Ocean circulation ch 7

A rapid decrease in water temperature occurs within the ______ layer in the water column.

thermocline

The mixing layer is often thicker in the open ocean than in protected coastal waters because ______.

in the open ocean, there is more turbulence of water caused by waves and wind

Which of the following statements are true regarding a seasonal thermocline and a "permanent thermocline"?

A "permanent thermocline" is not influenced by surface-water temperatures.

A "permanent thermocline" is generally deeper than a seasonal thermocline.

A seasonal thermocline often occurs at mid-latitudes.

Which of the following statements are true regarding how seasonal thermoclines may change during the year?

Seasonal thermoclines in the mid-latitudes may form in the summer and disappear in the winter.

A steep seasonal thermocline can develop above the permanent thermocline during the summer as surface temperatures rise and winds decrease.

In the ocean, the greatest amount of heat from incoming solar radiation would transfer to ______.

the top 10 cm of the surface

mixed layer

A surface layer tens to a few hundred meters thick

thermocline

Extends from below a few hundred meters to a depth of about 1000 m

high latitudes

There is no permanent thermocline; however, weak seasonal thermoclines can develop in the summer

mid latitudes

Significant seasonal variation occurs here in the temperature-versus-depth profile

low latitudes

There is no development of a seasonal thermocline, and the three temperature layers are quite stable.

Which of the following influence the depth of the mixing layer?

The amount of turbulence caused by waves

The amount of turbulence caused by wind

At low latitudes, surface temperatures are warm and constant throughout the year, so no ______ thermocline develops. At high latitudes (above 60°), there is no ______ thermocline.

seasonal; permanent

In what season would the seasonal thermocline occur as shown in the graph? And why would it occur?

The surface temperatures increase.

It would occur in summer.

The halocline is the marked change in ______ with depth.

salinity

As seawater temperature decreases, the density of seawater ______.

increases

A shallow mixed layer with relatively constant density overlies the pycnocline layer, where density ______ rapidly with depth.

increases

stable water column

A column of water where the density increases with depth

unstable water column

A column of water that consists of higher-density water on top of lower-density water

marked change in salinity with depth in the ocean

halocline

Seawater density is ______ to temperature and ______ to salinity.

inversely proportional; directly proportional

Thermohaline circulation is a motion, or flow, of ocean water caused by variations in density due to differences in ______ and ______.

temperature and salinity

If the density of water increases with depth, the water column from the surface to that depth is ______. If there is higher-density water on top of lower-density water, the water column is ______.

stable; unstable

Areas of thermohaline circulation where water sinks are called _______ zones and areas of rising waters are called ________ zones.

downwelling; upwelling

When surface waters are driven together by the wind or up against a coast, a surface-water _______ is formed, but when the wind blows surface waters away from an area or a coast, a surface-water _______ occurs and water upwells from below.

convergence; divergence

Layers of ocean water are associated with ______.

depth zones: surface, intermediate, deep, and bottom

north atlantic deep water

This water sinks and moves southward from the Norwegian Sea along the east side of the Atlantic.

antarctic bottom water

This water mass is the densest water in the ocean and sinks to the ocean floor. It moves slowly northward through the deep South Atlantic ocean basins west of the Mid-Atlantic Ridge

Mediterranean intermediate water

This water possesses an intermediate water density and flows out of the Strait of Gibraltar for about 1500 miles before being lost through modification and mixing

The motion, or flow, of water in the ocean resulting from variations in water density is called ______.

thermohaline circulation

Which of the following characteristics contributes to the Pacific Ocean having less dramatic layering than the Atlantic Ocean?

There is no large source of deep water in the Pacific Ocean that compares to that found in the North Atlantic.

the Pacific Ocean's size is much greater than the Atlantic Ocean

The Pacific Ocean has relatively small areas of surface convergence, causing the sinking water to lose its identity rapidly

downwelling zone

known for containing oxygen-rich water

upwelling zone

known for containing low oxygen-content, nutrient-rich water

Ocean ______ is(are) influenced by wind, atmospheric circulation, and Earth's rotation.

surface currents

Each layer of the ocean receives its characteristic salinity, temperature, and density ______.

at the surface

______ water moves slowly ______ through the South Atlantic ocean basins west of the Mid-Atlantic Ridge, but the ______ water sinks and moves ______ along the east side of the Atlantic.

Antarctic bottom; north; North Atlantic deep; south

he layering of the Atlantic Ocean is quite dramatic compared to the layering of the Pacific because ______.

the Atlantic Ocean has a smaller volume of water

the Atlantic is a narrow, confined ocean with a great north-south extent

Which of the following factors drive ocean surface currents?

Wind

Internal inertia

Coriolis effect

Over the depth of an Ekman spiral, the water moves 90° to the right in the _________ Hemisphere and 90° to the left in the _______ Hemisphere.

northern; southern

When surface winds blow, water movement is initiated; however, deep layers of water move more slowly because of low-friction coupling in the water resulting in a(n) ______.

ekman spiral

Gyres rotate in ______ directions in the Northern and Southern Hemispheres because they are under the influence of the westerlies.

opposite

Large, circular motion, wind-driven current systems are known as ______.

gyres

The surface current acted upon by the Coriolis effect is deflected to the ______ of the driving wind direction in the Northern Hemisphere and to the ______ in the Southern Hemisphere.

right; left

Currents flow ______ when a large volume of water flows through a narrow gap.

faster

Western intensification creates a more steeply sloping surface over a shorter distance on the ______ side of the mound of water created by the Ekman transport and a more gently sloping sea surface over a longer distance on the ______ side of the mound.

western; eastern

Why do gyres rotate in opposite directions in the two hemispheres?

The major trade winds drive surface currents from east to west on either side of the equator.

As a result of western intensification, geostrophic currents flowing on the western side of the gyre tend to be much ______ than on the eastern side.

faster, deeper, and narrower

When the cross-sectional area of a current expands, the current ______.

slows down because flow is distributed over the width and depth of the current

Resulting from western intensification, _______ currents flowing on the western side of the gyre tend to be much faster, deeper, and narrower than on the eastern side.

geostrophic

Western intensification of currents traveling from low to high latitudes is related to the ______.

friction between landmasses and ocean water currents

changing strength and direction of the east-west wind field (trade winds and westerlies) with latitude

The ______ Current is faster and narrower than the ______ Current.

Kuroshio; California

______ waters are more closely associated with downwelling, whereas _____ waters are more closely associated with upwelling.

Convergent; divergent

A permanent zone of ______ occurs off the west coast of South America where the upwelling creates a productive fishery.

divergence

The Great Ocean Conveyor Belt describes ______.

the mass movement of warm and cold water in a vertical circulation pattern in the ocean

The major zones of surface water convergence occur where?

30° to 40° N and S

The equator

50° N and S

In regard to the Pacific Decadal Oscillation, cold and wet conditions are associated with a(n) ______ current flow, and warm and dry conditions are associated with a(n) ______ flow.

southern; northern

Which of the following is an example of a permanent zone of divergence?

Coastal areas where continuous trade winds move the surface waters away from the continent

Off the west coast of North America, ______ winter winds lead to downwelling, and ______ summer winds cause upwelling.

southerly; northerly

The Great Ocean Conveyor Belt involves a thermohaline circulation pattern whereby ______ surface water simultaneously moves above ______ deep water, sometimes in opposite directions.

warm; cold

The Pacific Decadal Oscillation is a current shift associated with changes in _______.

winds

precipitation

water temperature

atmospheric pressure