Oceanography Exam #3 Chapter 6

Ekman Transport

. Coastal winds can cause upwelling or downwelling due to...

Subtropical Convergence of water in the middle of the gyre

. Ekman transport deflects surface water to the right in the Northern Hemisphere, so a clockwise rotation develops within an ocean basin and produces the...

more than just the wind belts of the world

. In reality, ocean surface currents are driven by

downwell

...is the movement of warm, nutrient-depleted, and oxygen-depleted water from the ocean surface downward.

West ward by the north and south equatorial current and piles up water on the western side of an ocean basin near the equator

A large volume of water is driven...

low

Areas of downwelling have ... productivity because surface water in not being replenished with nutrients

they turn because of the land mass

As equatorial current reach the western portion of the ocean basin,

energy

As the surface layer moves, other layers beneath it are set in motion, thus passing the... of the wind down through the water column.

solar radiation is the ultimate energy source for creating these ocean currents.

Because wind belts generate the ocean's surface currents,

in an easterly direction across the ocean basins

Between 30° and 60° latitude the prevailing westerlies direct ocean surface water...

of North and South America, Africa, and Eurasia

Bounded the irregular shape of the continents

Eastern Boundary Current

California Current

Marine

Coastal upwelling along California is characterized by high concentration of nutrients, resulting in high productivity and rich ... life.

cool

Coastal upwelling offshore of San Francisco creates low water temperature that results in much ...weather and fog in the summer.

low water vapor content.

Cold ocean currents cool the nearby air, which is more likely to have...

dry

Continental margins that have cool ocean currents offshore typically have ... climates

dynamic topography maps, and Doppler flow meters

Corresponding pressure gradient, radar/satellite altimeters to produce...

A large volume of water is driven west ward by the north and south equatorial current and piles up water on the western side of an ocean basin near the equator

Creating a higher sea level

downwelling

Current convergence occurs when surface waters move towards each other causing the water to stack-up and no place to go but, slowly sink in a process called...

can be at the ocean's surface or deep below.

Currents

Coastal Upwelling

Deep ocean waters rise up to replace water moving away from the shore in a process called

accounts for the thorough mixing of the deep masses of ocean water.

Density-driven circulation

Vertically

Density-driven circulation moves water

floating devices

Direct methods of ocean currents are ... that are can be tracked over time or fixed devices

creates areas of high productivity that are some of the most prolific fishing grounds in the world.

Divergent current

oxygen

Downwelling is associated with lower amounts of surface productivity but carries necessary dissolved ... to those organisms living on the deep-sea floor.

wind

Due to the Ekman Spiral phenomenon, it is in direction 90° to right and 90° to the left of the ... direction in the Northern Hemisphere and Southern Hemisphere.

subsurface water movement.

Dynamic topography maps, and Doppler flow meters to determine...

4

Each subtropical gyre is composed of... main currents that flow progressively into one another

in speed and shifts to the right

Each successive layer of water decreases

cold water from the poles southward along the eastern side of an ocean basin.

Eastern boundary currents carry...

motion by wind blowing across its surface.

Ekman Sprial assumes that a uniform column of water is set in

describes the speed and direction of flow of surface waters at various depth

Ekman sprial

by wind

Ekman the net transport of surface water set in motion

is the movement of deeper nutrient-rich water onto the surface water as a result of divergent of surface currents along the equator

Equatorial Upwelling

along the equator in all ocean basins

Equatorial currents are westward-flowing current that travel

are huge circular-moving current systems that are driven by the major wind belts of the world and dominate the surface of the ocean within an ocean basin.

Gyres

heat

Gyres exist to balance the Earth's heat budget by redistributing ....absorbed by the ocean from Solar Radiation in the lower latitudes, which is transported to the higher latitudes.

the surface currents would follow the major wind belts of the world.

If there were no continents on Earth,

trade winds

In each hemisphere, a current would flow between 0° and 30° latitude as a result

Northern Boundary Currents

In the Northern Hemisphere these surface currents comprise the northern part of subtropical gyres...

move in a direction 45°to the right of the wind direction

In the Northern Hemisphere, the Coriolis Effect causes surface water in contact with the wind to

Southern Boundary Currents

In the Southern Hemisphere, they comprise the southern part of subtropical gyres

45°to the left of the wind direction.

In the Southern Hemisphere, where Coriolis curvature is to the left, the surface layer moves

of water density

Indirect methods consist of determining the internal distribution

masses of ocean water that flow from one place to another.

Ocean Currents

Velocity and direction

Ocean current measurements consist of measurements of... for surface and subsurface current flow

wind-driven or density driven.

Ocean currents are either...

adjoining landmasses.

