CURRENTS

III. CURRENTS- move large amounts of water

• A. Deep Water Currents (density driven)

• why does the density of water change? cooling , evaporation, and freezing

B. SURFACE- (wind driven)

• sun is responsible for uneven heating of the atmosphere and water.

• Circulation of oceans fig. 1-17 and 1-18. Cooler water is more dense and therefore sink

•

B. Coriolis effect-surface deflection • Gaspar de Coriolis

1835 Observed phenomenon " an apparent "force" on moving particles resulted from the earth's rotation"

• "apparent deflection of any moving object not attached to the earth's surface"

• Rotation of the earth pulls and deflects the wind and water to the...

• right in the north 45 degrees• left in the south• amount of deflection depends on velocity

and latitude

• Generates large rivers of water "gyres" not centered in the oceans

C. Ekman spiral• a theoretical

representation of the effect of the wind blowing steadily over the ocean.

• deep water deflection down 100 to 200 m (328 to 656 ft.)

• caused by the "drag" of successively deeper layers of water.

• ***** in the water off the coast of FLA., winds blowing from the south along the Atl. coast drive surface waters to the right or off shore. Coastal water is replaced by cooler- nutrient rich waters from depths of 200-300 m. Myrtle beach can get very cold ******

D. Upwellings

• Oxygen carried down for respiration

• Organic carries material up for fertilization of algae

• *** Peruvian Coast- warm water pushed offshore by southern winds, allows space for cold water upwelling. El Nino: when the warm water remains close to the shore. Destroys the anchovy fishing. El Nino because it is near Christmas.******