Ocean Currents Flashcards
Define Deep Currents
High density caused by temperature and salinity differences at the surface
What are the three methods to indirectly measure water currents?
Internal density distribution, TOEX/Posidon satellite to determine ocean bulges, Doppler flow meter to transmit low frequency sound signals
What two methods directly measure ocean currents?
A floating device is released and tracked through time, a fixed contraption measures flow through a propeller
How much of the wind’s energy is transferred to the ocean surface?
2 percent
What pattern would surface currents follow if there were not any continents on Earth?
The wind belts
Surface currents occur within and above the _____.
pychnocline (layer of rapidly changing density)
How deep do surface currents exist?
One Kilometer
How much of the world’s ocean water is affected by surface currents?
Ten percent
What currents are encouraged by the trade winds?
The N or S equatorial currents
What are western boundary currents and what contributes to them?
Currents traveling along the western current of their basin, Coriolis effect
What current flows south on the eastern edge of South America?
Brazil Current
What current flows north along the eastern edge of North America?
Gulf Stream
What current is warm and cold and exist on the southern edge of Alaska?
Alaskan Current
What current flows North along the western coast of South America?
Peru Current
Which current flows South along the western coast of North America?
California Current
What current flows North Across the northern Atlantic and is warm?
N. Atlantic Current
What current flows north up the lower eastern coast of South America and is cold?
Falkland Current
The Canary Current flows where and is what type of current?
South off of the coast of Europe and northern coast of Africa, cold
What current flows north off of the southwestern coast of Africa and is cold?
Benguela Current
What current flows south on the eastern coast of Africa and is warm?
Agulhas Current
What warm currents exist in the southern part of the Indian Ocean?
N. Equatorial Current flowing West, E. Equatorial Current flowing East, S. Equatorial Current flowing West
What current flows near the western coast of Australia coming from the Antarctic Circumpolar Current and goes North, and is cold?
W. Australian Current
What current flows south off of western coast of Australia and is warm?
Leeuwin Current
What current flows south near the eastern coast of Australia and is warm?
E. Australian Current
What current flows north off of the coast of Asia and is warm?
Kuroshio Current
What current flows south off of the northern coast of Asia and comes from the Arctic cold waters and is cold?
Oyashio Current
What is a subpolar Gyre?
currents that rotate opposite the adjacent subtropical gyre
The equatorial, western boundary, prevailing westerly, and eastern boundary currents combine to create a ______.
Subtropical Gyre
Who observed that the Arctic Ocean ice moved 20 to 40 degrees to the right of the wind blowing across the surface and on what voyage was he on?
Fridtjof Nansen, Fram
Who developed a circulation model called the Ekman spiral?
V. Walfrid Ekman a Swedish physicist
What is the Ekman spiral caused by?
the wind blowing across the surface and is modified by the Coriolis effect.
The _____ describes the speed and direction of flow of surface waters at various depths.
Ekman spiral
The movement of water 90 degrees to the right in the Northern Hemisphere and 90 degrees to the left in the Southern Hemisphere is the?
Ekman Transport
Western Intensification is what?
The phenomena that as a result of the western boundary of the subtropical gyres the western currents are faster and narrower than their eastern counterparts
_____ is the vertical movement of cold, deep, nutrient-rich water to the surface
Upwelling
_____ is the vertical movement of surface water to deeper parts of the ocean
Downwelling
_____ is dominated by the movement of water masses in the southern Atlantic, Indian, and Pacific.
Antarctic circulation
The Antarctic Circumpolar Current is also called the what?
West Wind Drift
The East Wind Drift is what?
a surface current propelled by the polar easerlies
The Antarctic Divergence is caused by what two surface currents?
East Wind Drift and Antarctic Circumpolar Current
T or F: The Antarctic Divergence as an abundance of Marine life in the Southern Hemisphere?
True
The Gulf Stream gradually merges eastward with the water of what sea?
Sargasso
Snake-like bends in the current that often disconnect from the Gulf Stream and form large rotating masses of water are called?
Meanders, Vortexes, Eddies, or Rings
What current plays a large role in moderating climate in the North Atlantic?
Gulf Stream
What is the name of the atmospheric circulation cell in the South Pacific?
Walker Circulation Cell
On the pacific edge of South America what is the climate due to the high pressure and sinking air?
Clear, fair, and dry
The Ekman transport moves water away from shore, causing upwelling of cool nutrient rich water. Where does this occur most famously?
Along the Peru Current
What warm-current phenomena occurs next to the coast of Peru every few years?
El Nino otherwise known as Southern Oscillation Conditions
What cold-current phenomena occurs next to the coast of Peru every few years?
La Nina
What phenomena are oceanographers recently associating with El Nino and La Nina?
Pacific Decadal Oscillation (PDO)
How long does the PDO last?
20 to 30 years
The Tropical Ocean-Global Atmosphere (TOGA) was initiated to study what?
El Nino events
Deep ocean circulation is also known as?
Thermohaline
A what can be used to identify deep-water masses based on their characteristics?
temperature-salinity diagram (T-S)
The densest part of the ocean is where and what?
Antarctic Bottom Water
What model represents the circulation of Antarctic and Atlantic water?
Conveyor-Belt Circulation
T or F: Cold water can dissolve more gases than warm water
True
From 1954 to 2004 the temperature of the surface water has increased by how much?
An average of .06 degrees celsius
