Ocean currents

P1, p2 later

What drives ocean currents?

Wind drives surface currents

temperature and density

Coriolis effect

How does the Wind effect currents?

Pushes water across the surface

How does temperature and density effect currents?

Sinking + Rising of currents.

How does the Coriolis effect effect currents?

Currents are deflected clockwise in the N hemisphere and counterclockwise in the S Hemisphere.

The Coriolis effect

the earth moves faster at the equators than at the poles

Surface currents result from?

global wind patterns

What causes global wind patterns?

The uneven heating of earths surface

Ocean Gyres?

A system of rotating ocean currents that circulate around a central point

(warm) equatorial waters are driven

Westward by trade winds and then curved pole ward by the Coriolis effect

Ocean Gyres play and important role in

Maintaining earths heat balance, they transfer heat from tropics into the polar regions. 

Whats role does the Gulf stream have?

Earth climate, transporting a lot of heat energy

The gulf stream keeps western europe

warmer than it would be without it

If this current were to slow down what would happen?

Major implication for global climate

California current

A cold water Pacific ocean current that moves southward along the western coast of north america, from Canada to Baja. The resulting cold waters here are a prime location for the growth of kelp forests

Humboldt current

Aka Peru current, delivers cold water up the coast of south America. In Conjunction with upwellings, this creates cold water conditions near the equator. This explains why penguins can be found in the Galapagos islands. 

Gulf stream

Delivers warm water from the tropics to the norther Atlantic. Some water loops through the warm, shallow gulf of Mexico before rejoining the Gulf stream to move north. This current strongly influenced climate in both eastern U.S. and western Europe. 

Warm Surface currents

-increased rates of evaporation

-heavy rainfall on nearby coasts

-High cloud cover

-high humidity

Cold surface currents

-low evaporation

-arid, dry coastlines

-less clouds

-foggy conditions. 

Vertical Currents

Up-welling deliver cold nutrient-rich water to the surface

Where do Up-wellings occur?

Where winds force surface water away from the coastline, creating a low pressure area that pulls deep water up or where seamounts can deflect water upwards

How does the surrounding water react?

The water becomes fertilized, increasing productivity of plankton and producing strong food webs

Downwelling

The sinking of surface water

More dense water

sinks, often colder or saltier

In the north Atlantic where does the saltier surface water come from?

the equator, but then its gets cold and sinks. Which forms the north Atlantic deep water current

What does the Atlantic deep water current do?

Carries oxygen rich water to the deep atlantic

What is the global conveyor belt?

A system of slow moving currents that begins with the down-wellings of the north Atlantic deep water currents and travels through all of the oceans.

The global conveyor belt consists of

Surface, deep, and vertical currents

The Conveyor belt AKA

Thermohaline Circulation, as it is driven by density differences