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 New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>