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What is El Nino and La Nina
El Nino and La Nina
El Niño and La Niña are opposite phases of a recurring climate pattern called the El Niño-Southern Oscillation (ENSO) cycle, which disrupts the wind and rainfall patterns across the tropics. This cycle impacts sea surface temperatures in the equatorial Pacific Ocean, having a domino effect on weather patterns worldwide.
- El Niño:
- Means “the little boy” in Spanish, possibly referencing the Christ child as El Niño events often peak around December.
- Represents the warm phase of ENSO.
- Characterized by warmer than average sea surface temperatures in the eastern and central equatorial Pacific.
- La Niña:
- Means “the little girl” in Spanish, as a counterpart to El Niño.
- Represents the cool phase of ENSO.
- Characterized by cooler than average sea surface temperatures in the eastern and central equatorial Pacific.
El Niño and La Niña events typically last 9 to 12 months but can persist for years. They occur every 2 to 7 years on average, although they are irregular and unpredictable. These fluctuations influence weather patterns globally, affecting precipitation, wildfires, ecosystems, and even economies.
El Niño and La Niña FAQ
Here are some frequently asked questions about El Niño and La Niña:
What causes El Niño and La Niña?
El Niño and La Niña arise from interactions between the Pacific Ocean’s surface and the atmosphere. Warm or cool ocean temperatures influence the atmosphere, which in turn affects the ocean temperatures, creating a cycle that flips between warm (El Niño) and cool (La Niña) conditions every 3-4 years on average.
How often do they occur?
El Niño and La Niña occur on average every 3-7 years, but the interval between events can vary considerably. The historical record shows events ranging from 2 to 7 years apart.
How long do they last?
El Niño and La Niña episodes typically last 9-12 months. They tend to develop in spring (March-June), peak in winter (November-February), and weaken in spring/early summer (March-June). El Niño events rarely last longer than a year, while La Niña events can persist for two years or more.
Does El Niño always precede La Niña?
Not always, but it’s common. A strong El Niño often leads to a La Niña the following year. This is because the strong warming in the eastern Pacific during El Niño disrupts the deep ocean circulation, which takes time to recover, leading to cooler than average temperatures in the following year (La Niña).
What are the impacts of El Niño and La Niña?
El Niño and La Niña have significant impacts on global weather patterns, affecting precipitation, drought, floods, wildfires, and even crop yields in various regions. You can find more specific information about the impacts on different parts of the world by searching for “[El Niño impacts + region name]” or “[La Niña impacts + region name]”.
Where can I find more information?
The National Oceanic and Atmospheric Administration (NOAA) has a comprehensive El Niño website with a dedicated FAQ section: NOAA El Nino FAQ
Climate.gov also has a helpful page on El Niño and La Niña: El Nino and La Nina: Frequently asked questions
