Mrs. Kummer Fall, 2014

What types of Ocean Currents Exist? Two Types of Ocean Currents: Surface Currents Deep Currents Surface Currents: Move on or near the surface of ocean water, driven by winds Deep Currents: Move VERY SLOWLY beneath the surface of oceans, driven by changing densities

What Factors Impact Surface Currents? Three Factors: 1. Wind Belts, 2. Earth’s Rotational Effects, and 3. Location of Continents 1. Wind Belts: Trade winds: Located just north and south of equator Westerlies: Located in middle latitudes

What Factors Impact Surface Currents? Three Factors: Wind Belts, Earth’s Rotational Effects, and Location of Continents 2. Earth’s Rotational Effects Coriolis Effect: Deflection of the earth’s winds and ocean currents caused by Earth’s rotation Gyres: huge circles of moving water formed by Coriolis Effect Northern Hemisphere: Flow of water is CW Southern Hemisphere: Flow of water is CCW

What Factors Impact Surface Currents? Three Factors: Wind Belts, Earth’s Rotational Effects, and Location of Continents 3. Location of Continents Currents near a landmass (island, continent, etc.) bounce off landmass and divide/deflect the flow of water Can trap the same water for long periods of time in sea areas (Gulf of Mexico, Boston Harbor, etc.)

Surface Currents in the Ocean There are four main areas of surface currents: 1. Equatorial Currents  Found at equator of Atlantic, Pacific, and Indian Oceans  Currents move Westward 2. Currents in North Atlantic and Pacific  Gulf Stream: warm, fast moving current from Caribbean up to North Atlantic  Meets cold Labrador Current near Baffin Bay in North Atlantic  This cold meeting warmer causes lots of fog in UK 3. Currents in Southern Hemisphere 4. Currents in Indian Ocean

Surface Currents in the Ocean There are four main areas of surface currents: 3. Currents in Southern Hemisphere  West Wind Drift: World’s Largest current at the bottom of the globe where no landmasses stop it  Slower moving, continuously travels around Antarctica 4. Currents in Indian Ocean  Ocean currents driven by monsoons  Monsoons are winds that change direction each season

Global conveyor belt

Directions of Ocean Currents The direction is influenced by many different factors.

DIRECTIONS OF OCEAN CURRENTS

Deep Currents Three Types of Deep Currents 1. Turbidity Currents: strong current caused by an underwater landslide 2. Antarctic Bottom Water  Located near bottom of Southern Ocean  Temp= -2°C, Salinity=3.5%, so densest water in the world  Very very slowly moves northward  Goes 1000’s of km’s, taking several hundreds of years to make the trip! 3. North Atlantic Deep Water  Just south of Greenland, cold high salinity water  Moves southward below the Gulf Stream

Map of Deep Currents

Waves-How Big Are They? Swells: Group of long, rolling waves traveling together Wave Size Determined by Three Factors:  Fetch: The distance the wind can blow across open ocean  Windspeed  Length of time the wind blows  Whitecaps: the top of the wave is blown off by the wind, leaving a white foamy top at sea  Breakers: whitecaps that break the top off right at the shoreline, leaving a white foamy top

Biggest Waves: Tsunamis Not powered by wind, it is a seismic wave powered by earthquakes Very very long wavelength Out at sea, the tsunami is 240km wavelength, 15min long wave period, and speed of 450 mph As it approaches shore, its height increases, speed decreases When the trough (bottom) arrives before the crest (top), the water at the shoreline is pulled back Then massive amounts of waves arrive on the shore every 15min (or wave period length of time)

How Tsunamis Work

Wave parts Speed = wavelength/Period

What are Tides? Daily changes in level of ocean surface Discovered in 1600’s by Newton Caused by rotation of Moon and Earth together (like 2 ice skaters holding hands and spinning together) 2 high tides and 2 low tides daily