OCEAN CURRENTS:

CURRENT:

Continuous and directed

movement of ocean water

TWO TYPES:

Surface Currents

Deep Water Currents

SURFACE CURRENTS:

10% of water in ocean

The upper 400m of the ocean

DEEP WATER CURRENTS:

90% of water in ocean

Waters move around the

ocean basins by density

differences

Density differences a function

of different temperatures and

salinity

TWO TYPES OF FORCES:

Primary Forces: Start the water moving:Solar Heating

Winds

Gravity

Coriolis Effect

Secondary Forces: Influence where the current goes

SOLAR HEATING:

Causes water to expand

Water is about 8 cm higher

than middle latitudes, thus

water wants to flow down

slope

WINDS:

Winds blowing on surface of

the ocean push the water

Water piles up in the direction

the wind is blowing

GRAVITY

Will pull water “down the hill”

when water mounds up

CORIOLIS EFFECT:

An inertial effect due to the

spinning of the earthWhen going towards pole

you are coming from an

area that is moving faster,

thus the deflection with the

direction of the Earth’s

rotation

When going to the equator,

the deflection goes against

the spin of the Earth, due to

the spin of the Earth

GYRES:

The effect of winds and

Coriolis effect results in

circular flows of water made

of several currents

EKMAN TRANSPORT:

Surface water is blown away by winds, dragging the water beneath it

The deflection due to Coriolis Effect creates a spiral pattern and a net current to the right or left of wind

Results in upwelling

UPWELLING:

Nutrient rich water from the

deeper parts of the ocean

rises to the surface to replace

the water blown away

Animation:

DEEP WATER CIRCULATION:

Occur where the temperature

is cold and relatively high in

salinity

Thermohaline Circulation

Thermo = heat, haline = salt

EARTH CONVEYOR BELT

Salt rich, warm water is blown

north by the Gulf Stream, where

is cools and sinks

This provides heat to the polar

regions and nutrients

everywhere

Possibly disrupted by global

warming

LOCAL CURRENTS:

formed by a combination of

tides, winds, waves, and

rivers/streams

Longshore currents and rip

currents

LONGSHORE CURRENTS:

When waves strike the

shoreline at an oblique angle,

causing resultant waves to

move parallel with the

shoreline

RIP CURRENTS:

Formed when waves push the

water in front of it sideways

till it can find a path out to sea