Table of Contents
What is a La Niña event?
La Niña events are typically defined when SOI values are sustained above +7 and NINO3. 4 temperatures are more than −0.8 °C below average. Events that maintain index values close to these thresholds are generally classified as moderate to weak, while those that greatly exceed them are referred to as strong.
What is El Nino La Niña phenomenon?
El Niño and La Niña are a global climate phenomenon caused by cyclical shifts in the water temperature of the Pacific Ocean. They influence both temperature and rainfall. Each El Niño or La Niña event lasts between 9–12 months, and, on average, occurs every 2–7 years.
What is ENSO Upsc?
The ENSO is a recurring climatic pattern involving temperature changes in the waters of the eastern and central tropical Pacific Ocean, and changes in the patterns of upper and lower-level winds, sea level pressure, and tropical rainfall across the Pacific Basin.
How do El Niño and La Niña affect climate?
El Niño impacts weather systems around the globe, triggering predictable disruptions in temperature, rainfall and winds. La Niña is the opposite – a cooling phase of ENSO that tends to have global climate impacts opposite to those of El Niño.
What climate conditions occur during La Nina?
During a La Niña year, winter temperatures are warmer than normal in the South and cooler than normal in the North. La Niña can also lead to a more severe hurricane season. La Niña causes the jet stream to move northward and to weaken over the eastern Pacific.
How does La Nina affect weather?
During a La Nina event, the changes in Pacific Ocean temperatures affect the patterns of tropical rainfall from Indonesia to the west coast of South America. These changes in tropical rainfall patterns affect weather patterns throughout the world.
What does El Niño involve?
An El Niño condition occurs when surface water in the equatorial Pacific becomes warmer than average and east winds blow weaker than normal. During this phase of ENSO, the water is cooler than normal and the east winds are stronger. El Niños typically occur every 3 to 5 years.
What is El Niño Drishti IAS?
El Nino and the Southern Oscillation, also known as ENSO is a periodic fluctuation in sea surface temperature (El Niño) and the air pressure of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean.