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El Niño has officially come to an end and the ripples from its demise will shake up weather around the globe. El Niño – a natural climate pattern marked by warmer than average ocean ...
El Niño and La Niña are climate patterns in the Pacific Ocean that can affect weather worldwide. Learn how they work, when they occur, and how they impact weather, ecosystems, and economies.
Apr 16, 2024 · El Niño is part of the natural climate phenomenon called the El Niño Southern Oscillation (ENSO). It has two opposite states: El Niño and La Niña, both of which significantly alter...
Jul 5, 2023 · The global weather pattern El Niño has returned for the first time in seven years, according to the World Meteorological Organization, setting the stage for further extreme weather and...
- Overview
- What is El Niño?
- Why El Niño occurs
- How El Niño affects North America via changes in jet stream
- El Niño summary: 2015 to 16
- What are the El Niño impacts in Canada?
- El Niño and climate change
- Quick facts on El Niño
This page describes the El Niño-Southern Oscillation (ENSO) phenomenon and provides information on the past and current impact of El Niño on the North American climate.
El Niño can be distinguished when the surface waters in the eastern tropical Pacific extending westward from Ecuador become warmer than average. The changing pattern of the Pacific Ocean causes a shift in the atmospheric circulation, which then impacts weather patterns across much of the earth.
El Niño is thought to occur due to changes in the normal patterns of trade wind circulation. Normally, these winds move westward across the tropical Pacific allowing upwelling of deep, cold water along the South American coast. For reasons not yet fully understood, these trade winds are sometimes reduced, or even reversed. Warmer waters slosh back toward the coast of South America and increase water temperatures in that region. Warmer water causes heat and moisture to rise from the ocean off the coast of Ecuador and Peru, resulting in more frequent storms and torrential rainfall over these normally arid regions.
Historically, El Niño events occur about every two to seven years and usually alternate with a cold phase and a warm phase in the eastern and central tropical Pacific.
Atmospheric circulation departure from normal
El Niño winter El Niño Winter. Click for more details. Typical air pressure anomaly in decameters (1 decameter = 10 meters) at 500 hectopascals (at an altitude of about 5 km) during past strong El Niños. Blue areas show below normal pressure, while higher-than-normal pressure occurs in the red regions. With a ridge of high pressure, most of Canada experiences above normal winter temperatures. Thick black lines indicate position of jet streams. The subtropical jet stream shifts farther south, and storms associated with this jet stream produce wet weather in California and the southern portions of the United States (represented by the blue areas;) and relatively milder and drier than normal weather in the northern United States and Canada (represented by the red areas;).
In terms of sea surface temperature anomalies in the Equatorial Pacific, the great El Niño of 2015-16 equalled the El Niño episode registered in 1997-1998. These two episodes are the strongest El Niño events observed in the recent decades. However, when measuring additional parameters, such as shifts in atmospheric deep convection and subsurface ocean temperatures, the 2015-16 event is considered to be weaker than the great El Niño of 1997-98. These two parameters are regarded as critical for El Niño’s impact on remote regions such as Canada or the United States. Yet, the 2015-16 boreal winter had most of the characteristics of a typical El Niño winter, based on El Niño historical events.
•The 2015-16 El Niño officially started in March 2015 and ended in May 2016, according to the National Oceanic and Atmospheric Administration (NOAA) El Niño Advisories.
•Over Canada, winter 2015-16 (Dec-Jan-Feb) was one to five degree Celsius warmer than normal across all provinces with especially unseasonal warmth in Quebec, the central Prairies, and Yukon. Subsequently, the 2016 spring remained warmer than normal in the western Canada and the Prairies, while an inflow of cold Arctic air led to colder than normal conditions over Eastern and Northeastern Canada.
•The 2015-16 El Niño brought moderate relief to the severe drought that has persisted in California since 2011, except in the southern part of the state where precipitation remained below normal.
•By shifting the convection centers in the Equatorial Pacific, the 2015-16 El Niño contributed to a weaker Indian monsoon in summer 2015, drought in Central America during summer 2015, drought in Indonesia during the fall 2015 and flooding in northern Peru in fall 2015.
•The year 2015 was the warmest year recorded since sufficiently accurate observations became available in the late 1800s, according to several meteorological agencies. This was due to the combined influences of the 2015-16 El Niño and the overall warming trend of the Earth’s climate. Furthermore, the previous temperature record established in 2014 was broken by the highest margin recorded to date.
Historically, Canada is mostly affected by El Niño during winter and spring. Milder than normal winters and springs occur in Western, Northwestern and Central Canada. Generally, El Nino does not significantly impact Eastern Canada, including the Maritimes, but it may reduce tropical cyclone activity in the Atlantic Ocean.
Climate scientists are studying whether climate change, as a result of anthropogenic effects such as the enhanced greenhouse effect, may be affecting the observed increase in strength and frequency of El Niño events since the late 1970s. Currently, a direct link between El Niño and climate change has not been found. The strengthening subtropical j...
•The phrase "El Niño" refers to the Christ Child and was coined by fishermen along the coasts of Ecuador and Peru to describe the warm ocean current that typically appeared around Christmas time and lasted for several months.
•El Niño is the second largest driver of the world's climate, second only to normal seasonal warming and cooling, which also brings changes in precipitation patterns.
•El Niño events appear approximately every two to seven years. They typically last 12 to 18 months. In the early 1990s, a prolonged El Niño persisted for four years.
•El Niño events have been documented since the early 1700s. More detailed observations from ships led to instrumental record keeping in the earlier half of the twentieth century. It is only since the 1970s, however, that scientists began linking El Niño to massive flooding and severe droughts around the world.
•Several geographical zones are used in the equatorial Pacific to monitor El Nino development and propagation: Nino 1+2 zone is near the South America coast tends to warm up first, Nino 3 is prominent for large sea surface temperature (SST) variability, Nino 3.4, in the central Pacific, includes the key region for coupled atmospheric-ocean interactions. Nino 4, in the western Pacific, serves as a strong indicator for precipitation.
•About every four to five years, a pool of cooler-than-normal water develops off South America. The effects of this cooler water are called La Niña. This usually brings colder winters to the Canadian west and Alaska and drier, warmer weather to the American southeast.
Oct 19, 2023 · El Niño is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean. El Niño is the “warm phase” of a larger phenomenon called the El Niño-Southern Oscillation (ENSO). La Niña, the “cool phase” of ENSO, is a pattern that describes the unusual cooling of the region’s surface waters.
People also ask
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Why is El Nino so important?
El Niño–Southern Oscillation (ENSO) is a global climate phenomenon that emerges from variations in winds and sea surface temperatures over the tropical Pacific Ocean. Those variations have an irregular pattern but do have some semblance of cycles. The occurrence of ENSO is not predictable.
