Oceanography Slides November 2007

EQUATOR 1.Warm water moves along surface away from equator Density Currents 

EQUATOR 1.Warm water moves along surface away from equator 2.As water cools it becomes more dense and sinks to the seafloor Density Currents  

EQUATOR 1.Warm water moves along surface away from equator 2.As water cools it becomes more dense and sinks to the seafloor 3.Cold water moves along seafloor back towards equator Density Currents   

EQUATOR 1.Warm water moves along surface away from equator 2.As water cools it becomes more dense and sinks to the seafloor 3.Cold water moves along seafloor back towards equator 4.Cold water currents meet near equator and rise to surface, form UPWELLINGS Density Currents    

EQUATOR 1.Warm water moves along surface away from equator 2.As water cools it becomes more dense and sinks to the seafloor 3.Cold water moves along seafloor back towards equator 4. Cold water currents meet near equator and rise to surface, form UPWELLINGS -will also occur along edges of continents if currents are deflected up the continental slope -are areas of very good fishing Density Currents    

This is because there is a constant flow and mixing of waters between all of the oceans.

Upwelling Vertical density current Vertical density current Most common on WEST side of continents Most common on WEST side of continents Prevailing winds blow along coastline toward equator (+Coriolis Efect) Prevailing winds blow along coastline toward equator (+Coriolis Efect)  winds push coastal surface water away from coast  winds push coastal surface water away from coast  cold, nutrient-rich water rises up  cold, nutrient-rich water rises up Example: Peru and anchovies Example: Peru and anchovies

Wave Focus: TIDES Bulge of water on side closest to Moon (centripetal force) Bulge of water on side closest to Moon (centripetal force) Bulge of water on side farthest away from Moon Bulge of water on side farthest away from Moon (centrifugal force or (centrifugal force or pony tail force- DEMO) pony tail force- DEMO) Earth rotates underneath the bulge

Wave Focus: TIDES Cause: Gravitational Attraction * Distance is a larger control than Mass  Moon is more important for tide creation on Earth  Relative positions of Moon, Sun & Earth increase or decrease gravitational attraction & tides All aligned = SPRING tide (highest high tide, largest tidal range) Sun & Moon at right angle to Earth = NEAP tide (lowest high tide, smallest tidal range)

Wave Focus: TIDES Factors that Influence the Expression of Tides: Size of basin Size of basin Coastline shape Coastline shape Position of Earth in its orbit around Sun Position of Earth in its orbit around Sun Distance between them changes Distance between them changes Position of Moon in its orbit around Earth Position of Moon in its orbit around Earth Distance changes Distance changes Steepness of land along coast Steepness of land along coast Any others??? Any others???