Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Volcanic eruptions may affect El Niño onset

20.11.2003


A new study by scientists at the University of Virginia (UVa) in Charlottesville and the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, suggests that explosive volcanic eruptions in the tropics may increase the probability of an El Niño event occurring during the winter following the eruption. The research was funded by the National Science Foundation (NSF).



"The El Niño-Southern Oscillation (ENSO) is the dominant mode of interannual climate variability on the planet," says NCAR scientist Caspar Ammann. "When thinking about long-term climate, we must ask whether this system itself undergoes changes, perhaps in response to changes in radiative forcing or in the background climate itself. Our findings, based on two reconstructions, suggest that it indeed might."

When a volcano erupts in the tropics, its aerosol emissions spread into the stratosphere across the northern and southern hemispheres, reflecting some of the sun’s heat back toward space and thereby cooling the Earth’s atmosphere. This cooling alters the interaction between the oceans and atmosphere, possibly encouraging a warming response in the Pacific Ocean as the massive body of water attempts to restore an initial equilibrium.


"Our results suggest that the atmospheric cooling from an eruption may help nudge the climate system towards producing an El Niño event," said Michael Mann, an environmental scientist at the University of Virginia. The study results will appear in the November 20 issue of the journal Nature.

"This research illustrates the value of paleoclimate studies that draw on research from disparate fields to uncover connections," said David Verardo, director of NSF’s paleoclimate program, which funded the research. "Studies of modern climate conditions gleaned from thermometers and barometers can only get you so far. Challenging the conventional wisdom, as this research does, is necessary to achieve a comprehensive understanding of Earth’s climate," he said.

Some scientists had previously noted that during the 20th century, El Niño events–the periodic warming of sea surface temperatures in the equatorial Pacific–tended to follow the eruption of volcanoes in the tropics. But that 100-year period, the only time span for which reliable instrumental records were kept, was considered too short a duration to substantiate a link between the two phenomena. The connection was thought to be coincidental. "So we turned to the paleoarchives for a longer history," Mann said. "We actually didn’t expect the relationship to hold up in the long run."

The scientists instead found that, when looking back over a 350-year period, as far back as paleorecords allow, there was credible evidence that volcanic activity in the tropics may play a significant role in the occurrence of El Niño events. "We now have a long record showing that the relationship between volcanic eruptions and an increased probability of El Niño events continues to hold up over several centuries," Mann said. "It’s probably not just a fluke."

Mann, Ammann, and UVa scientist Brad Adams used the paleoclimate records stored in ice cores, corals, and tree ring records to reconstruct El Niño events. They used independent ice-core volcanic dust evidence to reconstruct volcanic activity back to the early 1700s.

The paleoclimate records are called ’proxy records’ because they are not direct measurements of current climate and ocean conditions, but instead are reconstructions of past conditions gleaned from the physical, biological, or chemical records or, "signatures," stored in natural archives in the environment. Using these records, the scientists were able to precisely identify the years when eruptions occurred and the years when El Niño events occurred.

When they counted, year by year, the separate events and brought them together for comparison, they found that there was a nearly one-in-two chance that an El Niño event will occur after a volcanic eruption in the tropical zone, roughly double the normal probability. "I wouldn’t call this a tight connection – it’s not a one-to-one relationship," Mann said, "but it appears that the eruption of a tropical volcano nudges the climate towards a more El Niño-like state."

El Niño is a prominent altering factor on world climate, affecting weather patterns for months and years, often causing drought and severe weather in different parts of the world. "We seek to understand how El Niño responds to changes in natural factors such as volcanic activity in part, so we can potentially better understand how El Niño might respond to more recent human influences on climate," Mann said.

Adams added that the findings might help oceanographers and atmospheric scientists to make better probabilistic forecasts of El Niño activity. "This is not a strictly predictive tool, but it may help in anticipating the odds that an El Niño event might occur in a given period," Adams said.


The National Oceanic and Atmospheric Administration also sponsored the research.
NSF Program Contact: Dave Verardo, dverardo@nsf.gov.

Cheryl Dybas | NSF
Further information:
http://www.nsf.gov

More articles from Earth Sciences:

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>