Ocean Circulation

Question 1

Two types of Ocean Currents:
- Surface Circulation, Wind driven
- Thermohaline Circulation, Gravity or Density Driven

Answer 1

• Surface Current
• Deep Water Current

Question 2

Surface Currents move water ____ and occur in ocean’s surface waters within and above the ____ to a depth of ~1km (make up 10% of ocean)

Answer 2

Horizontally, Pycnocline

Question 3

Surface currents closely follow _____. Trade winds at 0-30 degree latitude blow surface currents to the ____ while prevailing westerlies at 30-60 degree latitude blow currents to the ____.

Answer 3

Global wind belt pattern, east, west

Question 4

Surface Currents generally mirror average planetary ______.

Answer 4

Atmospheric Circulation Patterns

Question 5

_____ develop from friction between the ocean and the wind that blows across its surface. Only ___ of the wind’s energy is transferred to the ocean surface. They are driven by wind and also distribution of continents on earth.

Answer 5

Surface Currents, 2%

Question 6

Equatorial currents travel westward along the equator and form the equatorial boundary current of _____. Each Gyre is composed of 4 main currents:

Answer 6

Subtropical Gyres:
- Equatorial Currents
- Western Boundary Currents
- Northern and Southern Boundary Currents
- Eastern Boundary Currents

Question 7

6 Great Current Circuits in the World Ocean:

Answer 7

• North Atlantic Gyre
• North Pacific Gyre
• South Atlantic Gyre
• South Pacific Gyre
• Indian Ocean Gyre
• West Wind Drift or Antarctic Circumpolar Current

Question 8

A current of any fluid forming on the side of a main current; usually moves in a circular path; develops where currents encounter obstacles or flow past one another. Swirling.

Answer 8

Eddy

Question 9

More apparent in Pacific because of dome of equatorial water that becomes trapped in the island-filled embayment between Australia and Asia; western basin 2m higher than eastern basin

Answer 9

Equatorial Countercurrents

Question 10

Driven in a westerly direction by polar easterlies, smaller and fewer, best developed in Atlantic Ocean between Greenland and Europe, and Weddell Sea

Answer 10

Subpolar Gyres

Question 11

Other Factors affecting ocean surface circulation:

Answer 11

• Ekman Spiral and Ekman Transport
• Geostrophic Current
• Western Intensification of Subtropical Gyres

Question 12

Surface currents move at angle to wind. Describes speed and direction of seawater flow at different depths. Each successive layer moves increasingly to right (N hemisphere)

Answer 12

Ekman Spiral

Question 13

All the layers combine however create a net water movement that is 90deg from the direction of the wind. In shallow coastal waters, _____ may be very near the same direction as the wind.

Answer 13

Ekman Transport

Question 14

Net transport of water as an effect of steady blowing wind; theoretically 90 degrees to the right of wind direction in the Northern Hemisphere and 90 degrees to the left of wind direction in the Southern Hemisphere

Answer 14

Ekman Transport

Question 15

The process by which deep, cold, nutrient-laden water is brought to the surface, usually by diverging equatorial currents or coastal currents that pull water away from the coast

Answer 15

Upwelling

Question 16

Ekman transport piles up water within subtropical gyres. Surface water flows downhill (gravity) and
Also to the right (Coriolis effect). Balance of downhill and to the right causes ____ around the “hill”.

Answer 16

Geostrophic Flow

Question 17

Top of hill formed within rotating gyre is closer to western boundary than the center. Western boundary currents of gyre is faster, narrower and deeper than eastern boundary current counterparts.

Answer 17

Western Intensification of Subtropical Gyres

Question 18

Current convergence occurs when surface waters pile up. When currents converge, no place to go but downwards.

Answer 18

Converging Surface Seawater

Question 19

A cellular circulation set up by winds that blow consistently in one direction with speeds in excess of 12 km/hr. Helical spirals (convection cells) running parallel to the wind direction are alternately clockwise and counterclockwise.

Answer 19

Langmuir Circulation

Question 20

Previously warm,
salty water, transported
to low S. latitudes, cooled
and downwelled at the
Antarctic Convergence.

Answer 20

Thermohaline Circulation

Question 21

For every ___of deep water formed, ___ liter of deep water must upwell

Answer 21

One

Question 22

Combination deep ocean currents and surface currents

Answer 22

Conveyor-Belt Circulation

Question 23

Youngest Circulation and Oldest Current Circulation found in what areas respectively?

Answer 23

Atlantic Ocean and Pacific Ocean

Question 24

Masses of air that move across earth’s surface from subtropical high-pressure belts toward equatorial low-pressure belt

Answer 24

Trade Winds

Question 25

Move from NE to SW, curve to the right due to Coriolis

Answer 25

NE Trade Winds

Question 26

Move the SE to NW, curve to the left due to Coriolis

Answer 26

SE Trade Winds

Question 27

Some of air that descends in subtropical regions moves to higher latitudes as the _____? (blow from SW to NE in N Hem, and from NW to SE in S Hem)

Answer 27

Prevailing Westerly Wind Belts

Question 28

Coriolis effect maximized at high latitudes

Answer 28

Polar Easterly Wind Belts

Question 29

Trade winds which blow from the SE in the S Hem and from the NE in the N Hem set in motion water masses between the tropics resulting in ________. They travel westward along the equator and form the equatorial boundary current of the gyres.

Answer 29

Equatorial Currents

Question 30

• Fastest and deepest geostrophic currents found on the western boundaries of ocean basins
• Narrow, fast, deep currents move warm water poleward in each of the gyres
• Gulf Stream (N Atlantic), Kuroshio (N Pacific), Brazil (S Atlantic), Agulhas (Indian), East Australian (S Pacific)

Answer 30

Western Boundary Currents

Question 31

• Opposite of western boundary currents
• Carry cold water equatorward
• Shallow and broad
• Canary (N Atlantic), California (N Pacific), Benguela (S Atlantic)

Answer 31

Eastern Boundary Currents

Question 32

The____, named in honour of the pioneering oceanographerHarald Sverdrup, is aunit of measureofvolumetransport.

Answer 32

Sverdrup

Question 33

• When currents converge, no place to go but downwards called ______.
• Low biological productivity

Answer 33

Downwelling