Ocean Circulation

Why is Antarctic Bottom Water so dense?

It is cold and salty.

The largest of the great ocean surface currents is the

West Wind Drift

There are two parts to this question. This image depicts four atmospheric pressure cell patterns that have developed along various coastlines in the Southern Hemisphere. The dotted line represents the coastline; the ocean and land are labeled in each image. Use this image to answer the following questions. You may want to copy each selection to a scrap sheet of paper and draw on it to help answer the question. Identify the patterns (by letter) which depict a coastline that will experience upwelling? Check all that apply. Which patterns will produce a coastline whose sea surface height profile is higher near the coast and lower offshore? Check all that apply.

upwelling: b and c height profile: a and d

Indian Ocean currents that are generated by seasonal changes in weather patterns are the __________ and __________ Currents.

Somali/Southwest Monsoon

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

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

During a strong El Nino event, the news media might be expected to cover __________.

a tropical cyclone in Hawaii or Tahiti

Which factors below drive or shape the pattern of surface ocean currents? Check all that apply.

shape of the ocean basins Coriolis effect wind

Warm core rings and cold core rings are associated with

western boundary currents

The letters in the image below identify various locations within the North Pacific subtropical gyre and the Pacific equatorial circulation systems. Please match the letter from the image with the appropriate description.

which of the labeled currents is the slowest? c which current results from the geostrophic response to an accumulation of water in the western equatorial Pacific? b this labeled current is generated as a result of the surface Ekman response to the northeast trade winds? d which of the labeled currents is the fastest? e

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

Of the following statements about deep-ocean currents, which is/are true? Choose all that apply.

Deep-ocean currents contain water with high oxygen concentrations. Deep-ocean currents transport a volume of water equal to that of 100 Amazon-size rivers. Deep-ocean circulation is referred to as thermohaline flow. Deep-ocean currents are initiated near Antarctica and in the North Atlantic Ocean, where cold, dense water sinks. Deep-ocean currents are important regulators of global climate.

Which of the following are western boundary currents? Check all that apply.

East Australia Current Kuroshio Current Brazil Current

Which of the following statements are true regarding surface ocean currents? Check all that apply.

Gyres in the Southern Hemisphere rotate counterclockwise. Cold currents flow at high latitudes or from higher latitudes toward the equator.

Of the following conditions, which is/are related to strong El Nino events? Choose all that apply.

Higher sea levels in the eastern Pacific Ocean associated with warmer water Increased abundance of hurricanes in the eastern Pacific Ocean Increase in sea surface temperatures and destruction of coral reefs in the eastern Pacific Ocean

Of the following currents, which ones are parts of the South Atlantic Subtropical Gyre? Choose all that apply.

West Wind Drift Benguela Current Brazil Current South Equatorial Current

Which of the following best describes the profile of a thermocline that would be found in a coastal region where downwelling is taking place?

the thermocline is deeper at the coast and shallower offshore

Deep ocean current movement is also known as

thermohaline flow

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

80

The theoretical movement of surface water due to Ekman transport in the Northern Hemisphere is about

90 degrees to the right of wind direction

Of the following surface currents, which one(s) flow generally from west to east?

Equatorial Counter Current West Wind Drift North Pacific Current

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

The West Wind Drift is a part of which of the following subtropical gyres? Choose all that apply.

Indian Ocean Subtropical Gyre South Atlantic Subtropical Gyre South Pacific Subtropical Gyre

Of the following gyres, which one(s) flow in a counterclockwise direction?

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

In which of the following regions of the ocean would you expect to have a water column with the steepest pycnocline (i.e. the largest change in density between surface and deep)?

Low latitudes in summer

Which of the following occur when the Earth enters the El Nino phase of ENSO? Check all that apply.

The northeast and southeast trade winds reduce their intensity (aka ¨slacken¨) Cool surface water in the eastern Pacific is replaced by warmer water from the western Pacific

Downwelling can result from

converging surface currents

Part complete Which of the following process will increase the density of seawater? Check all that apply.

decreasing the temperature increasing the salinity evaporation

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

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

Which process causes downwelling off the coast of Antarctica?

ice formation

An indirect method of measuring ocean currents is the use of

radar altimeters

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

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. 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. Ekman transport can result in both upwelling and downwelling.

Which of the following is true about Ekman transport in the oceans? Check all that apply.

The net movement of water in the wind-driven layer is shifted 90º to the left of the wind direction in the Southern Hemisphere It is a result of the wind-driven circulation being deflected by the Coriolis effect

Of the following statements about subtropical gyres, which is/are true? Choose all that apply.

There are four main surface currents in each subtropical gyre. The western boundary current of all subtropical gyres is intensified (it is fast, narrow, and deep). Globally, there are five subtropical gyres. The centers of all subtropical gyres are associated with high atmospheric pressure. The rotation of each subtropical gyre causes a "hill" of water to pile up within it.