oce exam 2 - ch 7

Surface ocean currents

*Created by friction between the ocean and the wind that blows across its surface. *Can be localized and short-lived or relatively permanent that extend across large areas.

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

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

Of the following statements about the Ekman spiral and Ekman transport, which is/are true?

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

Western intensification causes: very swift western boundary currents. a steeper slope of surface water in the western section of the gyre as compared to the eastern section of the gyre. the center of the gyre to be shift to the west. a large volume of water to flow within western boundary currents.

*very swift western boundary currents. *a steeper slope of surface water in the western section of the gyre as compared to the eastern *the center of the gyre to be shift to the west. *a large volume of water to flow within western boundary currents.

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 - 1.6 knots is 2% of 80

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

Brazil Current Kuroshio Current the Gulf Stream

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

Coriolis effect + wind

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 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

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

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

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.

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

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

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

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.

Deep ocean current movement is also known as __________.

Thermohaline flow

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

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.

all correct and valid

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

antarctic circumpolar

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

Downwelling can result from __________.

converging surface currents

India's Southwest Monsoon provides abundant precipitation BECAUSE the air brought in from the Indian Ocean is warm and full of moisture.

correct + valid

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.

correct + valid

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

Converging surface waters are areas of ________ and ________ productivity.

downwelling - low

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

eastward

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

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 + coriolis effect

Surface ocean currents are part of large, slow-moving loops of water known as

gyres

Which process causes downwelling off the coast of Antarctica?

ice formation

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

increased current velocity narrower current deeper current warmer water

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

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

meanders

The Gulf Stream transports warm water into the __________.

north atlantic

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

one-third

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, accidental spills from container ships

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

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

south/left

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

subtropical convergence

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

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

to the left of the wind direction

Equitorial currents are driven by:

trade winds

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

two

Under which conditions are droughts and wildfires common in Australia?

under el nino conditions

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

western boundary

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

western boundary current

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

western boundary currents

The Ekman spiral is caused by:

wind + coriolis effect