Science Ocean Current and Climate

What 3 things create Surface Currents?

1. Global wind patterns, 2. rotation of the Earth, 3. shape of Ocean Basins (when a surface current collides with land it changes the direction of the current )

2 types of winds that drive Surface Currents

1. Westerlies 2. Trade Winds

How many main ocean basins are there?

5

Current

A large stream of moving water that flows through oceans and carry water great distances

Gyres

A loop created by Surface Ocean Currents

What causes the difference in density of the water in a deep current?

As warm water surface currents move from the equator to the poles, the water cools off. As Ice forms near the poles, the salinity of the water increases from the salt left behind during freezing. As its temperature decreases and its salinity increases, the water becomes denser and sinks. Then the cold water flows back along the ocean floor as a deep current.

Deep Currents

Cause cold waters at the bottom of the ocean to move slowly across the ocean floor. They are caused by difference in density, NOT surface winds.

In what shaped pattern do most large surface currents move?

Circular

Surface Currents on the West Coast of the US tend to be?

Cold

If you are looking at the Earth from a position above the North Pole, in which direction is the Earth rotating?

Counter-Clockwise

Surface Current

Currents that are powered by wind and affect water to a depth of several hundred meters. They can flow for thousands of kilometers

Which direction do the Westerlies blow?

East to West (40-50 degrees latitude)

Density Current

Is a kind of deep current. It is a mass of dense seawater that sinks beneath less dense seawater due to changes in temperature and salinity. Gravity causes more dense seawater to sink below less dense seawater. These currents move very slowly.

El Nino

Is an abnormal climate event that happens when an unusual pattern of winds forms over the Western Pacific Ocean. The winds blowing cold water from the coast of Peru slow down, which causes a very large sheet of warm water to move eastward towards the South American coast. The strange conditions may last from 1-2 yrs before the normal winds and currents occur. The warm water causes upwellings to stop. This can kill the fish or cause them to to go to other areas, which hurts the fishing industry. Because of El Nino, weather patterns are shifted around the world, causing either unusual weather or more severe conditions, such as draught, flood, mudslides, hurricanes, tornadoes, colder winters and hotter summers.

Upwelling

Is the upward movement cold water from the ocean depths. As winds blow away the warm surface water, cold water rises to replace it. This cold water brings up tiny organisms and nutrients from the deep layers to the surface.

Which way do surface currents curve in the Southern Hemisphere because of the Coriolis Effect?

Left

Temperature

Measurement of the movement of energy in matter.

Where do Warm Surface Currents originate/begin?

Near the Ecuador

Where do Cold Surface Currents originate/begin?

Near the Poles

Density

Number of things in a given amount of space. D= M/ V . Density = Mass/Volume

Which way do surface currents curve in the Northern Hemisphere because of the Coriolis Effect?

Right

How do surface currents affect climate on land?

Surface Currents circulate warm and cold water around the Earth, either warming or cooling the air above it, thus affecting the climate.

Density of water is determined by what 2 things?

Temperature and Salinity

What happens when a surface current meets land?

The current changes direction

Coriolis Effect

The effect of Earth's rotation on the direction of winds and currents. As the earth rotates, the paths of the winds and currents curve in relation to Earth's surface.

Gulf Stream

The largest and most powerful surface current in the North Atlantic Ocean. caused by strong winds from the West. It is more than 300 meters deep and carries warm water from the Gulf Of Mexico to the Caribbean Sea and then Northward along the US coast near Cape Hatteras, NC.

Climate

The pattern of temperature and precipitation typical of an area over a long period of time. Currents affect climate by moving warm and cold water around the globe.

Salinity

The total amount of dissolved salts in water, usually measured in ppt (parts per thousands)

Surface Currents on the East Coast of the US tend to be?

Warm

What most affects ocean temperature in the surface zone?

Weather

Which direction do Trade Winds blow?

West to East (20 degrees latitude)

What determines whether a Surface Current is warm or cold?

Where it originates/begins.

Can Surface Currents remain unchanged in large storms?

Yes, because they are created by 3 things that do not change during storms.

Other factors in addition to wind that can influence Surface Currents?

tides, rain, evaporation, river run-off