Ocean surface currents influence the climate of the

2

Only about ...% of the wind's energy is transferred to the ocean surface, so a 50-knot wind will create a 1-knot ocean current.

Algae

Starting with an abundance of microscopic ..., the base of the food chain, supports incredible numbers of larger marine life like fish and whales.

occur in the ocean's surface waters

Surface Currents

directly or indirectly

Surface and subsurface currents can be measured

10

Surface currents affect about ...% of the world's ocean water.

friction between the ocean and the wind that blows across its surface.

Surface currents develop from...

1 kilometer

Surface currents occur within and above the pycnocline to a depth of

Surface

The ... water moves as a thin layer on top of deeper layers of water

from the equator as western boundary currents

The Coriolis Effect deflects these currents away...

gravity

The Coriolis effect opposes,

Equatorial Counter Currents

The bulge of water piled up in the in the western side of the ocean basin flows down hill under the influence of gravity , creating...

Subtropical Gyres

The center of each of Earth's five major gyres coincides with the subtropics are called

30

The center of each of Earth's five major gyres coincides with the subtropics at about ... °north and south latitude.

continents

The distribution of... on Earth influences the nature and direction of flow of surface currents in each ocean basin

2 meters high

The pile of surface water within all subtropical gyres rise as much as

western

The pile of water formed within a rotating gyre is closer to the... boundary than the geographic center of the gyre

cold

The presence of a ... current off the coast of California is part of the reason the climate there is so arid.

warm ocean current, summer

The presence of a ... off the East Coast of the United States helps explain why the area experiences such high humidity, especially during the ... months

is to transport heat from lower latitudes resulting from an excess of solar input to cooler, higher latitudes where there is a deficit of solar heating

The purpose of a gyres

in the Atlantic ocean basin

The trade winds and westerlies create a circular current

Cool (eastern boundary current) and warm (western boundary current)

The two ocean currents that affect the coast of North America are the

Gulf Stream

The western boundary current, ... , is a warm ocean current that affects England's climate.

Prevailing Westerlies

The wind energy that drives this ocean surface ocean current comes from...

the western side of an ocean basin land mass

These currents carry the warm water of the equator along

gravity

These hill of surface water in the Subtropical Convergence tends to flow downhill in response to

productivity

This cold, nutrient rich water creates an area of high ... of marine life.

is the upward vertical movement of cold, nutrient-rich, and oxygen-rich water from beneath the pycnocline toward the ocean surface

Upwelling

moisture

Warm air holds large amounts of water vapor, increasing the ... of the atmosphere

warm the nearby air.

Warm ocean currents...

is the different in the currents

Western Intensification

warm

Western boundary currents transport... water from the equator toward the poles;

Eastern Boundary

When currents flow back across the ocean basin, the Effect and continent barriers turn the them towards the equator creating the...

very little precipitation

When the cool, dry air travels over a continent it results in

Precipitation Continental margins (warm currents offshore typically have a humid climate.)

When warm, moist air travels over a continent it releases its water vapor in the form of

horizontally

Wind driven currents move water...

away

Winds blowing from the north, parallel to the west coast of a continent in the Northern Hemisphere, cause the coastal waters to flow ... from the shoreline.

towards

Winds blowing from the south, parallel to the west coast of a continent in the Northern Hemisphere, cause the waters offshore to flow ... the shoreline

1. major wind belts of the world, 2. gravity 3. seasonal changes the Coriolis Effect 4. the distribution of continents 5. Seasonal Change 6. geometry the of each ocean basins.

Worldwide, the pattern of ocean surface currents is affected by

water to pile up in the center of the subtropical convergence

a clockwise rotation develops within an ocean basin and produces the Subtropical Convergence of water in the middle of the gyre, causing

prevailing winds

a second would flow between 30°and 60°latitude as a result of the

polar easterlies

a third would flow between 60°and 90°latitude as a result of the

Equatorial currents

caused by the trade winds

Some surface waters become high in density, through low temperatures and/or high salinity and sink beneath the surface.

deep currents

when Coriolis effect opposes gravity

deflecting the water to the right in a curved path back into the hill again

low primary production

downwelling downwelling is associated with low primary production

western boundary current

it carries warm water poleward from the equator

is up to 15 time faster, 20 times narrower and 5 time deeper than the California Current

the Kuroshio Current

Western Boundary Current

the Kuroshio Current is known as

cold water from the poles toward the equator.

the eastern boundary currents transport...

Eastern

the western boundary currents of the subtropical gyres are faster, narrower, and deeper than their ... boundary current counterparts.

Example: Blow gently and steadily across a cup of coffee.

wind's energy transferred example