ch 7 oceanography
The direction of the surface current and the prevailing wind do not coincide. What can explain this discrepancy?
- The Coriolis effect deflects ocean currents in the Southern Hemisphere to the left due to Earth's rotation - Because the current is located in the Southern Hemisphere, the subtropical gyre pulls the current in a counterclockwise direction
what causes upwelling
- Wind blowing parallel to the coast and toward the bottom of the diagram - ekman flow back towards the deep ocean bringing coastal surface waters with it and replacing w cold deepwater
what causes downwelling
- Wind blowing parallel to the coast and toward the top of the diagram - ekman flow towards the coast bringing in warm surface waters, pushing down previous
What factor(s) drive(s) Ekman transport?
- coriolis effect - wind
Which factor(s) below drive(s) and shape(s) the pattern of surface ocean currents?
- coriolis effect - wind - shape of the ocean basins
Which force(s) drive(s) water circulation in the deep ocean?
- differences in water salinity - differences in water temperature - differences in water density
In the Northern Hemisphere, the Ekman spiral moves layers of water to the _____ of the wind direction and Ekman transport (the overall direction of water movement) is to the _____.
- right - right
freezing seawater at high latitudes leads to increases in _______ and _______
- salinity - density
In which direction does the surface current move in relation to the wind in the Southern Hemisphere?
45 degrees to the left
area of cold water in picture
A
thermocline
A
thermocline and pycnocline
A
Walker Circulation Cell
B
cold core rings in picture
B
warmest water
B
area of warm water in the picture
C
high atmospheric pressure
C
seasonally warm water
C
antarctic bottom water
D
low atmospheric pressure
D
warm core rings in the picture
D
Why do the lengths of the arrows in the Ekman spiral get shorter and shorter as you move deeper into the water column?
Deeper water moves at a slower speed due to friction
Pacific Warm Pool
E
antarctic intermediate water
E
Why are western boundary currents intensified compared to eastern boundary currents?
Earth rotates from west to east, pushing water more strongly toward the west.
north atlantic deep water
F
upwelling
G
Why is Antarctic Bottom Water so dense?
It is cold and salty
What is the Walker Circulation Cell?
It is the path that air takes as it moves from high to low pressure, and back to high pressure, in the South Pacific under normal conditions.
What would you expect weather to be like on the eastern coast of Australia if the western coast of South America were experiencing unusually warm, wet weather?
The eastern coast of Australia would be experiencing unusually dry weather.
Which of the following currents goes all the way around the world without being interrupted by land?
West Wind Drift
Why does upwelling occur along the west coast of South America under normal conditions?
Winds moving westward in the South Pacific drive ocean currents toward the west; deep water rises to replace water driven westward.
The thermocline is _________________.
a steep temperature gradient in the ocean that separates deeper cold water from warmer upper water
thermohaline circulation is caused by:
density changes near the poles and equator
Which direction do ocean currents in the South Pacific move under El Niño conditions?
eastward
In which direction would the entire surface current underneath the Greenland iceberg be expected to travel?
farther right than the surface
Which process causes downwelling off the coast of Antarctica?
ice formation
Currents and gyres
know the location and direction of currents and gyres respectively
What is the overall effect of the stronger than normal trade winds typical of La Niña conditions?
lowering of the South Pacific ocean temperature from normal conditions
a hypothetical wind direction in an ideal world. The iceberg broke off from the Greenland Ice Sheet and floated into the ocean. Under the prevailing wind conditions, in which direction would the iceberg be pushed?
slightly 45 degrees to the right
What is the Southern Oscillation?
the swapping of high and low pressure zones in the South Pacific under El Niño conditions
Under which conditions are droughts and wildfires common in Australia?
under El Niño conditions
