Monsoonal Circulation: Winter and Summer
- winter: cool, dry, North to South
- summer: wet, humid, South to North
Surface winds: Direction near equator
-East to West
Surface winds: Direction in Mid-lattitude
-West to East
Surface winds: Direction in High-latitude
-East to West
Surface currents help with..
pole ward heat transfer
Main force for Surface Currents
frictional drag
Oceans currents don’t move same as wind because..
combination of friction force and Coriolis force
5 Subtropical Gyres creates by…
wind, gravity, Coriolis force and continents
Ekman Trasnfer
- rotating column of water
- forms when water moves at an angle to wind direction (due to Coriolis force)
- movement at right angle to wind direction (NH)
Equatorial Upwelling
- trade winds blow away warm surface water
- cool water below upwells and takes place
Coastal Upwelling
-southward surface winds along coast bring up cold water
Tidal Movement
- horizontally, creates currents
- gravity of moon pulls water
Full Moon/New Phase on Tides:
strongest current
-“spring currents”
First Quarter/Third Quarter Moon on Tides
- weakest currents
- “neap currents”
Perigean Currents
- Earth and Moon closest together
- strong currents
Apogean Currents
- Earth and Moon furthest together
- weakest currents
Thermohaline Currents
- salt in seawater put back upon freezing
- increases density of ocean
- cools, and drives downwelling (SINKS)
Gulf Stream, North Atlantic Drift
- warm water flows north (evaporates and cools)
- then sinks in Labrador and Greenland Seas
Upwelling Cycle
~ 1 000 years at least
Thermohaline Current: Full process
- starts at surface in North Atlantic
- surface water replaces downwelling water
- travels south down to Antarctica where is cool and sinks again
- splits, one North to Indian ocean one to west Pacific
- two branches warm and rise, the loop heads south west
- warmed and continues to circulate until it reaches the North Atlantic once again
