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 GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center

nachricht Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>