[Rusty Woods]

What causes an El Nino weather pattern?

[Rusty Woods]

What causes an el nino weather pattern

[Rusty Woods]

For science
What causes an El Nino weather pattern?

[jmjoseph]

Average circulation in the south Pacific OceanEl Niño-Southern Oscillation (ENSO; commonly referred to as simply El Niño) is a global coupled ocean-atmosphere phenomenon. The Pacific ocean signatures, El Niño and La Niña are important temperature fluctuations in surface waters of the tropical Eastern Pacific Ocean. The name El Niño, from the Spanish for "the little boy", refers to the Christ child, because the phenomenon is usually noticed around Christmas time in the Pacific Ocean off the west coast of South America.[1] La Niña, similarly, means "the little girl". These effects were first described in 1923 by Sir Gilbert Thomas Walker from whom the Walker circulation, an important aspect of the Pacific ENSO phenomenon, takes its name. The atmospheric signature, the Southern Oscillation (SO) reflects the monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin, Australia. The most recent occurrence of El Niño started in September 2006[2] and lasted until early 2007.[3] From June 2007 on, data indicated a weak La Niña event, strengthening in early 2008 and weakening in late 2008, with a forecast return to neutral conditions in 2009.

ENSO is associated with floods, droughts, and other disturbances in a range of locations around the world. These effects, and the irregularity of the ENSO phenomenon, makes predicting it of high interest. Significant advances in the predictability of ENSO were contributed by Stephen Zebiak and Mark Cane.[4] ENSO is the most prominent known source of inter-annual variability in weather and climate around the world (about 3 to 8 years), though not all areas are affected. ENSO has signatures in the Pacific, Atlantic and Indian Oceans.

During major warm events, El Niño warming extends over much of the tropical Pacific and becomes clearly linked to the intensity of the Southern Oscillation. While ENSO effects are basically in phase between the Pacific and Indian Oceans, ENSO effects in the Atlantic Ocean lag behind those in the Pacific by 12 to 18 months. It effects areas such as Australia. Many of the countries most affected by ENSO are developing countries that are largely dependent upon their agricultural and fishery sectors for food supply, employment, and foreign exchange.

This came from Wikipedia.

[anvesh84]

El Nino, an abnormal warming of surface ocean waters in the eastern tropical Pacific, is one part of what's called the Southern Oscillation. The Southern Oscillation is the see-saw pattern of reversing surface air pressure between the eastern and western tropical Pacific; when the surface pressure is high in the eastern tropical Pacific it is low in the western tropical Pacific, and vice-versa. Because the ocean warming and pressure reversals are, for the most part, simultaneous, scientists call this phenomenon the El Nino/Southern Oscillation or ENSO for short. South American fisherman have given this phenomenon the name El Nino, which is Spanish for "The Christ Child," because it comes about the time of the celebration of the birth of the Christ Child-Christmas. Scientists do not really understand how El Nino forms. It is believed that El Nino may have contributed to the 1993 Mississippi and 1995 California floods, drought conditions in South America, Africa and Australia. It is also believed that El Nino contributed to the lack of serious storms such as hurricanes in the North Atlantic which spared states like Florida from serious storm related damage.

Unfortunately not all El Nino's are the same nor does the atmosphere always react in the same way from one El Nino to another. This is why NASA's Earth scientists continue to take part in international efforts to understand El Nino events. Hopefully one day scientists will be able to provide sufficient warning so that we can be better prepared to deal with the damages and changes that El Nino causes in the weather.