Podcast
Questions and Answers
Oceans cover 67 percent of the Earth's surface and receive around two thirds of the Sun's energy.
Oceans cover 67 percent of the Earth's surface and receive around two thirds of the Sun's energy.
True
Ocean currents are movements of water that only flow vertically.
Ocean currents are movements of water that only flow vertically.
False
Warm currents transport colder water from higher latitudes to lower latitudes.
Warm currents transport colder water from higher latitudes to lower latitudes.
False
Ocean currents transfer about 25 percent of the global heat budget.
Ocean currents transfer about 25 percent of the global heat budget.
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Both temperature and salinity affect the density of water, with colder and saltier water being less dense.
Both temperature and salinity affect the density of water, with colder and saltier water being less dense.
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The Coriolis effect causes surface waters to be diverted to the left in the northern hemisphere.
The Coriolis effect causes surface waters to be diverted to the left in the northern hemisphere.
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Cold, salty surface water sinks near Antarctica because it is very dense.
Cold, salty surface water sinks near Antarctica because it is very dense.
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Ocean currents predominantly flow directly towards regions of high density.
Ocean currents predominantly flow directly towards regions of high density.
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The main subtropical gyres in the Northern Hemisphere flow anti-clockwise.
The main subtropical gyres in the Northern Hemisphere flow anti-clockwise.
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The Gulf Stream is an example of a warm current in the north-west Atlantic.
The Gulf Stream is an example of a warm current in the north-west Atlantic.
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Study Notes
Oceanic Circulation
- Oceans redistribute global energy, receiving ~⅔ of solar energy hitting Earth's surface.
- Oceans retain heat longer than land.
- Ocean currents transport ~25% of Earth's heat budget.
Ocean Currents
- Ocean currents are horizontal water movements.
- Warm currents move warmer water from lower latitudes (nearer equator) to higher latitudes (nearer poles).
- Cold currents move colder water from higher latitudes to lower latitudes.
- Temperature of water in currents depends on its comparison to typical temperatures at that latitude, not necessarily on absolute value.
- Driven by wind and thermohaline circulation.
How Ocean Currents Work
- Wind friction moves surface waters.
- Coriolis Effect deflects wind-driven currents right in the Northern Hemisphere and left in the Southern Hemisphere.
- Thermohaline: related to heat (thermo) and salinity (haline).
- Temperature and salinity affect water density (colder and saltier water is denser).
- Precipitation, evaporation, and river runoff influence salinity.
- Cold salt water (unlike fresh water) continues to become denser until freezing.
- Dense, cold, salty water sinks near Antarctica and Greenland.
- In Antarctica, brine left behind when sea ice forms makes water denser.
- In Greenland, warm, salty water becomes colder and denser than surrounding water.
- Horizontal currents flow from low to high density.
Pattern of Ocean Currents
- Currents flow in circular loops (gyres).
- Gyres are found in both hemispheres.
- Northern Hemisphere gyres flow clockwise; Southern Hemisphere gyres flow counter-clockwise.
- Strong, warm, poleward flows are concentrated along western edges of ocean basins. Examples include Gulf Stream, Kuroshio Current, Agulhas Current.
- Atlantic, Pacific, and Indian Ocean currents exhibit similar patterns, but the Atlantic has stronger vertical circulation.
- Southern Ocean currents have stronger, deeper flow eastward, with less noticeable poleward flow due to lack of landmasses connecting to Antarctica.
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Description
Explore the fascinating world of oceanic circulation and currents in this quiz. Learn how oceans play a critical role in redistributing global energy, the differences between warm and cold currents, and the effects of wind and thermohaline processes. Test your knowledge on this important aspect of Earth's climate system.
