1. Ocean Currents, and El Nino

2. The Spherical Earth
Latitude – measures distance North or South of the equator
Longitude – measures distance East or West from the Prime Meridian
Temperate Zones – sun’s rays are never perpendicular
Polar Zones – 24 hour sunlight in summer and 24 hours darkness in winter
Tropical Zones – sun’s rays are perpendicular to the Earth’s surface for the entire year

3. Wind patterns and the rotating Earth
Without the Earth’s rotation:
Air moving from the Equator would cool by 30 degrees latitude and fall to return to the equator or move to the poles
Air travelling from the poles would warm up by 60 degrees latitude and rise up to return to the poles

4. The Coriolis effect is the influence of the Earth’s rotation on air or any object moving on the Earth’s surface
In the Northern hemisphere, this causes wind to blow to the right (clockwise)
In the Southern hemisphere, this causes wind to blow to the left (counter-clockwise)

5. The jet stream are ribbons of extremely fast moving air near the top of the troposphere
It is caused by contact between the cold and warm air and is found at the boundaries between the polar and temperate zones and the temperate and tropical zones
Weather north of the jet stream is cold, weather below it is warm

6. Ocean Currents
Surface currents are caused by wind and carry warm and cold water all over the globe

7. The ability to carry heat and maintain the temperature over long distances is due to the high heat capacity of water
The Coriolis effect causes the ocean currents to flow clockwise in the North and counter-clockwise in the South

8. The currents in oceans appear to move in a circular pattern called gyres. The right side of gyres has cool water and the left side holds warm water (both affect weather on the land).

9. Deep Ocean Currents are not caused by wind
Deep Ocean Currents are not caused by wind. Instead the currents are caused by cold water sinking and warm water rising, as well as the fact the salt water is more dense than fresh water.
A combination of deep and surface currents caused the “great ocean conveyor belt” which moves water around the world.

10. El Nino
Wind blows west from Peru to Australia. This causes an upwelling of cold, nutrient rich water near Peru which also moves west to Australia causing rain there.
During an El Nino year, a warming of these cool waters occurs because the trade winds reverse and blow from Australia to Peru.

12. Hot/Cold Currents
Warm Currents: Gulf Stream, Alaskan, Kuroshio, Brazil, South Equatorial, North Equatorial, East Australian, North Atlantic, North Equatorial, East Australian
Cold Currents: West Wind Drift, Humboldt, California, Canary, Bengula, West Australian, Labrador, Gulf Stream,

13. Ocean Currents There are two types of ocean currents:
Surface Currents: These are wind driven, they occur in about 10% of the ocean water, but cover the entire ocean surface.
Thermohaline Currents: (thermo = heat and haline = salt) These are density driven currents. They occur deeper in the ocean in about 90% of the ocean water.

14. Surface Currents Surface currents are mostly horizontal currents.
These currents follow the pattern of the wind.
They occur from the surface down to a few hundred meters.
Generally travel clockwise in the northern hemisphere and counter clockwise in the southern hemisphere.

15. Deep
Thermohaline currents are driven by density and temperature changes in the water.
These currents are also known as the “ocean’s conveyor belt”
They flow under the surface of the ocean and move significant amounts of ocean water vertically.

16. Why Are Surface important?
Surface currents for the general “mixing” of the worlds oceans and waters
Surface Currents will move nutrients from more productive areas to less productive areas of the worlds oceans.
They are also important in migration and the movement of many less active (or passive) organisms.

17. Why Thermohaline (Deep) Currents important?
These create “upwells”
Upwells are: the movement of water from the much deeper water too shallow waters through out the Ocean
This makes so all ocean nutrients don’t end up settling on the bottom of the ocean.
This mixing makes it so surface organisms can sustain life.