Transcript 25. Weather Part 7 – The Coriolis Effect on Winds and Currents

The Coriolis Effect on
Winds and Currents
Consider This:
 The Coriolis force has been observed since at least
the 1650’s.
 Italian military officers wrote that in artillery
practice the cannon balls always landed to the right
of where they aimed and predicted.
Earth’s Rotation
 The Earth is a sphere and rotates on an axis.
 Counter-clockwise when looking down from the north
pole.
 The equator must rotate
fastest to “keep up”.
The Coriolis Effect
 Causes moving objects to:
 Turn to the right in the northern hemisphere.
 Turn to the left in the southern hemisphere.

These are from the direction you are looking.
 The Coriolis Effect from MIT
 The Coriolis effect has a huge influence on weather
patterns!
Remember:
 The shape of the Earth causes different locations to
have different temperatures.
 Warm air rises because it is less dense.
 Objects in the air are deflected because of the
Coriolis Effect.
Air Circulation
 There are three convection currents in each
hemisphere.
 Called cells.
Global Winds
 The air moving north or south because of
convection, still moves east or west because of
rotation.
 The cells are deflected because of the Coriolis
Effect.
 Global Atmospheric Circulation
Global Winds
 Wind systems are wide zones of prevailing winds.
 Trade Winds
 Prevailing Westerlies
 Polar Easterlies
 Occur in both hemispheres.
Jet Stream
 A narrow band of strong, fast-moving winds.
 In upper-level air.
Jet Stream
 Caused by uneven temperatures and the Coriolis
Effect.
 Jet streams generate large scale weather systems.
 What is a Jet Stream?
Think About It:
 The atmosphere and the ocean act as one system
called the air-sea interface.
 How do the winds impact the ocean?
 How does Earth’s rotation impact the ocean?
Ocean Currents
 Ocean currents travel in the direction of the wind
and are impacted by the Coriolis Effect.
 Gyres:
 Circular ocean currents.
Ocean Currents
 Warm currents from the equator towards the poles.
 Cold currents from the poles towards the equator.
 Left side is always warm.
 Right side is always cold.
Think About It:
 Circulating air has a big impact on our weather.
 Ocean currents also have a big impact on our
weather.
 Both impacted by the Coriolis Effect.