Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New study explains near-annual Monsoon oscillations generated by El Niño

20.10.2015

A new research study by a team of climate researchers from the University of Hawai'i at Mānoa explains for the first time the source of near-annual pressure and wind changes discovered previously in the Southeast Asian Monsoon system.

The results, published this week in the journal Proceedings of the National Academy of Sciences, show how the El Niño phenomenon interacts with the annual cycle of solar radiation in the western Pacific to generate a suite of new atmospheric pressure oscillations that affects wind and rainfall patterns in Southeast Asia, one of the densest populated areas on our planet.


Sea surface temperature anomalies [degrees Celsius] of September 2015 from NOAA's Extended Reconstructed Sea Surface Temperature (ERSST) dataset.

Credit: Smith et al., 2008: Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880-2006), J. Climate, 21, 2283-2296.

There still remain major uncertainties about how the atmospheric circulation and the rainfall patterns over Southeast Asia and the Western Tropical Pacific respond to El Niño conditions, such as the current 2015 event.

The new findings by Malte Stuecker and Fei-Fei Jin, from the Department of Atmospheric Sciences, and Axel Timmermann from the International Pacific Research Center at the University of Hawai'i, Mānoa demonstrate that the atmospheric reaction is much more predictable than previously assumed.

As a result of the developing and decaying El Niño conditions and the seasonal march of the sun across the equator, a series of near-annual atmosphere oscillations is generated with periods of about 24, 16, 10, and 8 months, each with its own characteristic pressure pattern.

All of these contribute to the formation of an extended and very persistent high pressure system over the western tropical Pacific, which peaks in January and re-emerges in the boreal summer of the following La Niña year.

"Known as the Philippine Sea Anticyclone, this pattern plays a pivotal role in how the effects of El Niño are expressed in Southeast Asia," explains Stuecker, climate scientist and lead author of the study. "In the past, many researchers looked at seasonal averages of wind and rainfall and missed the details of this variability," he adds.

"Our new theory also explains the observed persistence of the Philippine Sea Anticyclone, even months after El Niño warming has subsided and well into the subsequent La Niña summer. The effect of El Niño in winter is qualitatively similar to the effect of La Niña in summer. These effects occur when the phases of Pacific warming and the annual solar cycle coincide," says co-author Fei-Fei Jin, climate researcher and Professor at the Department of Atmospheric Sciences.

"These near-annual monsoon oscillations have some resemblance to the different ringing tones of a bell. Finding a new structure in the chaos of otherwise random weather variability has been very exciting, because it may open the door to enhanced seasonal predictability," says co-author Axel Timmermann, Professor at the Oceanography Department and the International Pacific Research Center.

The scientists emphasize that this mechanism provides a fundamentally new way to understand variability in the atmosphere on a large range of timescales and can be applied to a number of different climate phenomena.

Media Contact

Rachel Lentz
rlentz@hawaii.edu
808-956-8175

 @UHManoaNews

http://manoa.hawaii.edu 

Rachel Lentz | EurekAlert!

More articles from Earth Sciences:

nachricht Research sheds new light on forces that threaten sensitive coastlines
24.04.2017 | Indiana University

nachricht NASA sees the end of ex-Tropical Cyclone 02W
21.04.2017 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>