* El Niño- Southern Oscillation (ENSO) is a climate pattern that occurs across the Pacific Ocean on average every five years, but over a period which varies from three to seven years.* Is best –known for its association with floods, droughts and other weather disturbances in many regions of the world.
* El Niño is composed of an oceanic component, which is characterized bywarming of surface waters in the tropical eastern Pacific Ocean.
* Also, it’s composed of an atmospheric component, the Southern Oscillation, which is characterized by changes in surface pressure inthe tropical western Pacific Ocean.
* El Niño refers to Christ child, because periodic warming in the Pacific near South America is usually noticed around Christmas.
* In theeastern part, deeper water (which is colder than the sun-warmed surface water) gets pulled up from below to replace the water pushed west. So, the normal situation is warm water (about 30 C) in the west,cold (about 22 C) in the east.
* In El Niño, the winds pushing that water around get weaker. As a result, some of the warm water piled up in the west slumps back down to the east, and not as muchcold water gets pulled up from below. Both these tend to make the water in the eastern Pacific warmer, which is one of the hallmarks of El Niño.
* The warmer ocean then affects the winds--it makesthe winds weaker. So if the winds get weaker, then the ocean gets warmer, this is called a positive feedback, and is what makes El Niño grow.
* Is associated with warm and very wetsummers.
* It causes floods.
* Reduces the upwelling of cold.
El Niño Conditions. Warm water pool approaches South American coast. Absence of cold upwelling increases warming.
A floodRegional impacts of warm ENSO episodes
* Is characterized by cooling of surface waters in the tropical eastern Pacific Ocean, and an atmospheric component, the Southern Oscillation,...