(Press-News.org) El Niño and its partner La Niña, the warm and cold phases in the eastern half of the tropical Pacific, play havoc with climate worldwide. Predicting El Niño events more than several months ahead is now routine, but predicting how it will change in a warming world has been hampered by the short instrumental record. An international team of climate scientists has now shown that annually resolved tree-ring records from North America, particularly from the US Southwest, give a continuous representation of the intensity of El Niño events over the past 1100 years and can be used to improve El Niño prediction in climate models. The study, spearheaded by Jinbao Li, International Pacific Research Center, University of Hawai'i at Manoa, is published in the May 6 issue of Nature Climate Change.
Tree rings in the US Southwest, the team found, agree well with the 150-year instrumental sea surface temperature records in the tropical Pacific. During El Niño, the unusually warm surface temperatures in the eastern Pacific lead to changes in the atmospheric circulation, causing unusually wetter winters in the US Southwest, and thus wider tree rings; unusually cold eastern Pacific temperatures during La Niña lead to drought and narrower rings. The tree-ring records, furthermore, match well existing reconstructions of the El Niño-Southern Oscillation and correlate highly, for instance, with δ18O isotope concentrations of both living corals and corals that lived hundreds of years ago around Palmyra in the central Pacific.
"Our work revealed that the towering trees on the mountain slopes of the US Southwest and the colorful corals in the tropical Pacific both listen to the music of El Niño, which shows its signature in their yearly growth rings," explains Li. "The coral records, however, are brief, whereas the tree-ring records from North America supply us with a continuous El Niño record reaching back 1100 years."
The tree rings reveal that the intensity of El Niño has been highly variable, with decades of strong El Niño events and decades of little activity. The weakest El Niño activity happened during the Medieval Climate Anomaly in the 11th century, whereas the strongest activity has been since the 18th century.
These different periods of El Niño activity are related to long-term changes in Pacific climate. Cores taken from lake sediments in the Galapagos Islands, northern Yucatan, and the Pacific Northwest reveal that the eastern–central tropical Pacific climate swings between warm and cool phases, each lasting from 50 to 90 years. During warm phases, El Niño and La Niña events were more intense than usual. During cool phases, they deviated little from the long-term average as, for instance, during the Medieval Climate Anomaly when the eastern tropical Pacific was cool.
"Since El Niño causes climate extremes around the world, it is important to know how it will change with global warming," says co-author Shang-Ping Xie. "Current models diverge in their projections of its future behavior, with some showing an increase in amplitude, some no change, and some even a decrease. Our tree-ring data offer key observational benchmarks for evaluating and perfecting climate models and their predictions of the El Niño-Southern Oscillation under global warming."
INFORMATION:
This research was funded by the National Science Foundation, National Oceanic and Atmospheric Administration, Japan Agency for Marine-Earth Science and Technology, National Basic Research Program of China, and the National Natural Science Foundation of China.
Citation: Jinbao Li, Shang-Ping Xie, Edward R. Cook, Gang Huang, Rosanne D'Arrigo, Fei Liu, Jian Ma, and Xiao-Tong Zheng, 2011: Interdecadal modulation of El Niño amplitude during the past millennium. Nature Climate Change.
Researcher Contacts:
Jinbao Li (808) 956-5468; email: jinbao@hawaii.edu
Shang-Ping Xie (808) 956-6758; email: xie@hawaii.edu
Media Contact: Gisela Speidel (808) 956-9252; email: gspeidel@hawaii.edu
The International Pacific Research Center (IPRC) of the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawai'i at Mānoa, is a climate research center founded to gain greater understanding of the climate system and the nature and causes of climate variation in the Asia-Pacific region and how global climate changes may affect the region. Established under the "U.S.-Japan Common Agenda for Cooperation in Global Perspective" in October 1997, the IPRC is a collaborative effort between agencies in Japan and the United States.
Tree rings tell a 1,100-year history of El Niño
2011-05-08
ELSE PRESS RELEASES FROM THIS DATE:
Oregon's Complicated Drug Delivery Laws
2011-05-08
Oregon's Complicated Drug Delivery Laws
One of the most frequent complaints regarding Oregon State drug delivery charges is that the suspect never sold or delivered the drugs in question. "How can they charge me with delivery when I never sold anything?" The answer has to do with a tricky and dangerous quirk of Oregon's drug delivery laws.
Oregon law defines "delivery" as the "actual", "constructive", or "attempted" transfer of a controlled substance from one person to another. Problems arise for clients who are charged ...
Complying With Federal Safety Regulations Does Not Excuse Car Manufacturers
2011-05-08
Complying With Federal Safety Regulations Does Not Excuse Car Manufacturers
The United States Supreme Court recently issued an opinion that opens the door to personal injury and wrongful death lawsuits against car manufacturers under state law. The ruling against Mazda Motor of America came after the family of a woman killed in an motor vehicle accident involving a minivan sued Mazda in state court. The family claimed that Mazda was negligent in failing to install rear seat lap-and-shoulder seatbelts that could have prevented the woman's fatal injuries. Mazda argued ...
