El Nino/ ENSO And La Nina Flashcards
What is El Niño linked to?
Linked to similar periodic changes in normal atmospheric pressure and wind patterns- The Southern Oscillation
What does El Niño refer to?
Episodes when normal surface ocean current circulation patterns are disrupted
What are The Southern Oscillation and El Niño now referred to?
ENSO
What are the normal atmospheric conditions in the Pacific Ocean?
- Trade winds blow from East to West
- Surface ocean currents follow the trade winds and blow from East to West
- Warm water collects in the Western Pacific
- Sea level is higher in the Western Pacific
What happens to the trade winds during ENSO conditions?
Winds become weaker due to changes in atmospheric patterns, also weakens the equatorial currents in ocean
What are some of the results of ENSO?
- Countercurrent strengthens and brings warm water to normally cool Eastern pacific. Cause massive floods and heavy rainfall.
- Western Pacific becomes cool& dry. Droughts occur in Australia and southeastern Asia
When does ENSO usually occur?
Occurs in nov/dec- April
What happens to hurricane development as a result of ENSO?
May be disrupted due to shearing winds. Total # and overall strength may decrease
What conditions occur during La Niña?
Occurs when trade winds in Pacific become stronger, equatorial currents increase as well.
More warm water flows to western Pacific Ocean
What are the results of La Niña?
Normally cool dry Eastern Pacific becomes even drier. Western Pacific becomes more wet and warm. Flooding occurs in Australia and Eastern Asia
What happens to hurricanes as a result of La Niña?
They may increase due to strong easterly winds.
T/F oceanographers consider La Niña to be part of the ENSO cycle
True
What part of the ENSO cycle is La Niña? El Niño?
La Niña cool ENSO phase
El Niño warm ENSO phase
