Atmospheric circulation

• Hurricanes are formed by warm ocean currents, high humidity levels, low wind shear, and a pre-existing disturbance such as a tropical wave or a trough.
• A hurricane is an intense tropical cyclone that forms over the Atlantic Ocean
• What are ocean currents?

  Movement of surface water
•  How are ocean currents caused?

  By wind blowing over the surface of the sea
• What do currents set up?

  Circular loops or Gyres
• What does the Coriolis effect cause?

  Currents to go clockwise in the north hemisphere and anti clockwise in th southern hemisphere
• What causes a warm current?

  Current flowing away from the equator (gulf stream)
• What causes a cold current?

  Currents flowing towards the equator (labrador current)
• What is high air pressure?

  -warm air rises

  -low pressure

  -not much air pressing down on the ground
• What is low air pressure?

  -cool air sinks

  -high pressure

  -lots of air pushing on the floor
• What cell is a response to the Polar and Hadley cell?

  Ferrel cell
• What is the Coriolis effect?

  -Global winds blowing from high to low pressure

  -earth constantly rotates and deflects winds to the right in the Northern Hemisphere and the left in the southern hemisphere
• Why is the equator hotter than the poles? (1)

  The earth isnt flat. The sun rays hig the poles at a shallow angle so the heat is spread over a large area. At the equator the suns rayd hit vertically so the same amount of heat is directed at a smaller area.
• Why is the equator hotter than the poles?(2)

  The atmosphere absorbs some of the suns heat. At the poles, the suns rays have more atmosphere to travel through, as it travels through obliquely (diagonally)
• Hot air rises and cold air sinks
• Air always moves from high pressure to low pressure.
• The earth spins. It is wider at the equator than the poles, so the equator spins at a faster speed the arctic circle
• Low pressure is air rising and High pressure is air going down
• ICTZ

  Inter Tropical Convergence Zone