Chapter 7

Ocean surface currents transfer about ________ of the total amount of heat from the tropics to the poles.

one-third

Surface ocean currents ___.

are driven by winds form large rotating gyres in the major ocean basins are influenced by Coriolis effect

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. A: Color for cold water 2. B: Cold core ring(s) 3. D: Warm core ring(s) 4. C: Color for warm water

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. B: Wind blowing parallel to the coast and toward the bottom of the diagram 2. A: Wind blowing parallel to the coast and toward the top of the diagram

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. C: Gulf Stream Current 2. G: Peru Current 3. I: Brazil Current 4. D: Benguela Current 5. B: Subtropical gyre 6. A: Subpolar gyre 7. H: Antarctic Circumpolar Current (West Wind Drift) 8. F: Canary Current 9. E: California Current

To produce a surface current of 1.6 knots in the open ocean, a steady wind of _____ knots would be required.

80

Compared to an eastern boundary current in a gyre, which of the following statements is true for a western boundary current?

All the above statements are true of western boundary currents.

Recall that global winds impact the direction of surface ocean currents. Examine the following map showing the Atlantic Ocean off the west coast of Africa. The direction of the surface current and the prevailing wind do not coincide. What can explain this discrepancy?

Because the current is located in the Southern Hemisphere, the subtropical gyre pulls the current in a counterclockwise direction. The Coriolis effect deflects ocean currents in the Southern Hemisphere to the left due to Earth's rotation.

What factor(s) drive(s) Ekman transport?

Coriolis Effect Wind

The thermocline is _________________.

a steep temperature gradient in the ocean that separates deeper cold water from warmer upper water

In the figure above, which shows a cross section of the Atlantic Ocean extending from Greenland (north) to Antarctica (south). Which labeled layer has the highest density?

G

Which of the following currents contributes to the South Eastern United States being humid?

Gulf Stream

Which process causes downwelling off the coast of Antarctica?

Ice formation

Of the following locations, where would upwelling be expected to occur? Choose all that apply.

In areas of diverging surface currents Where seamounts or tablemounts are present Where there is a sharp bend in a coastline

Which of the following methods are used to measure ocean surface currents indirectly?

Pressure gradients

Which of the following methods are used to measure ocean surface currents directly?

Radio-transmitting float bottles

Between summer and winter, which of the following currents reverses its flow direction?

Somali Current

Which of the following Atlantic Subtropical gyre boundary currents is split into two by a large landmass?

South Equatorial Current

Coastal upwelling along the coast of Chile is a result of winds from the ________ turning towards the ________ due to Ekman transport.

South left

Which of the following statements is true of surface ocean currents?

Surface currents form circular patterns in the major ocean basins called "gyres."

Judge the following sentence according to the criteria given below: India's Southwest Monsoon provides abundant precipitation BECAUSE the air brought in from the Indian Ocean is warm and full of moisture.

The assertion and the reason are both correct, and the reason is valid.

Judge the following sentence according to the criteria given below: The Equatorial Countercurrent is much better developed in the Pacific Ocean than in the Atlantic BECAUSE the Pacific Ocean basin is larger and more unobstructed than the Atlantic Ocean.

The assertion and the reason are both correct, and the reason is valid.

Judge the following sentence according to the criteria given below: The temperatures across the Atlantic at different latitudes are much higher in Europe than in North America BECAUSE of the effects of heat transfer from the Gulf Stream.

The assertion and the reason are both correct, and the reason is valid.

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.

Converging surface waters are areas of ________ and ________ productivity.

downwelling; low

Equatorial currents that are part of the subtropical gyres flow ___. Equatorial counter currents between the gyres flow ___ .

east to west; west to east

Which direction do ocean currents in the South Pacific move under El Niño conditions?

eastward

During winter months, monsoon winds over the Indian Ocean:

flow from land to sea and are dry.

Deep ocean currents ___.

result from changes in water density (due to temperature and salt content)

The Ekman spiral is caused by:

the wind and the Coriolis effect.

Deep ocean current movement is also known as __________.

thermohaline flow

Refer the figure above. In which direction would the entire surface current underneath the Greenland iceberg be expected to travel?

toward E

Under which conditions are droughts and wildfires common in Australia?

under El Niño conditions

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. C: High atmospheric pressure 2. D: Low atmospheric pressure 3. A: Thermocline 4. E: Pacific Warm Pool 5. B: Walker Circulation Cell (reversed direction)

Which of the following methods are used to measure ocean surface currents directly?

Accidental spills from container ships

In the figure above, which of the labeled currents are eastern boundary currents?

H C N

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. G: Upwelling 2. F: North Atlantic Deep Water 3. C: Seasonally warm water 4. B: Warmest water 5. A: Thermocline and pycnocline 6. E: Antarctic Intermediate Water 7. D: Antarctic Bottom Water

Based on the graph, which of the following has the lowest temperature?

Antarctic Bottom Water (AABW)

Which of the following is the only current that completely circumscribes Earth?

Antarctic Circumpolar

Of the following surface currents, which one(s) transport large volumes of warm water to higher latitudes? Choose all that apply.

