Oceanic Currents Flashcards
How are the atmospheric and oceanic systems connected?
The atmospheric and oceanic systems are intimately connected in that the driving force for ocean currents is the frictional drag of the winds.
How dose the Coriolis effect affect ocean currents?
Because ocean currents flow over long distances, the Coriolis force deflects them. However, their pattern of deflection is not as tightly circular as that of the atmosphere.
What are ocean currents driven by
you can see that ocean currents are driven by the atmospheric circulation around subtropical high-pressure cells in both hemispheres.
What are gyres?
The oceanic circulation systems are known as gyres and generally appear to be offset toward the western side of each ocean basin.
What are Equatorial Currents
Trade winds drive the ocean surface waters westward in a concentrated channel along the equator . These equatorial currents remain near the equator because of the weakness of the Coriolis force, which diminishes to zero at that latitude.
What is Western intensification
The piling up of ocean water along the western margin of each ocean basin, to a height of about 15 cm; is produced by the trade winds that drive the oceans westward in a concentrated channel.
What bodies of water move as a result of western intensification?
In the Northern Hemisphere, the Gulf Stream and the Kuroshio (a current east of Japan) move forcefully northward as a result of western intensification.
What is an Upwelling current?
Upwelling current
An area of the sea where cool, deep waters, which are generally nutrient-rich, rise to replace vacating water, as occurs along the west coasts of North and South America. (Compare Downwelling current.)
What is a Downwelling current?
Downwelling current (6) An area of the sea where a convergence or accumulation of water thrusts excess water downward; occurs, for example, at the western end of the equatorial current or along the margins of Antarctica. (Compare Upwelling current.)
What is Thermohaline circulation?
Deep-ocean currents produced by differences in temperature and salinity with depth; Earth’s deep currents.
Differences in temperatures and salinity (the amount of salts dissolved in water) produce density differences important to the flow of deep currents on Earth known as thermohaline circulation, or THC (thermo- refers to temperature and -haline refers to salinity)
How would one picture the THC
To picture the THC, imagine a continuous channel of water beginning with the flow of the Gulf Stream and the North Atlantic Drift (Figure 6.18). When this warm, salty water mixes with the cold water of the Arctic Ocean, it cools, increases in density, and sinks. The cold water downwelling in the North Atlantic, on either side of Greenland, produces the deep current that then flows southward. Downwelling also occurs in the high southern latitudes as warm equatorial surface currents meet cold Antarctic waters (Figure 6.20). As water then moves northward, it warms; areas of upwelling occur in the Indian Ocean and North Pacific. A complete circuit of these surface and subsurface currents may require 1000 years.
