Tropical Pacific climate variations and their global weather impacts may be predicted much further in advance than previously thought, according to research by an international team of climate scientists from the USA, Australia, and Japan. The source of this predictability lies in the tight interactions between the ocean and the atmosphere and among the Atlantic, the Pacific and the Indian Oceans. Such long-term tropical climate forecasts are useful to the public and policy makers.
At present computer simulations can predict the occurrence of an El Niño event at best three seasons in advance. Climate modeling centers worldwide generate and disseminate these forecasts on an operational basis. Scientists have assumed that the skill and reliability of such tropical climate forecasts drop rapidly for lead times longer than one year.
This image shows inter-basin coupling as a cause of multi-year tropical Pacific climate predictability: Impact of Atlantic warming on global atmospheric Walker Circulation (arrows). Rising air over the Atlantic subsides over the equatorial Pacific, causing central Pacific sea surface cooling, which in turn reinforces the large-scale wind anomalies.
Credit: Yoshimitsu Chikamoto
The new findings of predictable climate variations up to three years in advance are based on a series of hindcast computer modeling experiments, which included observed ocean temperature and salinity data. The results are presented in the April 21, 2015, online issue of Nature Communications.
"We found that, even three to four years after starting the prediction, the model was still tracking the observations well," says Yoshimitsu Chikamoto at the University of Hawaii at Manoa International Pacific Research Center and lead author of the study. "This implies that central Pacific climate conditions can be predicted over several years ahead."
"The mechanism is simple," states co-author Shang-Ping Xie from the University of California San Diego. "Warmer water in the Atlantic heats up the atmosphere. Rising air and increased precipitation drive a large atmospheric circulation cell, which then sinks over the Central Pacific. The relatively dry air feeds surface winds back into the Atlantic and the Indian Ocean. These winds cool the Central Pacific leading to conditions, which are similar to a La Niña Modoki event. The central Pacific cooling then strengthens the global atmospheric circulation anomalies."
"Our results present a paradigm shift," explains co-author Axel Timmermann, climate scientist and professor at the University of Hawaii. "Whereas the Pacific was previously considered the main driver of tropical climate variability and the Atlantic and Indian Ocean its slaves, our results document a much more active role for the Atlantic Ocean in determining conditions in the other two ocean basins. The coupling between the oceans is established by a massive reorganization of the atmospheric circulation."
The impacts of the findings are wide-ranging. "Central Pacific temperature changes have a remote effect on rainfall in California and Australia. Seeing the Atlantic as an important contributor to these rainfall shifts, which happen as far away as Australia, came to us as a great surprise. It highlights the fact that on multi-year timescales we have to view climate variability in a global perspective, rather than through a basin-wide lens," says Jing-Jia Luo, co-author of the study and climate scientist at the Bureau of Meteorology in Australia.
"Our study fills the gap between the well-established seasonal predictions and internationally ongoing decadal forecasting efforts. We anticipate that the main results will soon be corroborated by other climate computer models," concludes co-author Masahide Kimoto from the University of Tokyo, Japan.
Citation: Chikamoto, Y., A. Timmermann, J.-J. Luo, T. Mochizuki, M. Kimoto, M. Watanabe, M. Ishii, S.-P. Xie, and F.-F. Jin: Skilful multi-year predictions of tropical trans-basin climate variability. Nature Communications, 6:6869, doi: 10.1038/ncomms7869 (2015).
This study was supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology, through the Program for Risk Information on Climate Change. The simulations were performed with the Earth Simulator at the Japan Agency for Marine-Earth Science and Technology and the NEC SX-8R at the National Institute for Environmental Studies. A. T. and Y. C. were supported by NSF (1049219); S.P. Xie by NSF and NOAA.
Yoshimitsu Chikamoto International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, Hawaii 96822; email: email@example.com; phone: (808) 956-9054.
Axel Timmermann, Professor of Oceanography, International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, Hawaii 96822; email: firstname.lastname@example.org; phone: (808) 956-2720.
Fei-Fei Jin, Professor Department of Meteorology, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, Hawaii 96822; email: email@example.com; phone: (808) 956-4645.
International Pacific Research Center Media Contact:
Gisela E. Speidel, International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, Hawaii 96822; email: firstname.lastname@example.org; phone (808) 956-9252.
Gisela Speidel | EurekAlert!
Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen
Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research