El Niño – Southern Oscillation ( ENSO ), or El Niño / La Niña – Southern Oscillation, is a quasiperiodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years.

The Southern Oscillation refers to variations in the temperature of the surface of the tropical eastern Pacific Ocean ( warming and cooling known as El Niño and La Niña respectively ) and in air surface pressure in the tropical western Pacific.

The two variations are coupled: the warm oceanic phase, El Niño, accompanies high air surface pressure in the western Pacific, while the cold phase, La Niña, accompanies low air surface pressure in the western Pacific.

The extremes of this climate pattern's oscillations, El Niño and La Niña, cause extreme weather ( such as floods and droughts ) in many regions of the world.

When this warming or cooling occurs for only seven to nine months, it is classified as El Niño / La Niña " conditions "; when it occurs for more than that period, it is classified as El Niño / La Niña " episodes ".

While not a direct cause of El Niño, the Madden-Julian Oscillation, or MJO, propagates rainfall anomalies eastward around the global tropics in a cycle of 30 – 60 days, and may influence the speed of development and intensity of El Niño and La Niña in several ways.

La Niña Conditions.

The exact opposite heating and atmospheric pressure anomalies occur during La Niña.

Sea surface skin temperature anomalies in November 2007 showing La Niña conditions

La Niña is the name for the cold phase of ENSO, during which the cold pool in the eastern Pacific intensifies and the trade winds strengthen.

The name La Niña originates from Spanish, meaning " the girl ", analogous to El Niño meaning " the boy ".

La Niña results in wetter-than-normal conditions in Southern Africa from December to February, and drier-than-normal conditions over equatorial East Africa over the same period.

During La Niña years, the formation of tropical cyclones, along with the subtropical ridge position, shifts westward across the western Pacific ocean, which increases the landfall threat to China.

In March 2008, La Niña caused a drop in sea surface temperatures over Southeast Asia by an amount of 2 ° C.

During a time of La Niña, drought plagues the coastal regions of Peru and Chile.

Regional impacts of La Niña.

La Niña causes mostly the opposite effects of El Niño.

In Canada, La Niña will in general cause a cooler, snowier winter, such as the near-record-breaking amounts of snow recorded in the La Niña winter of 2007 / 2008 in Eastern Canada.

The clearing of land for agricultural purposes occurs throughout Honduras but especially in the largely undeveloped La Mosquitia region, and causes further land degradation and soil erosion hastened.

* 1878: Paul Bert publishes La Pression barométrique, providing the first systematic understanding of the causes of DCS.

La Niña often causes drought conditions in the western Pacific ; flooding in northern South America ; mild wet summers in northern North America, and drought in the southeastern United States.

In La Seule France ( 1941 ) Maurras argued for a policy of France d ' abord (" France First "), whereby France would restore itself politically and morally under Pétain, resolving the root causes in his eyes of France's defeat in 1940, before dealing with the issue of the foreign occupation.

In 1867 – 1868 Becquerel published a treatise in two volumes called La Lumière, ses causes et ses effets.

His philosophical writings were La morale d ' Épicure tirée de ses propres écrits ( 1758 ), and the Histoire des causes premières ( 1769 ).

La Maga also has an infant son, Rocamadour, whose appearance in France causes a crisis in the relationship between Lucia and Oliveira.

Well known in Hawaii for her support of philanthropic causes, she helped found La Pietra: Hawaii School for Girls and served as its Chair from 1978 until her death in Honolulu in 2007, aged 84, following an extended illness.

After they lift off from the roof, several warheads hit and the EMP from the detonations causes the helicopter to crash into the La Brea Tar Pits.

She gave her royalties for her album Comme si de rien n ’ était to the Fondation de France, and supports different events or causes, such as the Born HIV Free campaign, animal rights, the Nelson Mandela foundation, the French association Aides for AIDS research, the French association La Chaîne de l ' Espoir or the association Warchild UK.

Born into a Huguenot family, Constant led a less structured life, first embracing Protestantism and then the Catholic causes, visiting England and then in 1626 betraying the Protestants by revealing English plans to take La Rochelle.

An especially strong Walker circulation causes a La Niña, resulting in cooler ocean temperatures due to increased upwelling.

In addition to her philanthropic work with The Bonita Trust, Parasol also supports community-related causes in Israel, Poland, and Spain, including Tel Aviv University, The Museum of The History of Polish Jews in Warsaw, and The Prodean Animal Rescue Center in La Linea, Spain.