Brazil Current the Gulf Stream Kuroshio Current

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.

The California Current is an example of which of the following types of currents?

Eastern Boundary Current

In the figure above, which of the labeled currents are warm water currents?

F E B

One of the world's most powerful currents, located off the east coast of the United States, is the __________.

Gulf Stream

Which ocean current is the strongest and fastest ocean current in the world?

Gulf Stream

Which of the following currents is responsible for Peru becoming the largest producer of fish, from the sea, in the world?

Humboldt Current

Of the following gyres, which one(s) flow in a counterclockwise direction? Choose all that apply.

Indian Ocean Subtropical Gyre Northern Hemisphere Subpolar Gyres South Atlantic Subtropical Gyre South Pacific Subtropical Gyre

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.

Fluctuations in the flow of the Gulf Stream current result in curving loops of water known as __________.

Meanders

Based on the graph, which of the following has the highest salinity?

Mediterranean Intermediate Water (MIW)

In the figure above, which of the labeled currents are shallow, weak, and slow currents?

N H

The Gulf Stream transports warm water into the __________.

North Atlantic

Based on the graph, which of the following has the lowest density?

North Atlantic Central Surface Water (NACSW)

Equatorial currents are driven by the:

Trade winds

Western intensification causes:

Western intensification causes:

Which of the following two factors cause geostrophic circulation within a gyre?

Which of the following two factors cause geostrophic circulation within a gyre?

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.

Warm ocean currents ___.

are warmer than the surrounding water

When a meander from the Gulf Stream pinches off into the warm water south of the current, the eddy is called a __________.

cold-core eddy or ring

Downwelling can result from __________.

converging surface currents

An increase in seawater density can be caused by a ________ in temperature or a/an ________ in salinity.

decrease; increase

Thermohaline circulation is driven by:

density differences.

Which force(s) drive(s) water circulation in the deep ocean?

differences in water salinity differences in water temperature differences in water density

Cool ocean currents ___.

generally flow from high latitudes towards the equator

The El Niño Southern Oscillation can best be described as:

the relationship between sea surface temperature and changing atmospheric pressure.

What is the Southern Oscillation?

the swapping of high and low pressure zones in the South Pacific under El Niño conditions

The Benguela Current is an example of which of the following types of currents?

Eastern Boundary Current

Why is Antarctic Bottom Water so dense?

It is cold and salty.

The subtropical gyres ___.

play a large role in climate

Match the words in the left column to the appropriate blanks in the sentences on the right. Some terms will remain unused.

1. Palm trees associated with the subtropics can be found at the northern tip of the British Isles in Scotland. This is due to the transfer of heat from the North Atlantic current. 2. Thermohaline circulation is caused by density changes near the poles and equator. 3. Waters along the California coast are colder than those along the mid-Atlantic shore of the U.S. because coastal upwelling occurs as surface waters move away from the coast. 4. Freezing seawater at high latitudes leads to increases in salinity and density.

In which direction does the surface current move in relation to the wind in the Southern Hemisphere?

45 degrees to the left

In the figure above, which shows a cross section of the Atlantic Ocean extending from Greenland (north) to Antarctica (south). Which labeled layer represents a cold-water mass mixing with warmer water to create a water mass with intermediate density?

E

Of the following statements about the Ekman spiral and Ekman transport, which is/are true? Choose all that apply.

Ekman transport can result in both upwelling and downwelling. Ekman transport is to the right of the wind direction in the Northern Hemisphere. In the deeper layers of the Ekman spiral, water can move in a direction opposite of the wind direction. The Coriolis effect causes surface waters to move at an angle relative to the wind direction

The false-color map of sea surface temperatures shown below is an example of which of the following features?

El Nino conditions

Which current that flows along the equator is driven by a difference in sea level caused by ocean circulation patterns?

Equatorial Countercurrent in the Pacific Ocean

Which of the following methods are used to measure deep ocean currents directly?

Free-drifting Argo floats

The observation of a hill of water within all subtropical gyres is an example of which of the following?

Subtropical convergence

The Brazil Current is an example of which of the following types of currents?

Western Boundary Current

About what percent of the wind's energy is transferred to the ocean surface?

Two

Surface waters are pushed away from land and replaced by nutrient-rich bottom water through:

Upwelling

The Kuroshio (Japan) Current is an example of which of the following types of currents?

Western Boundary Current

Records indicate that the ocean is warming faster in the Arctic polar regions than elsewhere. If that continues, a possible consequence could be __________.

slowing of deep ocean circulation, resulting in lower oxygen levels in deep water

In the southern hemisphere, the direction of Ekman transport is always:

to the left of the wind direction.

Ocean frontal systems that spin off from currents such as the Gulf Stream, akin to atmospheric storms, are known as __________.

Eddies

Coastal winds can cause upwelling or downwelling due to which of the following?

Ekman transport

The observation that ships and icebergs in the southern hemisphere float to the left of the wind direction is an example of which of the following?

Ekman transport

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

In the figure above, depicting 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?

toward D

Warm core rings and cold core rings are associated with __________.

western boundary currents