OCE1001 FSU Chapter 7

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

45 degrees to the left

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

80

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

Accidental spills from container ships

Western intensification causes:

All the above effects are the result of western intensification.

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

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

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 contributes to the South Eastern United States being humid?

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

Why is Antarctic Bottom Water so dense?

It is cold and salty.

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.

Warm ocean currents ___.

are warmer than the surrounding water

Downwelling can result from __________.

converging surface currents

Thermohaline circulation is driven by:

density differences.

Converging surface waters are areas of ________ and ________ productivity.

downwelling; low

Cool ocean currents ___.

generally flow from high latitudes towards the equator

Freezing seawater at _____ leads to increases in salinity and density

high latitudes

The subtropical gyres ___.

play a large role in climate

The Ekman spiral is caused by:

the wind and the Coriolis effect.

_____ is caused by density changes near the poles and equator.

thermohaline circulation

Deep ocean current movement is also known as __________.

thermohaline flow

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

to the left of the wind direction.

Equatorial currents are driven by the:

trade winds.

Under which conditions are droughts and wildfires common in Australia?

under El Niño conditions

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

upwelling.

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

western boundary currents

The image below is a block diagram showing the Pacific Ocean during an El Niño event. Correctly match the letters with the corresponding features.

C: high atmostpheric pressure E: Pacific warm pool A: thermocline B: walker circulation cell (reversed direction) D: low atmospheric pressure

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.

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

Mediterranean Intermediate Water (MIW)

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

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.

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

Two

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

Western Boundary Current

The thermocline is _________________.

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

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.

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

gravity and the Coriolis effect.

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

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

toward E

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

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

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

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

- Kuroshio Current - Brazil Current - the Gulf Stream

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

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

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

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

Surface ocean currents ___.

-Are driven by winds -Form large rotating gyres in the major ocean basins -Are influenced by Coriolis effect

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

-B -E -F

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

-C -n -H

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

-N -H

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

-Wind -Coriolis effect

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.

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

Using this image of the waters adjacent to the East Coast of the United States, match the correct letter to each of the following.

B: Cold core ring(s) C: Color for warm water A: Color for cold water D: warm core ring(s)

The following block diagram shows coastlines in the Northern Hemisphere that are influenced by coastal winds (not shown). Based on the flow of surface waters due to Ekman transport, identify the correct coastal wind direction in each diagram.

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

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.

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

South Equatorial Current

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

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

eddies

What is the Southern Oscillation?

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

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?

- 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.

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

Eastern Boundary Current

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

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

Which process causes downwelling off the coast of Antarctica?

ice formation

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

meanders

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

one-third

Deep ocean currents ___.

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

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

south; left

Waters along the California coast are colder than those along the mid-Atlantic shore of the U.S. because

Coastal Upwelling

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

Eastern Boundary Current

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

Ekman transport

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)

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

Somali Current

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.

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

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

decrease; increase

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

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

The El Niño Southern Oscillation can best be described as:

the relationship between sea surface temperature and changing atmospheric pressure.

The image below is a block diagram showing the Pacific Ocean during an El Niño event. Correctly match the letters with the corresponding features.

D: Antarctic Bottom Water C: Seasonally warm water B: Warmest water F: North Atlantic Deep Water E: Antarctic Intermediate Water G: Upwelling A: Thermocline and pycnocline

Use the map of Pacific and Atlantic Ocean currents shown below to correctly identify the following ocean currents and gyres.

D: Benguela Current C: Gulf Stream Current G: Peru Current A: Subpolar gyre B: Subtropical gyre E: California Current F: Canary Current I: Brazil Current H: Antarctic Circumpolar Current (West Wind Drift)

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

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

El Nino conditions

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