Unit 5 - Surface currents

Question 1

Circulation model of surface water

Answer 1

• Oceanic waters heat up due to Solar Radiation, becoming less dense.
• Warm, less dense water moves above the cold, denser water and gives off heat to surrounding waters.
• As this water cools, it sinks, taking the place of warmer water.
• This creates convection currents, which cause the circulation of surface water.

Question 2

Western Boundary Currents

Answer 2

• Narrow, deep, fast
• On the western boundaries of ocean basins
• Carries water, therefore heat from equator to poles

Question 3

Eastern Boundary Currents

Answer 3

• Return flow of western boundary currents
• Shallower, broader, colder and slower than western boundary currents.
• Moves from the poles to the equator.
• Driven by westerly winds

Question 4

Transverse currents

Answer 4

• At the equator, called the North and South equatorial currents.
• Flow from East to West on each side of the equator, driven by the Easterly Trade Winds
• Closes the tops and bottoms of gyres

Question 5

Counter currents

Answer 5

• Type of transverse urrent.
• Seperates the subtropical gyres in each hemisphere
• Narrow, Eastward flowing