Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Giant see-saw of monsoon rains detected


When the summer rains in China are weak, they are strong in Australia, and vice versa – scientists have discovered a previously unknown see-saw relationship between these two monsoon regions. This effect does not occur from one year to another, but on decadal and centennial time scales. To detect the pattern, the team developed a novel mathematical method to analyze traces of climatic events of the past 9000 years archived in ancient dripstones from caves.

The regional monsoon has huge effects on agriculture and hence on the livelihoods of half of the world’s population, including India and Indonesia. Understanding how seasonal periods of rainfall in the Northern and Southern Hemispheres of our planet are linked is important for assessing possible long-distance effects of climate change.

“We’ve been surprised by how clearly the ups and downs of precipitation in East Asia on the one hand and Australia on the other hand are opposed, it’s really a giant see-saw,” says Deniz Eroglu from the Potsdam Institute for Climate Impact Research (PIK) and University of São Paulo, lead author of the study to be published in Nature Communications. “We needed to cut through the data clutter to detect this pattern. While our method of sophisticated statistical time series data analysis might seem quite complicated, our findings have substantial real-world consequences.”

Data from caves in China and Australia – these countries are most affected

Australia, just like China, heavily depends on the monsoon summer rains. “Both countries have experienced drier and wetter periods in the past. For instance the Northwest of Australia’s tourism and agriculture industries are vulnerable to flooding and bush fires, so any change from the current precipitation pattern will have huge impacts for the people living here,” says co-author Thomas Stemler from the University of Western Australia.

“However, this is an issue way beyond the region – in fact, the East-Asian-Indonesian-Australian summer monsoon provides a heat source that drives global circulation of airstreams during what is the winter season in the US, Russia and Europe. It will be exciting to investigate how the see-saw we found may be affecting these far-away parts of the world.”

Since there are no direct records of monsoon dynamics over past millennia, the scientists need to work with indirect data evidence. “Dripstones in ancient caves are amazing witnesses of the Earth’s past. Since they’re growing just fractions of a millimeter per year, we can see changes in the chemical composition over time from one layer to another,” says co-author Norbert Marwan from PIK who himself explored various caves, for instance in India. For the new study, the team used data from Dongge Cave in Southern China and cave KNI-51 in Northwestern Australia.

“Though it might seem challenging to climb into the caves to access the dripstones,” says Marwan, “the real challenge is to decrypt the information they carry – analyzing thousands of isotope samples and attributing them to specific climatic conditions. For this, we need sophisticated statistics.” A key partner in this process has been the Institute for Geology, Mineralogy & Geophysics at Ruhr-Universität Bochum.

Mechanics of the heavens are a driver, but human-made warming can change the dynamics

“The monsoon see-saw is likely driven by factors humans cannot influence, including the tilt of our Earth’s axis and solar activity, so that’s celestial mechanics,” says co-author Jürgen Kurths, co-chair of PIK’s research domain Transdisciplinary Concepts and Methods.

“However, disturbing circulation and precipitation patterns is something we unfortunately can do and already are doing by emitting greenhouse gases and thereby warming our planet. Understanding the natural East-Asian-Australian monsoon variability will help us to better understand certain human-caused climate risks in the future.”

Article: Deniz Eroglu, Fiona H. McRobie, Ibrahim Ozken, Thomas Stemler, Karl-Heinz Wyrwoll, Sebastian F. M. Breitenbach, Norbert Marwan, Jürgen Kurths (2016): See-saw relationship of the Holocene East Asian-Australian summer monsoon. Nature Communications [10.1038/NCOMMS12929]

Weblink to the article once it is published:

For further information please contact:
PIK press office
Phone: +49 331 288 25 07
Twitter: @PIK_Climate

Mareike Schodder | Potsdam-Institut für Klimafolgenforschung

More articles from Earth Sciences:

nachricht Wandering greenhouse gas
16.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Unique Insights into the Antarctic Ice Shelf System
14.03.2018 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>