apes el nino + la nina

When does ENSO occur?

3-7 years

Where?

Pacific ocean under equator between Australia and South America

What are the neutral conditions in Australia and Southeast Asia before el nino and la nina?

warm and lots of rain and winds blow east to west

What are the neutral conditions in South America before el nino and la nina?

upwellings occur and it is cooler, and winds blow east to west

What is an upwelling?

When the water is cold and nutrient rich with lots of oxygen and it replaces warm waters blown away from wind

What is a benefit of an upwelling?

Aquatic species are getting more access to nutrients and it benefits local fishing businesses.

What is the balance between the colder deeper waters and warmer surface waters?

Equatorial thermocline

In normal conditions what does the thermocline do?

Tilt from east to west. Cold warm waters replace warm in the east and warm replaces cold in the west.

During el nino, what happens to the trade winds?

They weaken and reverse.

What effect does the weaken/reverse winds have on South America?

Warmer waters pool up there

What can this lead to in South America?

Flooding, landslides, and suppressed upwellings

What effect does the weaken/reverse winds have on Australia and Southeast Asia?

They receive colder and drier weather

What can this lead to in Australia and Southeast Asia?

Droughts

What do the suppressed upwellings do to South America and the thermocline?

Lack oxygen and nutrient rich water and the thermocline flattens

During la nina, what happens to the trade winds?

they are intensified

During la nina, what happens to the waters?

greater than normal movement of warm surface water to the west

What happens to the weather in Australia/SEA when the waters warm up?

Way warmer weather and higher than average rainfall

What disastrous effect can this have?

Flooding

During la nina, what happens to the South America?

they experience colder and drier weather

What disastrous effect can this have?

Droughts

What positive effect can this have?

The winds blow more water west which creates stronger upwellings

What does this do to the thermocline?

It becomes steeper