Ocean Currents Nelson Science 10 Section 13.9 (525) Weather Dynamics Unit Science 10 Mrs. S. Pipke-Painchaud

Weather and Oceans Oceans are very important in creating global weather patterns. 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 What does this mean? What does this mean? –There is a lot of water at the equator to absorb the sun’s rays. What is the purpose of ocean currents? What is the purpose of ocean currents? –Distribute the energy around the world (Nelson Science ) (Nelson Science )

Red = warm currents / Black = cold currents / Orange = water of 20°C or more

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?

Norway and Iceland have harbors that remain ice free all winter. Why?? Norway and Iceland have harbors that remain ice free all winter. Why?? mates/hc_currents_lg.gif

Because of the Gulf Stream, which transports warm water from the Gulf of Mexico 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) 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. Cold currents flow toward the equator and warm as they travel through the region. (Nelson Science ) (Nelson Science )

Causes of Ocean Currents Convection currents Convection currents Wind Wind Earth’s rotation Earth’s rotation Shapes of the continents Shapes of the continents Heat capacity of water Heat capacity of water Amount of salt in water Amount of salt in water

Warm water travels North or South from the equator. Warm water travels North or South from the equator. Cold water is opposite Cold water is opposite Warm water is less dense; Cold water is denser Warm water is less dense; Cold water is denser The sun’s energy is most intense at the equator  starts convection currents 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. (Nelson Science ) (Nelson Science )

Edges of the continents: Edges of the continents: –Currents follow this like a river would Earth rotates eastward 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) What is the only current that travels around the world without running into any continents? What is the only current that travels around the world without running into any continents? –Antarctic Circumpolar (Nelson Science ) (Nelson Science )

Water ~ Heat Sink Remember that water takes a long time to heat up and a long time to cool off. Remember that water takes a long time to heat up and a long time to cool off. Salt Salt –As warm water evaporates it leaves behind saltier currents. –Saltier water is more dense  sinks  deep water currents (Nelson Science ) (Nelson Science )

Effects of Ocean Currents Remember the warmer the air the more moisture it can hold. 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). 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

ma_desert_space.html “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).

Warm currents cause water to evaporate  clouds  large amounts of precipitation Warm currents cause water to evaporate  clouds  large amounts of precipitation –Ex. Brazil Rainforests pictures/brazil_pictu res_1.html

Red shows logging /releases/2005/1021scipak. shtml org/wiki/Category:S outh_America

Ocean Currents and Climate Coastal regions are warmer in the winter and cooler in the summer. 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 Ottawa has a 30 degree difference between winter and summer Newfoundland (further north) has only an 18 degree difference. Newfoundland (further north) has only an 18 degree difference.

High Heat Capacity of Water Our warmest months are June, July and August even though we have more solar energy in May, June and July. Why? 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 Less daylight in November, December and January, but we are colder in December, January and February. Less daylight in November, December and January, but we are colder in December, January and February.

Global Weather Model Please refer to page 536 Please refer to page 536 –Read through the info presented Discuss the following text questions together. Discuss the following text questions together. –Questions on page 527 –1 (b,c,d), 4, 5, 6

Resource Sites: University of Miami University of Miami – Ocean Planet – Smithsonian Ocean Planet – Smithsonian – NET/HTML/oceanography_currents_1.htm l NET/HTML/oceanography_currents_1.htm lhttp://seawifs.gsfc.nasa.gov/OCEAN_PLA NET/HTML/oceanography_currents_1.htm l

Sources Nelson Science 10 Textbook Nelson Science 10 Textbook –Section 13.9 Universe Today – Atacama Desert Universe Today – Atacama Desert – h/printer_atacama_desert_space.html h/printer_atacama_desert_space.htmlhttp:// h/printer_atacama_desert_space.html