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 By saving cost and energy, the lighting revolution may increase light pollution
23.11.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

nachricht Frictional Heat Powers Hydrothermal Activity on Enceladus
23.11.2017 | Universität Heidelberg

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Water cooling for the Earth's crust

23.11.2017 | Earth Sciences

Nano-watch has steady hands

23.11.2017 | Physics and Astronomy

Batteries with better performance and improved safety

23.11.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>