World Circulation movie - water vapor

Winds... attempt to equalize pressure assist movement of ocean currents transfers heat energy Pressure... acts like hills (or "ridges") and valleys ("troughs") redirects air masses and weather patterns Isobars - map pressure

Wind Circulation - horizontal movement of air

1. Pressure gradient - relative closeness of isobar lines
   - closely spaced isobars = steeper gradient
   - steeper gradient = stronger winds
   - flow from high pressure to low pressure always
   
   
2. Coriolis Effect deflects winds flowing down pressure gradients
   - greatest effect at poles, virtually no effect at equator
   - Northern Hemisphere (opposite in S. Hemi) - deflects right
   - Upper atmosphere and equator - pressure gradient and Coriolis Effect are balanced
   - "Geostropic winds" flow parallel to isobars
   
   
3. Friction from landmasses
   - reduces wind speed
   - reduces Coriolis Effect
   - surface winds blow across isobars
   - broken by continents - especially by "friction" near the surface