El Niño–Southern Oscillation

El Niño-Southern OscillationEl NiñoENSOEl Niño Southern OscillationSouthern OscillationSouthern Oscillation IndexEl Nino Southern OscillationLa NiñaEl Nino eventsEl Niño events
El Niño–Southern Oscillation (ENSO) is an irregularly periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics.wikipedia
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El Niño

El NinoEl Nino-Southern OscillationEl Niño Southern Oscillation
The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña.
El Niño is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (between approximately the International Date Line and 120°W), including the area off the Pacific coast of South America.

La Niña

La NinaEl Niño
The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña.
La Niña is a coupled ocean-atmosphere phenomenon that is the colder counterpart of El Niño, as part of the broader El Niño–Southern Oscillation climate pattern.

Sea surface temperature

sea surface temperatureswater temperaturesocean temperature
El Niño–Southern Oscillation (ENSO) is an irregularly periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics.
Between 1985 and 1994, an extensive array of moored and drifting buoys was deployed across the equatorial Pacific Ocean designed to help monitor and predict the El Niño phenomenon.

Humboldt Current

HumboldtPeruHumboldt ocean current
Normally the northward flowing Humboldt Current brings relatively cold water from the Southern Ocean northwards along South America's west coast to the tropics, where it is enhanced by up-welling taking place along the coast of Peru.
Periodically, the upwelling that drives the system's productivity is disrupted by the El Niño-Southern Oscillation (ENSO) event, often with large social and economical impacts.

Typhoon

typhoonsWestern PacificPacific typhoon
The western side of the equatorial Pacific is characterized by warm, wet, low-pressure weather as the collected moisture is dumped in the form of typhoons and thunderstorms.

Climate variability

climate patternclimate oscillationclimate cycle
La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño Southern Oscillation climate pattern.
A prominent example is the El Niño Southern Oscillation, involving sea surface temperatures along a stretch of the equatorial Central and East Pacific Ocean and the western coast of tropical South America, but which affects climate worldwide.

Teleconnection

Transitional phases at the onset or departure of El Niño or La Niña can also be important factors on global weather by affecting teleconnections.
The most emblematic teleconnection is that linking sea-level pressure at Tahiti and Darwin, Australia, which defines the Southern Oscillation.

Gilbert Walker

Gilbert Thomas WalkerSir Gilbert WalkerSir Gilbert Thomas Walker
The two phases relate to the Walker circulation, which was discovered by Gilbert Walker during the early twentieth century.
This is now called the El Niño Southern Oscillation.

Peru

PerúRepublic of PeruPeruvian
Normally the northward flowing Humboldt Current brings relatively cold water from the Southern Ocean northwards along South America's west coast to the tropics, where it is enhanced by up-welling taking place along the coast of Peru.
The combination of tropical latitude, mountain ranges, topography variations, and two ocean currents (Humboldt and El Niño) gives Peru a large diversity of climates.

Pacific–North American teleconnection pattern

Pacific-North American teleconnection pattern
During the neutral ENSO phase, other climate anomalies/patterns such as the sign of the North Atlantic Oscillation or the Pacific–North American teleconnection pattern exert more influence.
Although the PNA pattern is a natural internal mode of climate variability, it is also strongly influenced by the El Niño-Southern Oscillation (ENSO) phenomenon.

Pacific Ocean

PacificSouth PacificWestern Pacific
This component is an oscillation in surface air pressure between the tropical eastern and the western Pacific Ocean waters.
In the tropical and subtropical Pacific, the El Niño Southern Oscillation (ENSO) affects weather conditions.

Upwelling

coastal upwellingupwelledupwell
These anomalous easterlies induce more equatorial upwelling and raise the thermocline in the east, amplifying the initial cooling by the southerlies.
Another threat to the productivity and ecosystems of upwelling regions is El Niño-Southern Oscillation (ENSO) system, or more specifically El Niño events.

