1. El Niño and La Niña

2. ENSO describes a combined oceanic-atmospheric disturbance
El Niño
(Spanish for “the Child” in reference to baby Jesus)
warm surface current in equatorial eastern Pacific that occurs periodically around Christmastime.
The average period length is 5 years.
occurs for only seven to nine months.
fluctuates between warmer-than-average
Southern Oscillation = change in atmospheric pressure over Pacific Ocean accompanying El Niño
Sir Gilbert Walker and colleagues extended the early studies and determined.
ENSO describes a combined oceanic-atmospheric disturbance

3. La Niña:
It is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño or "anti-El Niño“
During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C.
In the United States, an episode of La Niña is defined as a period of at least 5 months of La Niña conditions.
The name La Niña originates from Spanish, meaning "the girl",
colder-than-average conditions

4. Normal conditions in the Pacific Ocean

5. El Niño conditions (ENSO warm phase)

6. La Niña conditions (ENSO cool phase; opposite of El Niño)

7. Typical January to March Weather Anomalies
El Nino
La Nina

8. Sea Surface Temperatures
Equatorial cold tongue is weaker than average or absent during El Niño, resulting in positive SST anomalies

9. El Niño recurrence interval
Typical recurrence interval for El Niños = 2-7 years
Pacific has alternated between El Niño and La Niña events since 1965

10. Effects of severe El Niños

11. 1. Worldwide Bleaching of Coral reef

12. 2. Impact over Marine life

13. El Niño and La Niña impacts ocean productivity
Normal Conditions and La Nina = more productive
Nutrients
                             
                             
El Nino Conditions = less productive
During an El Niño event, the southeast trade winds weaken and so does the amount upwelling in the eastern Pacific. The deeper thermocline means that any upwelling that does occur is unable to tap into the rich nutrients found in deeper waters. Consequently, warm nutrient-poor water predominates the region and a decrease in the fish population is observed.
During non-El Niño years, the southeast trade winds, drag surface water westward away from shore. As surface water moves away, upwelling brings up colder waters from depths of meters or more. This deep sea water is rich in nutrients which can sustain large fish populations.

14. 3. Flood

15. 4. Drought

16. 5. Coastal Erosion

17. 6. Tropical cyclone

18. 7. Forest Fire

19. 8. Birds life

20. 9. El Niño an Jet Stream Jet stream (~12km) shifts North
Normal/La Nina
El Nino
Jet stream (~12km) shifts North
during El Nino years (thin arrows)
More storms develop in the Gulf of Mexico, bringing heavy rains to much of the southern United States during El Nino.
Jetstream is at ~12km height.

21. Global La Niña Impacts

22. Typical Global La Niña Impacts
Region
Period
Impact
Indonesia
Life of event
Wetter
Northeast Brazil
March-May
Central America /Mexico
May-October
West Coast
South America
Drier
Central South America
June-December
Southeast Africa
December-February