Insight into HIV immunity may lead to vaccine
2011-05-08
Latest insights into immunity to HIV could help to develop a vaccine to build antibodies' defences against the disease, a University of Melbourne, Australia study has found.
By investigating the action of the human antibodies called ADCC, in people with HIV, researchers were able to identify that the virus evolves to evade or 'escape' the antibodies.
Professor Stephen Kent of the University of Melbourne and one of the senior authors on the paper said ADCC antibodies have been strongly implicated in protection from HIV in several vaccine trials but their action was poorly ...
Chemistry curbs spreading of carbon dioxide
2011-05-08
The presence of even a simple chemical reaction can delay or prevent the spreading of stored carbon dioxide in underground aquifers, new research from the University of Cambridge has revealed.
The findings may have implications for carbon sequestration in saline aquifers – one of the many methods being explored to mitigate rising CO2 levels in the atmosphere.
Depending on the strength of the reaction between dissolved CO2 and porous rock, the new research shows that distinct scenarios of CO2 transport may occur in deep saline rock formations.
Jeanne Andres, a Schlumberger ...
Pentagonal tiles pave the way towards organic electronics
2011-05-08
For additional information please contact:
Genevieve Maul, Office of Communications, University of Cambridge
Tel: direct, +44 (0) 1223 765542, +44 (0) 1223 332300
Mob: +44 (0) 7774 017464
Email: Genevieve.maul@admin.cam.ac.uk
Notes to editors:
1. The paper is entitled "Weak intermolecular interactions in an ionically bound molecular adsorbate: Cyclopentadientyl/Cu(111)" and will be published in Physical Review Letters on Friday, 06 May.
2. Authors of the work:
- Surface, Microstructure and Fracture Group, Physics Department, Cambridge
(http://www.phy.cam.ac.uk/research/smf/)
Holly ...
The Effect of Bankruptcy on Credit Scores
2011-05-08
The Effect of Bankruptcy on Credit Scores
People who are mired in debt often dread the thought of filing for bankruptcy protection and the effect it will have on their credit scores. Many in this situation fear that they will never be able to obtain a loan, get a credit card or that they will be turned down for jobs, all because of a poor credit score.
As a matter of course, bankruptcy can have a serious effect on your credit score. It can lower your score by nearly 240 points. How much it will drop will depend on the type of debts you have and your prior credit history. ...
Computers sing to a better tune
2011-05-08
Music producers have for decades had electronics tricks at their disposal for improving a recorded vocal performance. They can add a little reverb or echo to bolster a weak rendition, use effects such as phasing and delay to add color to the vocal, fix duff notes with auto-tuning or even reprogram a whole melody line in software. In recent years, voice synthesis for converting text to spoken word has improved considerably but combining that technology with auto-tuning capability allows computers to "sing".
Software, such as Vocaloid, can successfully create lead vocals ...
Rice U. study: Daily deal promotions beneficial for certain kinds of startups
2011-05-08
In the first-of-its-kind analysis of Groupon's impact on a startup company, a new Rice University study found that the daily deal promotion was beneficial even though it had no material impact on the company's profits when unredeemed Groupons were not accounted for. When those unredeemed Groupons were factored in, the company had a substantial 30 percent increase in profits.
Having run the Groupon promotion, the company – Houston-based startup Gourmet Prep Meals (GPM) – had greater exposure and earned revenues almost 140 percent higher than it would have earned had it ...
Florida Legislature Looks at Better Criminal Identification Procedures
2011-05-08
Florida Legislature Looks at Better Criminal Identification Procedures
TV crime programs tend to suggest that every aspect of solving a crime lends itself to forensic science, as if CSI has been reduced to a magical formula. But in many criminal investigations, identification of the alleged perpetrator is still dependent on the recollections of eyewitnesses. And all too often, a false identification can lead to a prosecution of the wrong suspect in a homicide, sexual assault or theft case, all due to a convergence of unfortunate circumstances.
Florida legislators ...
From a bucket of seawater, new understanding of the ocean
2011-05-08
NEW BRUNSWICK, N.J. – From a bucket of seawater, scientists have unlocked information that may lead to deeper understanding of organisms as different as coral reefs and human disease. By analyzing genomes of a tiny, single-celled marine animal, they have demonstrated a possible way to address diverse questions such as how diseased cells differ from neighboring healthy cells and what it is about some Antarctic algae that allows them to live in warming waters while other algae die out.
Debashish Bhattacharya, professor of ecology, evolution and natural resources in Rutgers' ...