1. PLANETARY
WIND SYSTEM

2. Coriolis Effect

3. Coriolis occurs because the Earth rotates.
Earth rotates about its axis every 24 hours.
Distance around the equator is 25,000 miles
the earth is travelling east at 1,000 miles per hour.
Distance around the Earth at 40ºN 19,000 miles
the earth is travelling east at 800mph.
The Coriolis effect results from this difference in velocity.
In the Northern hemisphere the Coriolis effect
deflects movement to the right.
In the Southern hemisphere Coriolis effect
deflects movement to the left.
The combination of atmospheric cells
and Coriolis effect lead to the wind belts.
Wind belts drive surface ocean circulation

4. Planetary Winds Winds are named by the direction they blow from.
High Pressure
Coriolis effect
WIND
pressure gradient force
Low Pressure
Winds are named by the direction they blow from.

5. Wind Belts 90ºN 60ºN Temperate Low LP 30ºN
Polar easterlies
60ºN
Temperate Low LP
South westerlies
30ºN
Sub-tropical High - Horse Latitudes HP
NE Trades 0º
Equatorial Low - Doldrums LP
SE Trades
30ºS
Sub-tropical High - Horse Latitudes HP
North westerlies
60ºS
Temperate Low LP
Polar easterlies
90ºS

6. Wind Belts 60ºN 30ºN 0º 30ºS 60ºS 90ºS Polar easterlies convergence LP
South westerlies
30ºN
divergence Sub-tropical High HP
NE Trades 0º
convergence Inter-tropical convergence zone LP
SE Trades
30ºS
divergence Sub-tropical High HP
North westerlies
60ºS
convergence LP
Polar easterlies
90ºS

7. Wind Belts

8. Wind Belts Northern Hemisphere
Polar Easterlies Blowing from the Polar High Pressure zone to about 60ºN
Westerlies Blowing from Sub-Tropical High Pressure zone to about 60ºN
Northeast Trade Winds Blowing from Sub-Tropical High Pressure zone to Equatorial Low Pressure zone.
Southern Hemisphere
Southeast Trade Winds Blowing from Sub-Tropical High Pressure zone to Equatorial Low Pressure zone.
Westerlies Blowing from Sub-Tropical High Pressure zone to about 60ºS
Polar Easterlies Blowing from the Polar High Pressure zone to about 60ºS
Wind Belts

9. PRESSURE AND WIND PATTERNS
SUMMARY:
There are basically three main wind belts in each hemisphere
Trade Winds
Westerlies
Easterlies
Trade winds lie between 30degrees N and S of the Equator
Caused by movement from High-pressure at the tropics towards low pressure at the equator
They are deflected by the Coriolis Effect
TO THE RIGHT IN THE NORTHERN HEMISPHERE
TO THE LEFT IN THE SOUTHERN HEMISPHERE
Westerlies flow polewards from the high-pressure tropical areas towards the mid-latitudes
Again they are deflected
Easterlies - Small belts of wind flow out from the poles from the east then to the west in both hemispheres
Only in winter in the Northern hemisphere

10. OCEAN
CURRENTS

11. OCEAN CURRENTS PATTERN OF OCEAN CURRENTS EXPLANATION OF OCEAN CURRENTS
DVD – Power
Of the Planet
(Oceans)