense • Cold Water = more dense • Fresh Water = less dense • Salt Water (salinity) = more dense

  13. Surface/ Deep Ocean • Surface currents run on the top of the ocean and are started by WIND. The shape of the currents is affected by the rotation of the Earth/shape of the continents • Deep ocean currents run at the bottom and are affected by density, temperature, and salinity

  14. Movement • Thermohaline Circulation • The rotation of the planet also affects currents

  15. Coriolis Effect • Waters will be affected in the same way air currents will be • In the Northern Hemisphere, water will move clockwise. In the southern hemisphere, waters will move counter-clockwise

  16. Gyres • These currents are deflected by the continents, causing them to bend and create large current loops called circulation gyres.

  17. Affecting Climate • Colder currents will release less vapour into the atmosphere and will therefore result in a dryer climate • This is where you will find the majority of your deserts. • Ex. Bathroom steaming up.

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