Drivers for circulation

Question 1

What drives ocean circulation?

Answer 1

• Force Balance
• Surface wind stress
• Buoyancy

Question 2

Forces modifying drivers for ciculation?

Answer 2

• Friction
• Coriolis force
• Tidal force

Question 3

Force balance

Answer 3

Force causes acceleration- when a ‘parcel’ of water is acted on by a force it will start moving faster

Question 4

Steady state situation

Answer 4

The sum of all forces acting at any instant must add up to zero

Question 5

Driver of surface-current ocean circulation

Answer 5

Wind-driven

Question 6

What determines density of seawater?

Answer 6

Salinity and temperature

Question 7

Decreasing temperature leads to…

Answer 7

Increasing density

Question 8

Increasing salinity leads to…

Answer 8

Increasing density

Question 9

Salinity range for seawater

Answer 9

25-40% typically 34-35%

Question 10

Buoyancy

Answer 10

• more dense sea water sinks
• Density increased by lower temp and higher salinity
• Jointly determines where and when water sink to greater depth

Question 11

1% salinity change…

Answer 11

Has similar effect on density as 4C temp change

Question 12

Density of pure water at 4C

Answer 12

1000kg/m3

Question 13

Density of seawater at 4C

Answer 13

1027kg/m3

Question 14

Acts once water is in motion, resisting its movement against surfaces or other water masses.

Answer 14

Frictional forces

Question 15

Smooth and orderly, governed by viscosity, while turbulent flow is chaotic and driven by factors like velocity and obstacles.

Answer 15

Laminar flow

Question 16

Crucial for laminar flow, determining how easily water molecules slide past each other.

Answer 16

Viscocity

Question 17

In turbulent flow…

Answer 17

Eddies form and mix water masses, with eddy viscosity influencing the redistribution of properties within the ocean.

Question 18

Tidal forces

Answer 18

Caused by the gravitational pull of the sun and moon

Question 19

Diffusion

Answer 19

Transport of heat/salinity through water without it moving- very inefficient

Question 20

Advection

Answer 20

Properties (heat/salinity) carried with water as it moves. Mixing only occurs faster than diffusion if the motion is TURBULENT