oceans

Question 1

ekman transport

Answer 1

• wind drives movement of water at surface
• coriolis force drives movement of water beneath surface
• creates ekman spiral if plotted downwards
• net transport 90 degrees to right (N hemisphere) or left (S hemisphere) of wind direction

Question 2

geostrophic current

Answer 2

• current resulting from the balance of the coriolis and pressure-gradient force

Question 3

gyres

Answer 3

• surface only currents in open ocean basins
• clockwise in northern hemisphere, anticlockwise in s hemisphere
• low pressure bulge of water in the middle of gyres due to geostrophic flow

Question 4

deep ocean currents

Answer 4

• NADW and AABW
• long term large transfers of energy
• large influence on climate
• driven by a combination of temperature and salinity = thermohaline circulation

Question 5

north atlantic deep water (NADW)

Answer 5

• warm saline water from gulf of mexico pushed northwards by gulf stream
• cools so becomes more dense than less saline nordic sea so sinks
• maintains flow of north atlantic drift
• flows southwards, meeting colder and denser AABW in southern sea

Question 6

antarctic bottom water (AABW)

Answer 6

• very cold winds blow offshore from antarctic continent forming polynas (sea ice blown offshore)
• sea water supercooled and sea ice forms, rejecting salt into surrounding water
• forms extremely cold saline dense water which sinks to the bottom of the Southern ocean

Question 7

disruption to the nadw

Answer 7

• melting of the greenland ice sheet introduces large amounts of freshwater, diluting the dense salty water that makes up the NADW, could potentially disrupt NADW and deep ocean circulation
• would not disrupt gulf stream as determined by coriolis effect

Question 8

gulf stream

Answer 8

• transfer of energy north eastwards from gulf of mexico into the north atlantic drift
• causes differential weather conditions between canada and uk at same latitudes