WHAT IS El Niño ?

Some might be wondering what am talking about here..

Work of  El Niño

El Niño is the warm phase of the El Niño Southern Oscillation (commonly called ENSO) and is associated with a band of warm ocean water that develops in the the central and east-central equatorial Pacific (between approximately the International Date Line and 120°W), including off the Pacific coast of South America. El Niño Southern Oscillation refers to the cycle of warm and cold temperatures, as measured by sea surface temperature, SST, of the tropical central and eastern Pacific Ocean. El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific. The cool phase of ENSO is called "La Niña" with SST in the eastern Pacific below average and air pressures high in the eastern and low in western Pacific. The ENSO cycle, both El Niño and La Niña, causes global changes of both temperatures and rainfall. Mechanisms that cause the oscillation remain under study.
Developing countries dependent upon agriculture and fishing, particularly those bordering the Pacific Ocean, are the most affected.

A flooded street in Laguna Beach during the 1982/83 El Nino.

El Niño is defined by prolonged warming in the Pacific Ocean sea surface temperatures when compared with the average value. The U.S NOAA definition is a 3 month average warming of at least 0.5 °C (0.9 °F) in a specific area of the east-central tropical Pacific Ocean, other organizations define the term slightly differently. Typically, this anomaly happens at irregular intervals of two to seven years, and lasts nine months to two years. The average period length is five years. When this warming occurs for seven to nine months, it is classified as El Niño "conditions"; when its duration is longer, it is classified as an El Niño "episode".
The first signs of an El Niño are a weakening of the Walker circulation and strengthening of the Hadley circulation and may include

•  Rise in surface pressure over the Indian Ocean, Indonesia, and Australia
•  Fall in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean
• Trade winds in the south Pacific weaken or head east
• Warm air rises near Peru, causing rain in the northern Peruvian deserts

 El Niño's warm rush of nutrient-poor water heated by its eastward passage in the Equatorial Current, replaces the cold, nutrient-rich surface water of the Humboldt Current. When El Niño conditions last for many months, extensive ocean warming and the reduction in easterly trade winds limits upwelling of cold nutrient-rich deep water, and its economic impact to local fishing for an international market can be serious.
More generally, El Niño can affect commodity prices and the macroeconomy of different countries - and not always for the worst. It can constrain the supply of rain-driven agricultural commodities; reduce agricultural output, construction, and services activities; create food-price and generalised inflation; and may trigger social unrest in commodity-dependent poor countries that primarily rely on imported food. A University of Cambridge Working Paper shows that while Australia, Chile, Indonesia, India, Japan, New Zealand and South Africa face a short-lived fall in economic activity in response to an El Niño shock, other countries may actually benefit from an El Niño weather shock (either directly or indirectly through positive spillovers from major trading partners), for instance, Argentina, Canada, Mexico and the United States. Furthermore, most countries in the sample experience short-run inflationary pressures following an El Niño shock, while global energy and non-fuel commodity prices increase.

 Recent occurrences

Flooding in California during 1997–98 El Nino

 Since 2000, a number of El Niño events have been observed. El Niño events were observed in 2002–03, 2004–05, 2006–07 and 2009–10. A strong El Niño has not occurred since 1997–98.
The last El Niño occurred in 2009-2010 and brought drought to Australia and rains to California. The weather pattern generally occurs in cycles of two to seven years and is the warm extreme of the El Niño/Southern Oscillation (ENSO), the fluctuation in tropical Pacific Ocean temperatures. The cold phase of the oscillation is called La Niña. (Since El Niño tends to be especially strong close to Christmas, South American fishermen named the weather pattern after the Christ child Jesus.)