OCEAN CURRENTSSection 4 – Chapter 13
What is a current?•A current is a large stream of moving water.
•Currents actually MOVE water – waves do NOT move water.
•There are 2 main types of currents:
1)Surface currents2)Deep currents
SURFACE CURRENTS•Affect water several hundred meters deep.
•Driven mainly by the wind.•Most of them flow East or West
Coriolis Effect•The Coriolis Effect is the effect of Earth’s
rotation on the direction of the currents.•Northern Hemisphere – currents flow to
the right; clockwise•Southern Hemisphere – currents flow to
the left; counterclockwise
Click the Earthfor video explanation!
The GULF STREAM•The largest, most powerful surface
current in the Atlantic Ocean.•It carries warm water from Mexico to
Carribean then northward along coast of US – at NC it curves outward due to Coriolis Effect!
Gulf Stream
Surface Currents Affect Climate•Warm/Cold water currents will warm or
cool the air above them and influence the climate on land.
•Air over warm currents tend to pick up moisture and bring rain to land.
•Cold currents will cool the air which can’t pick up as much moisture which results in cooler, drier weather.
El Nino•Unusual wind patterns will change the
currents flow in the Pacific Ocean. • It happens every 2-7 years.•This change causes weather patterns to
shift towards more severe weather occurances like extra rainy(flooding/mudslides), mild winters, incident of tornadoes increases, etc.
Ocean Temp Comparison
El N
ino
– Tem
ps
are
high
er
Wind Patterns Shift
DEEP CURRENTS•Caused by differences in density of ocean
water due to difference in temperature/salinity.
•Flow more slowly than surface currents – one circuit around can take up to 1000 years!
•Cold water flows from the poles towards the equator.
•Sometimes called “thermohaline” currents or the “conveyor belt”
UPWELLING•Movement of cold, deep water upwards
towards the surface.•Important b/c it brings nutrients from the
ocean floor up towards the surface.•Fish & other organisms depend on this
upwelling for their survival.•Many upwelling regions contain hundreds
of schools of fish.