Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Leftover warm water in Pacific Ocean fueled massive El Niño

10.05.2016

A new study provides insight into how the current El Niño, one of the strongest on record, formed in the Pacific Ocean. The new research finds easterly winds in the tropical Pacific Ocean stalled a potential El Niño in 2014 and left a swath of warm water in the central Pacific. The presence of that warm water stacked the deck for a monster El Niño to occur in 2015, according to the study's authors.

El Niño and La Niña are the warm and cool phases of a recurring climate pattern across the tropical Pacific Ocean called the El Niño-Southern Oscillation, or ENSO. The warm and cool phases shift back and forth every two to seven years, and each phase triggers predictable disruptions in temperature, wind, and rain across the globe.


This is a comparison of the 2015 and 1997 El Niños, two of the strongest on record, in October of each respective year. Observations of sea surface heights and temperatures, as well as wind patterns, show surface waters cooling off in the Western Pacific and warming significantly in the tropical Eastern Pacific.

Credit: NASA's Earth Observatory.

During El Niño events, water temperatures at the sea surface are higher than normal. Low-level surface winds, which normally blow east to west along the equator, or easterly winds, start blowing the other direction, west to east, or westerly.

In the spring of 2014, strong westerly winds near the equator in the western and central Pacific Ocean created a buzz among scientists - they saw the winds as a sign of a large El Niño event to come in the winter of 2014, said Aaron Levine, a climate scientist at the NOAA Pacific Marine Environmental Laboratory in Seattle, Washington, and lead author of the new study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

But as the summer progressed, El Niño didn't form the way scientists expected it to: sea surface temperatures in the eastern Pacific never warmed enough to truly be called an El Niño, and the buzz fizzled out.

But then, in the spring of 2015, episodes of very strong westerly wind bursts occurred and became more frequent throughout the summer. Following a pattern set by previous large El Niños, 2015 to 2016 became one of the three strongest El Niños on record, along with 1982 to 1983 and 1997 to 1998, Levine said.

Levine and others wondered whether the stalled El Niño from 2014 and the monster El Niño of 2015 were somehow related, he said.

In the new study, Levine and co-author Michael McPhaden, fellow climate scientist at the NOAA Pacific Marine Environmental Laboratory, examined changes in sea surface and sub-surface temperatures, winds, and volumes of warm water in the Pacific Ocean from 2014 to 2016. They also used a mathematical model to analyze how these factors were related.

"As an El Niño develops and matures into its peak phase, [warm water] gets discharged out of the equatorial regions to the polar regions," Levine said. In 2014, easterly winds prevented that warm water from being transported poleward.

The warm water stuck around through the winter and was available as a reservoir of heat that could be tapped into the following year. "Once we started to get some additional westerly winds - unusually strong westerly winds that occurred in the spring and summer of 2015 - an El Niño developed," he said.

Looking further back into the climate record, Levine and McPhaden found a similar event occurred in 1990. That year, easterly winds counteracted a budding El Niño, and leftover warm water fueled El Niño conditions in 1991 to 1992.

"It's nice to see that even in the 35-year record we have something similar that gives us confidence that this was the physical mechanism that was going on," Levine said.

Predicting future El Niños

While Levine's research shows what conditions can help to explain past El Niños, predicting future El Niños is much more difficult. For example, warm sea surface temperatures make it more likely for an El Niño to occur, but cannot be used to predict El Niños with absolute certainty, Levine said.

Sea surface temperatures and winds are closely coupled - meaning that they strongly influence each other, said Michelle L'Heureux, a climate scientist at NOAA's Center for Weather and Climate Prediction in College Park, Maryland, who was not involved in the new study. According to L'Heureux, certain winds are predictable to a certain degree, but there are still elements of surprise.

"The wildcard in all of this - the reason this is very probabilistic and we can't say anything with certainty - is that some part of the winds are essentially random," L'Heureux said. "We can predict them five to seven days out, but that's not going to give you much advance information on the growth of ENSO."

These random wind elements are a major limitation to predicting El Niño events, she said. "There's a chance that the winds could turn off in the summertime, and that's what happened in 2014."

###

The American Geophysical Union is dedicated to advancing the Earth and space sciences for the benefit of humanity through its scholarly publications, conferences, and outreach programs. AGU is a not-for-profit, professional, scientific organization representing more than 60,000 members in 139 countries. Join the conversation on Facebook, Twitter, YouTube, and our other social media channels.

AGU Contact:
Nanci Bompey
+1 (202) 777-7524
nbompey@agu.org

NOAA Contact:
John Ewald
+1 (240) 429-6127
john.ewald@noaa.gov

http://www.agu.org 

Nanci Bompey | American Geophysical Union

More articles from Earth Sciences:

nachricht NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>