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43 Cards in this Set

  • Front
  • Back
What are the 2 types of ocean currents?
1. wind driven surface currents

2. density driven deepwater currents
What drives ocean currents?
Pattern of global winds
Explain vertical circulation in the ocean.
Inherently stable. SLOW vertical circulation. Heated at upper surface.
The high heat capacity of water gives the ocean what characteristic?
An almost uniform temp. & density, laterally speaking.
What is density affected by?
1. temperature
2. salinity
3. pressure
At what depth does pressure become an important factor in density?
>1,000 ft
Where is the ocean the most and least salty?
Most salty at equator & poles.
Least likely at middle latitudes.
How does heating water affect density?
changes mass of water per unit volume.
increases evaportation, which increases salinity.
What does water motion influence?
1. Distrivution of energy and material
2. Global climate
3. Marine environments
What are surface currents due to?
1. Wind stress
2. Density differences by insolation
3. Coriolis
4. Land mass distribution
What is the name for the unit of ocean current circulation?
How do the gyres flow?
towards the equator, towards the poles, away from 60 degrees N and S.
What does the Ekman Spiral theory predict?
1. Ekman spiral turn to the right
2. flow reversed at 100 m
3. the net flow is towards the center of the spiral
4. speed is reduced at greater depth
What is a mound?
where the water rises up in the middle of an Ekman spiral
What is a geostrophic current?
at certain heights, the water flows perfectly parallel to Ekman spiral
What is the convergence zone?
In an Ekman spiral, it's the area beneath where the flow reverse and water is pushed outwards
How do the major gyres of each hemisphere move?
What is western intensification?
When the current flow of a gyre is off center to the west to make up for the friction along a coast.
What is vorticity?
The tendency of fluids to rotate
What sre the three types of vorticity and decribe their differences.
planetary vorticity: due to coriolis

relative vorticity: due to spiral surface winds and current shear

absolute vorticity: both
What is current shear?
current speed changes across a current.
What are the pos/neg vorticity values?
postive = counterclockwise

negative = clockwise
W/o regard to hemisphere and in a symmetric circulation, describe the vorticities of the different current flows.
Northrward would be neg.

Southward would be pos.
Where do oceans get salt from?
rocks weathering, volcanic dust
What property of salinity is conserved?
The ratio of major dissolved ions to each other is constant
Variations in salinity are due to...?
evaporation, precipitation, mixing
Density currents are also known as...?
Thermohaline currents (temp and salt!)
How do temp and salinity affect density?
temp down, density up
salinity up, density up
What are the 3 layers in the vertical structure of the ocean?
1. surface zone
2. Pycnocline zone
3. deep ocean
What are the characteristics of the surface zone?
mixed layer
little changes in temp & density w/ depth.
What are the characteristics of the pycnocline zone?
density increases rapidly with depth, due to rapid salinity increase and temperature decrease
What are the halocline and thermocline?
areas were salinity and temperature increase and decrease, respectively
What are the chracteristics of deep ocean?
little change in density w/ depth
Explain bottom water circulation.
water at bottom is most dense.
pole bottom water is densest of all.
water moves from high to lower density.
as warmer water moves up to poles, it gets cooled down to bottom water and pushed away.
circulated all over the world
What are the two significant types of bottom water?
North Atlantic and Antarctic bottom water
What are the chracteristics of a water mass?
large volume
common origin
How are water mass formed?
1. interaction with the atmosphere
2. mixing of 2 bodies of water
what is the mixing rate of water and how does it affect the density?
water mixes slowly, so it retain its temp and salinity
What does the identification of water masses give us info about?
1. place of origin
2. deep water circulation
3. rate of mixing
What data is used to identify water masses?
1. temp
2. salinity
3. oxygen content
What are isopycnals?
Contours of equal density
If 2 waters types with the same density but different temps and salinities are mixed, what's the result?
Denser water than both
What is caballing?
mixing of 2 water masses of identical densities but different temps and salinities.