La Niña is a complex weather pattern that occurs every few years, as a result of variations in ocean temperatures in the equatorial
Equator
An equator is the intersection of the surface of a rotating sphere with the plane that is perpendicular to the sphere's axis of rotation and midway between its poles. The equator usually refers to the Earth's equator: an imaginary line on the Earth's surface equidistant from the North Pole and Sout…
Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean in the south and is bounded by Asia and Australia in the west and the Americas in the east.
What is the climate pattern of La Nina?
Encyclopedic Entry. Vocabulary. La Niña is a climate pattern that describes the cooling of surface ocean waters along the tropical west coast of South America. La Nina is considered to be the counterpart to El Nino, which is characterize d by unusually warm ocean temperatures in the equatorial region of the Pacific Ocean.
What is the purpose of the Oceanic Nino Index?
Scientists use the Oceanic Nino Index to measure the deviations from normal sea-surface temperatures that El Niño and La Niña produce in the east-central Pacific Ocean.
But during La Niña..
In a La Niña year, the winds above the Pacific Ocean are much, much stronger than usual. This usually happens once every few years. The winds are so strong during a La Niña (Spanish for "the girl") that they push lots of warm ocean water west toward Indonesia. And that means that lots of cold water rises to the surface near South America.
What's the difference between El Niño and La Niña?
Both events start in the Pacific Ocean, but they are opposites in almost every other way! La Niña causes water in the eastern Pacific to be colder than usual. In the same region, El Niño can cause the water to be warmer than usual. So, areas that are hit with drought during La Niña years can get lots of rain in El Niño years!
Overview
Background
La Niña is a complex weather pattern that occurs every few years, as a result of variations in ocean temperatures in the equatorial band of the Pacific Ocean, The phenomenon occurs as strong winds blow warm water at the ocean's surface away from South America, across the Pacific Ocean towards Indonesia. As this warm water moves west, cold water from the deep sea rises to the surface near South America; it is considered to be the cold phase of the broader El Ni…
Impacts on the global climate
La Niña impacts the global climate and disrupts normal weather patterns, which can lead to intense storms in some places and droughts in others.
Regional impacts
Observations of La Niña events since 1950 show that impacts associated with La Niña events depend on what season it is. However, while certain events and impacts are expected to occur during these periods, it is not certain or guaranteed that they will occur.
La Niña results in wetter-than-normal conditions in southern Africa from Dece…
Diversity
The ‘traditional’ or conventional La Niña is called an Eastern Pacific (EP) La Niña; it involves temperature anomalies in the eastern Pacific. However, aside from differences in diagnostic criteria, non-traditional La Niñas were observed in the last two decades, in which the usual place of the temperature anomaly (Niño 1 and 2) is not affected, but rather an anomaly arises in the central Pacific (Niñ…
See also
• 2000 Mozambique flood (attributed to La Niña)
• 2010 Pakistan floods (attributed to La Niña)
• 2010–2011 Queensland floods (attributed to La Niña)
• 2010–2012 La Niña event
Footnotes
1. ^ Each forecast agency has a different criteria for what constitutes a La Niña event, which is tailored to their specific interests. For example, the Australian Bureau of Meteorology looks at the trade winds, SOI, weather models and sea surface temperatures in the Niño 3 and 3.4 regions before declaring that a La Niña event has started. However, the Japan Meteorological Agency declares that a La Niña event has started when the average five-month sea surface temperature …
External links
• "Current map of sea surface temperature anomalies in the Pacific Ocean". earth.nullschool.net.
• "Southern Oscillation diagnostic discussion". Climate Prediction Center (CPC). National Oceanic and Atmospheric Administration.
• "ENSO Outlook - An alert system for the El Niño–Southern Oscillation". Australian Bureau of Meteorology.