This causes a rift in La Onda and Carlos, one of the main members who wants to deal cocaine, leaves the gang to work with the Aryans, doing this causes other members to leave as well.

According to NOAA, " Expected La Niña impacts during November – January include a continuation of above-average precipitation over Indonesia and below-average precipitation over the central equatorial Pacific.

The same La Niña event is also a likely cause of a series of tornadoes of above-average severity that struck the Midwestern and Southern United States in the spring of 2011, and is currently a major factor in the drought conditions persisting in the South Central states including Texas, Oklahoma and Arkansas.

The innermost part of this domain is more quite dry while the mountainous part reach slightly higher precipitation figures which allow Kermes Oak woods to thrive, such as the one in La Carrasqueta or in the Mariola range, both near Alcoi.

Yet, unlike other portions of Luzon and the Philippines ' two other island groupings, the Visayas and Mindanao, La Union experiences a rather arid and prolonged dry season with little precipitation to be expected between the months of November and May.

La Serena has a cool desert climate, similar to nearby places in that it is clearly seasonal – in Summer there is an absence of precipitation, but with abundant morning cloudiness and drizzles.

La Esperanza receives average annual precipitation of 1400 mm.

La Pouquelaye de Faldouet was constructed on a site on the East coast looking across to the Cotentin Peninsula.

He was born as Charles-Édouard Jeanneret-Gris in La Chaux-de-Fonds, a small city in Neuchâtel canton in north-western Switzerland, in the Jura mountains, just across the border from France.

The Ferrocarril Central Andino ( FCCA ; the former Ferrocarril Central del Perú ) runs inland from Callao and Lima across the Andes watershed to La Oroya and Huancayo.

* A daily ferry service known as the Cataño Ferry, ( La Lancha de Cataño in Spanish ) which operates a route across San Juan Bay between Old San Juan and the municipality of Cataño.

At least one scholar, however, decries that out of seven principal black characters across the Star Trek series, only La Forge and Tuvok " really qualify as nerds, and neither of them compares with the extraordinary geekiness of the teenaged Wesley Crusher.

Archaeologically, the Gauls were bearers of the La Tène culture, which extended across all of Gaul, as well as east to Rhaetia, Noricum, Pannonia and southwestern Germania.

The construction of La Grande Arche in La Défense places the tower in a second line of perspective across Paris: see Axe historique.

Near the confluence of the Illinois with the La Moine River, it turns south, flowing roughly parallel to the Mississippi across southwestern Illinois.

In memory of the brave heroes of the Battle of La Concepcion in 1882, on 10 July each year, the very day the final Chilean soldiers in La Concepcion died in defense of the Chilean nation, this Pledge to the Flag ( Juramento de la Bandera ) is recited at all installations and military bases of the Chilean Army, Chilean Navy and Chilean Air Force across the nation in remembrance of this great moment in Chilean history.

During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3 – 5 ° C.

At the mouth of the Trempealeau River, which flows from northeast to southwest across the county on its way to the Mississippi River, they found a bluff surrounded by water and called it " La Montagne qui trempe à l ’ eau ," which means " mountain with its foot in the water.

While Cotulla continued to develop his town, Iuka's postmaster, Jesse Laxton, developed a townsite just across the tracks named La Salle.

In late 2007, photographs featuring De La Hoya cross-dressed in company of a woman not his wife were posted on a tabloid website and received extensive publicity across the internet.

The Plomosa Mountains lie across the La Posa Plain to the east.

Typical passage to La Petite Chute included crossing the Atlantic from Rotterdam to New York City, a train trip from there to Albany, a train or Erie Canal-barge trip across New York state to Buffalo, steamship travel through the Great Lakes and Green Bay to the head of the Fox River at Green Bay and finally a 30-mile, ox-cart trip to the mission at La Petite Chute.

Between 1673 and 1689 La Salle opened another water route from the St. Lawrence River, through the Niagara and the Great Lakes and across the Chicago portage to the Mississippi.

The 20th ( Light ) Division forced a way through La Vacquerie and then advanced to capture a bridge across the St Quentin canal at Masnières.

At the time, the new location was just across the San Antonio River from the town of San Antonio de Bexar, and just north of a group of huts known as La Villita.

After the war she sang at La Scala and in other major centres across Europe.