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Chapter 15 Physical Oceanography.

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Presentation on theme: "Chapter 15 Physical Oceanography."— Presentation transcript:

1 Chapter 15 Physical Oceanography

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12 71 percent of the planet is covered by Oceans

13 Average depth 3800 meters (2.4 miles)

14 Sea level is dependent on the amount of water
stored as ice on the planet.

15 Sea level is rising 1 - 2 mm a year on average.

16 The Ocean Pacific Atlantic Indian
Seas are bodies of water completely (or almost completely) surrounded by land. Divide the class up into groups give them an atlas or globe. Are the oceans all connected? Which is the largest named ocean? Which oceans border the U.S.?

17 *** Ocean Geography Are all the major oceans and seas connected?
Name the three major oceans. Which hemisphere (north or south) of the Earth has the greatest percentage of water? Which major ocean is the largest? Which oceans, gulfs, & seas border North America? What bodies of water border the country of Japan? Name the seven continents

18 Sea Ice Forms in the Arctic and Antarctic oceans.

19 Pancake Ice forms from slushy frozen ice crystals
brought together by wave action. It thickens to form more rounded sheets (pancakes).

20 Currents bring the ice together and compress it.
It becomes pack ice.

21 The pack ice will become solid in the winter months
carried by currents in the ocean waters.

22 Pack ice freezes solid in many areas in the winter months.
In summer the pack ice breaks up and some of it melts. Pack ice freezes solid in many areas in the winter months. In recent years the extent of the ice has been getting smaller.

23 Physical properties of seawater
Seawater is 96.5% water and 3.5% dissolved salts. Sodium chloride Magnesium chloride Potassium chloride Calcium chloride Other substances Average 35 ppt Refer to p 393 Salinity map Note differences in added freshwater make a difference (glacial melting, areas of high precipitation) brackish How do the ions get into the ocean? Ans: rivers and streams

24 Physical properties of seawater.
Where does the salt come from? Chemical weathering of rocks. Refer to figure 15-13 What are some other ways chemicals can get in the ocean? Dumping, water pollution, air pollution, volcanic action. Both man and non man made sources. Ions are carried to the ocean by rivers and streams.

25 Physical properties of seawater.
Salinity stays the same. Precipitation in arid coastal areas Refer to figure 15-13 Salt spray from breaking waves. Marine organisms remove salts to build their shells, bones, and teeth.

26 Physical properties of seawater.
Sea water freezes at -2o C. Fresh water freezes at 0o C. Sea water is more dense because salt molecules are heavier than water molecules. (refer to periodic table) Differences in density affect ocean circulation which affects all life on Earth. Sea water has a higher density than fresh water. Cold water has a higher density than warm water.

27 Light only penetrates 200 meters into the ocean
(100 meters on average). Refer to figure in text Review prism and how light consists of ROYGBIV Photosynthesis is the process whereby plants produce nutrients in the presence of sunlight. Review what photosynthesis is 100 meter depth varies based on what??? Clarity of the water. Enough light for Photosynthesis is only available in the top 100 meters.

28 Below 100 meters the ocean is dark.
Only the surface water is warm. Deep water is always very cold (below 4oC). A thermocline seperates warm surface water from deep cold water. The thermocline is thicker at the equator. The thermocline and warm surface water do not exist at the poles. Refer to figure 15-15

29 Below 100 meters the ocean is dark.
Cold water migrates toward the equator at the surface and bottom of the ocean. Warm water migrates toward the poles near the surface. 95% of the ocean has not been explored. Many interesting creatures live in the dark depths of the ocean Like these scary creatures…………….. Refer to figure 15-15

30 Water Density Fresh water at 28o C Fresh water at 2o C

31 Water Density Salt water at 20o C Fresh water at 20o C

32 *** Water Density Fresh water at 28o C Salt water at 28o C

33 Ocean currents Surface currents Deep water density currents Gyres
Upwelling Refer to figure 15.5 p 389 Refer to figure p 404 Explain global currents without continents Explain global energy flow through ocean currents

34 *** Ocean Currents

35 Compare and contrast the California current and the Gulf Stream in terms of temperature and direction (use map on p.404). Which direction(clockwise / counterclockwise) do currents generally flow in the northern hemisphere? , and southern hemisphere? The wind creates surface currents -what force makes these currents rotate they way they do? Explain how this force effects the ocean currents. Compare the water temperature in the northward vs. southward flow in the North Atlantic Gyre? What form of energy is transferred in the warm currents that flow from the equatorial regions to the polar regions?

36 *** Computer - Ocean Currents
Copy the assignment from the Fuglestad drop box *** Go the website and watch Water, Water Everywhere Follow the directions Turn in your completed assignment to the Fuglestad drop box

37 A wave is a rhythmic movement that carries
Refer to Figure A and B A wave is a rhythmic movement that carries energy through space or matter.

38 Anatomy of a wave The wave length is the distance between successive crests of a wave. The wave height is the distance from the trough to the crest of a wave.

39 Crest Crest Trough Breaking wave

40 Anatomy of a wave

41 Deep water waves - wave height
Normal wave height in the open ocean is between 0.3 and 5 meters (1 to 15 ft.) Wave height depends on: Wind speed Wind duration Fetch Hurricanes produce waves as high as 130 feet. Tsunami waves have extremely long wavelengths. Tsunami waves can be 300 feet high at the shcre. Fetch is the size of the body of water that the wind blows across

42 Deep water waves - wavelength
Normal wavelength is between 40 and 400 meters. (130 to 1300 ft.) The greater the wavelength the greater the speed of the wave. Speeds vary from 15 to 55 miles an hour. These waves are created by the wind. Tsunami waves have extremely long wavelengths. Tsunami waves can be 300 feet high at the shcre.

43 Characteristics of waves in shallow water
Waves encounter friction with the bottom at wave base. Wave height increases as the wave continues to drag on the bottom. Wavelength simultaneously shortens. Wave become higher and steeper until they collapse “wave breaks” The energy in the wave is primarily used up moving sand along the beach.

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