PLANETARY WIND SYSTEM

Coriolis Effect

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

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.

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

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

Wind Belts

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

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

OCEAN CURRENTS

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