Download Ocean Currents

Ocean
Currents
Nelson Science 10 Section 13.9 (525)
Weather Dynamics Unit
Science 10
Mrs. S. Pipke-Painchaud
Weather and Oceans
n
Oceans are very important in creating global
weather patterns.
– Occupy a large portion of the earth’s surface
– Most land masses are found at 45* north
n
What does this mean?
– There is a lot of water at the equator to absorb the sun’s
rays.
n
What is the purpose of ocean currents?
– Distribute the energy around the world
n (Nelson Science 10 525)
http://www.oceansonline.com/ocean_currents.htm
Red = warm currents / Black = cold currents / Orange = water of 20°C or more
http://www.starfish.ch/reef/ocean.html
http://www.studyofplace.com/ActivityContent/M2_A3_S02b.html
Ocean Currents
(top)
Wind Patterns
(Bottom)
~ Do you notice
any similarities or
differences?
Iceland and
Norway are
located at
what latitude?
What climate would
you expect them to
have based on their
similarity to the same
Canadian latitude?
n
Norway and Iceland have harbors that remain ice
free all winter. Why??
http://www.bigelow.org/ship
mates/hc_currents_lg.gif
n
n
n
Because of the Gulf Stream, which
transports warm water from the Gulf of
Mexico
Ocean currents transport energy stored in
the water from one part of the world to
other parts (warm to cold)
Cold currents flow toward the equator and
warm as they travel through the region.
n
(Nelson Science 10 525)
Causes of Ocean Currents
n
n
n
n
n
n
Convection currents
Wind
Earth’s rotation
Shapes of the continents
Heat capacity of water
Amount of salt in water
n
n
n
n
Warm water travels North or South from the
equator.
Cold water is opposite
Warm water is less dense; Cold water is
denser
The sun’s energy is most intense at the
equator  starts convection currents
– Water warmed by the sun’s rays at the surface
moves north or south, the cold water from the
bottom moves up to the surface.
n
(Nelson Science 10 526)
n
Edges of the continents:
– Currents follow this like a river would
n
Earth rotates eastward
– Currents on the West side of the oceans  narrow and
faster (6.5 km/h)
– Currents on the East side  wider and slower (1.1 km/h)
n
What is the only current that travels around the
world without running into any continents?
– Antarctic Circumpolar
n
(Nelson Science 10 526)
Water ~ Heat Sink
n
n
Remember that water takes a long
time to heat up and a long time to
cool off.
Salt
– As warm water evaporates it leaves
behind saltier currents.
– Saltier water is more dense  sinks 
deep water currents
n
(Nelson Science 10 526)
Effects of Ocean Currents
n
n
Remember the warmer the air the
more moisture it can hold.
If a cold ocean current runs by a
coastal areas, then the air is cooler
and drier (may cause a desert).
– Peru current is cold = cold, dry air =
Atacama Desert
http://digilander.libero.it/luigipizzi/Atacama.jpg
“Bounded on the west by
the Pacific and on the east
by the Andes, the Atacama
Desert only knows rainfall
between two and four
times a century. . . There
are some parts of the
desert where rainfall has
never been recorded. The
only moisture available
comes from a dense fog
known as camanchaca,
formed when cold air
associated with ocean
currents originating in the
Antarctic hits warmer air.
This fog is literally
harvested by plants and
animals alike, including
Atacama's human
inhabitants who use 'fog
nets' to capture it for
drinking water”
(Universe Today).
http://www.universetoday.com/am/publish/printer_ataca
n
Warm currents cause water to evaporate 
clouds  large amounts of precipitation
– Ex. Brazil Rainforests
http://www.bugbog
.com/gallery/brazil_
pictures/brazil_pictu
res_1.html
Red shows logging
http://www.aaas.org/news
/releases/2005/1021scipak.
shtml
http://en.wikinews.
org/wiki/Category:S
outh_America
Ocean Currents and
Climate
n
Coastal regions are warmer in the
winter and cooler in the summer.
– i.e. Ottawa vs Newfoundland
Ottawa has a 30 degree difference between
winter and summer
n Newfoundland (further north) has only an 18
degree difference.
n
High Heat Capacity of
Water
n
Our warmest months are June, July
and August even though we have
more solar energy in May, June and
July. Why?
– Water takes a while to warm up
– Same effect in the winter
n
Less daylight in November, December and
January, but we are colder in December,
January and February.
Global Weather Model
n
Please refer to page 536
– Read through the info presented
n
Discuss the following text questions
together.
– Questions on page 527
– 1 (b,c,d), 4, 5, 6
Resource Sites:
n
University of Miami
– http://oceancurrents.rsmas.miami.edu/
n
Ocean Planet – Smithsonian
– http://seawifs.gsfc.nasa.gov/OCEAN_PLA
NET/HTML/oceanography_currents_1.htm
l
Sources
n
Nelson Science 10 Textbook
– Section 13.9
n
Universe Today – Atacama Desert
– http://www.universetoday.com/am/publis
h/printer_atacama_desert_space.html