Quiz 29 oct

Question 1

What is a mass flow of ocean water driven by?

Answer 1

wind and gravity

Question 2

What is occuring at the friction depth?

Answer 2

At the friction depth, water will flow in the opposite direction from the surface current

Question 3

What are the six great current circuits in the ocean and which ones are geostrophic gyres?

Answer 3

There are 6 great current circuits in the ocean: 5 of them are geostrophic gyres:

North and South Atlantic gyres,
North and SouthPacific gyres
and Indian Ocean gyre.

The last one is called the West Wind Drift

Question 4

What are geostrophic currents?

Answer 4

The currents that form a geostrophic gyre. WET

1-Western boundary
2-Eastern boundary
3-Transverse

Question 5

What are the characteristics of Western boundary currents?

Answer 5

• Fast, deep currents that move warm water poleward in each of the gyres

-Great volume of water, measured in sverdrups (sv) = 1 million cubic meters per second

• Water in western boundary currents (WBC) can move for long distances within well-defined boundaries
• WBC form meanders as they flow poleward
• Eddies

Question 6

What are the characteristics of Eastern boundary currents?

Answer 6

• Eastern boundary currents
• Shallow, broad, with ill-defined boundaries
• Carry cold water toward the equator • Shallow and broad (up to 1000 km)
• Eddies tend not to form
• Carry much less water that WBC

Question 7

What are eddies? What is the difference between cold-core eddies and warm-core eddies?

Answer 7

eddies: turbulent rings formed by connected looping meanders. They trap cold or warm water in their centers and separate from the main flow

• 2 types: cold-core Eddies (rotate counterclockwise) and warm-core Eddies (rotate clockwise)

Question 8

How much of the North Atlantic may consist of old cold-core eddies?

Answer 8

1⁄4

Question 9

What is wind-induced vertical circulation?

Answer 9

Vertical movement induced by wind-driven horizontal movement of water:

Question 10

What is upwelling?

Answer 10

• Upwelling: upward motion of water

* Brings cold, nutrient-rich water toward the surface

Question 11

What is downwelling?

Answer 11

• Downwelling: downward motion of water

* Supplies the deeper ocean with nutrients and dissolved gases

Question 12

What is Equatorial upwelling?

Answer 12

when water moving on either side of the Equator is deflected slightly poleward (Coriolis effect) and replaced by ascending nutrient-rich deeper water

Question 13

What is coastal upwelling?

Answer 13

Coastal upwelling: occurs when this surface water is replaced by water rising from the bottom along the shore (coast)

Question 14

What is thermohaline circulation?

Answer 14

Thermohaline circulation: Movement of water driven by differences in density (temperature and/or salinity) involving the whole ocean

Question 15

What does the flow of water in the conveyor belt distribute?

Answer 15

• The flow of water in the conveyor belt distributes dissolved gasses, solids, nutrients and larvae of different organisms among ocean basins

Question 16

What are the different ways currents are studied?

Answer 16

SDAT
• Surface currents traced with drift bottles or drift cards

-Drifting Buoys can be tracked continuously by radar or radio direction finders (or gps)

• Argo system floats: autonomous drifting sensors that move vertically (up to 2000 m) measuring temperature and conductivity in their path. Data uploaded to a satellite to calculate salinity and other parameters.

-Tracking movement of chlorofluorocarbons (CFCx)

Question 17

What is the greenhouse effect?

Answer 17

• The Greenhouse effect is a natural phenomenon which allows keeping Earth’s surface at a habitable average temperature, which was 14oC before the industrial revolution

is a process that occurs when gases in Earth’s atmosphere trap the Sun’s heat. This process makes Earth much warmer than it would be without an atmosphere.

Question 18

How are currents classified & describe each one

Answer 18

STG
• Surface currents
• Wind-driven movements of water at or near the ocean’s surface

Thermohaline currents
• Slow, deep currents (depending on density differences caused by variations in temperature and salinity) that affect the vast bulk of seawater beneath the pycnocline

• Geostrophic currents: the currents (with different characteristics) that form a geostrophic gyre

Question 19

Explain the Ekman spiral

Answer 19

Ekman spiral: deflection of surface currents caused by wind in which the flow direction rotates as one, moves away from the initial contact surface boundary.

Question 20

What are gyres?

Answer 20

Gyre: Current flow around the periphery of an ocean basin

Question 21

Types of water masses?

Answer 21

SCIDB

• Surface water: up to 200 m deep
• Central water: to the bottom of the main thermocline (below 1000 m in mid- latitudes)
• Intermediate water: up to 1500 m deep
• Deep water: between IW and up to 4000 m. Not in contact with the bottom
• Bottom water: in contact with the sea floor