Paul Julian (meteorologist)

Paul JulianPaul Rowland Julian
The Madden–Julian oscillation, or (MJO), is the largest element of the intraseasonal (30- to 90-day) variability in the tropical atmosphere, and was discovered by Roland Madden and Paul Julian of the National Center for Atmospheric Research (NCAR) in 1971.
(The El Niño–Southern Oscillation is a related phenomenon, but a standing pattern.) The ability to identify and forecast the MJO "is of considerable importance" in the ability of meteorologists to predict short-term variability in climate, and to perform long-term predictions of tropical and subtropical weather based on modeling.

Global warming

climate changeglobal climate changeanthropogenic climate change
The studies of historical data show the recent El Niño variation is most likely linked to global warming.
By itself, the climate system experiences various cycles which can last for years (such as the El Niño–Southern Oscillation) to decades or centuries.

Intertropical Convergence Zone

doldrumsITCZInter-Tropical Convergence Zone
It leads to a localized acceleration of the trade winds in the region, and can enhance thunderstorm activity when it interacts with the Intertropical Convergence Zone.
The southern ITCZ in the southeast Pacific and southern Atlantic, known as the SITCZ, occurs during the Southern Hemisphere fall between 3° and 10° south of the equator east of the 140th meridian west longitude during cool or neutral El Niño–Southern Oscillation (ENSO) patterns.

North Atlantic oscillation

NAOAtlantic oscillationNorth Atlantic
During the neutral ENSO phase, other climate anomalies/patterns such as the sign of the North Atlantic Oscillation or the Pacific–North American teleconnection pattern exert more influence.
Unlike the El Niño-Southern Oscillation phenomenon in the Pacific Ocean, the NAO is a largely atmospheric mode.

Rain

rainfallrainwaterrainstorm
This overall circulation pattern manifests itself in various ways, most clearly as anomalous rainfall.
The El Niño-Southern Oscillation affects the precipitation distribution, by altering rainfall patterns across the western United States, Midwest, the Southeast, and throughout the tropics.

Jet stream

jetstreampolar jet streamsubtropical jet stream
During the El Niño portion of ENSO, increased precipitation falls along the Gulf coast and Southeast due to a stronger than normal, and more southerly, polar jet stream.
El Niño-Southern Oscillation (ENSO) influences the average location of upper-level jet streams, and leads to cyclical variations in precipitation and temperature across North America, as well as affecting tropical cyclone development across the eastern Pacific and Atlantic basins.

Tipping points in the climate system

tipping pointrunaway climate changetipping points
The ENSO is considered to be a potential tipping element in Earth's climate and, under the global warming, can enhance or alternate regional climate extreme events through a strengthened teleconnection.
Other examples of possible large scale tipping elements are a shift in El Niño–Southern Oscillation.

Cyclonic Niño

increased tropical cyclone activityinfluencing ocean heat transportpotential effects
Coral-based reconstructions have been used in a 2011 study to infer that the El Niño Southern Oscillation already existed during the Pliocene, including discrete El Niño events.

Wind

windsgustsgust
El Niño–Southern Oscillation (ENSO) is an irregularly periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics.

Tropics

tropicaltropictropical zone
El Niño–Southern Oscillation (ENSO) is an irregularly periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics.

Atmospheric pressure

barometric pressureair pressurepressure
The Southern Oscillation is the accompanying atmospheric component, coupled with the sea temperature change: El Niño is accompanied by high air surface pressure in the tropical western Pacific and La Niña with low air surface pressure there.

Walker circulation

Walker
The two phases relate to the Walker circulation, which was discovered by Gilbert Walker during the early twentieth century.

Pressure-gradient force

pressure gradient forcedifference in atmospheric pressurepressure gradient
The Walker circulation is caused by the pressure gradient force that results from a High-pressure area over the eastern Pacific Ocean, and a low-pressure system over Indonesia.