the global ocean the vast world ocean
DESCRIPTION
Objectives What is oceanography? What is the extent and distribution of the world’s oceans? What techniques are used to map the ocean floor?TRANSCRIPT
![Page 1: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/1.jpg)
The Global OceanThe Vast World Ocean
![Page 2: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/2.jpg)
Objectives
• What is oceanography?• What is the extent and distribution of the
world’s oceans?• What techniques are used to map the
ocean floor?
![Page 3: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/3.jpg)
What is oceanography?
• Interdisciplinary science• Draws on methods/knowledge of geology,
chemistry, physics, biology
![Page 4: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/4.jpg)
Ocean Geography
• Earth’s surface area: ~510 million km2
• Oceans + marginal seas (Mediterranean, Caribbean, etc.): ~360 million km2 (71%)– Northern hemisphere: 61% water, 39% land– Southern hemisphere: 81% water, 19% land
![Page 5: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/5.jpg)
Distribution of Land & Water
![Page 6: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/6.jpg)
Uneven Land & Water Distribution
![Page 7: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/7.jpg)
Four Ocean Basins +• Pacific
– > half of total ocean surface area – all continents could “fit” in it
– Deepest (3940 meters)• Atlantic
– Half the size of the Pacific– Average depth is 3339 meters– Land that drains into the Atlantic covers four
times that of either the Pacific or Indian oceans
![Page 8: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/8.jpg)
Four Ocean Basins +• Indian
– About the same average depth as Atlantic but slightly smaller
– Mostly in Southern Hemisphere• Arctic
– Surface area is ~ 7% of Pacific Ocean– 25% as deep
![Page 9: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/9.jpg)
Four Ocean Basins +• Southern Ocean
– Meeting of currents near Antarctica– Portions of Pacific, Atlantic & Indian south of
50 latitude
![Page 10: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/10.jpg)
Four Ocean Basins +
![Page 11: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/11.jpg)
Four Ocean Basins +
![Page 12: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/12.jpg)
Comparing the Oceans to the Continents
• Continents – 840 meters above S.L. (average)
• Oceans – 3729 meters deep
![Page 13: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/13.jpg)
The Global OceanAn Emerging Picture of the Ocean Floor
![Page 14: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/14.jpg)
Mapping the Seafloor
• HMS Challenger (1872-1876)– 1st comprehensive study of global ocean– Measured water depth using weighted lines
![Page 15: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/15.jpg)
Mapping the Seafloor
![Page 16: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/16.jpg)
Mapping the Seafloor
![Page 17: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/17.jpg)
Modern Bathymetric Techniques
• Bathymetry – measurement of ocean depths and the charting of the topography of the ocean floor
• SONAR – sound navigation and ranging
![Page 18: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/18.jpg)
Modern Bathymetric Techniques• Echo sounders
– Early 20th century– Transmit sound wave
(ping) that echoes when it hits an object
– Travel time is measured – Depth =
1 meters1500 echo travel time in seconds2 sec
![Page 19: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/19.jpg)
Mapping the Seafloor
Scientists "See" Ocean Floor via Sonar
Side Scan SONAR
![Page 20: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/20.jpg)
Viewing the Ocean Floor From Space
• Radar altimeter measures ocean surface height variations induced by ocean floor topography.
• Better resolution but much higher cost if an echo sounder is used.
• When interesting features are discovered in satellite gravity measurements, these can be surveyed in fine detail by ships.
![Page 21: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/21.jpg)
![Page 22: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/22.jpg)
![Page 23: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/23.jpg)
Seismic Reflection Profiles• Strong low-frequency sounds are
produced by depth charges.• Used to estimate the properties of the
Earth's subsurface from reflected seismic waves.
![Page 24: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/24.jpg)
Provinces of the Ocean Floor
• Continental margins• Deep-ocean basins• Oceanic (mid-ocean) ridge
![Page 25: The Global Ocean The Vast World Ocean](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1acf7f8b9ab059970c64/html5/thumbnails/25.jpg)
Provinces of the Ocean Floor