Across the edges of the Indian Ocean, the amount of rainfall differs greatly
If it rains particularly hard in the Sumatran rain forest, the already arid region of East Africa is onset with drought. Researchers from the Biodiversity and Climate Research Centre (BiK-F), the California Institute of Technology, the Univerity of Southern California and the University of Bremen found that this cyclic, bipolar climate phenomenon has likely been around for 10,000 years. The pilot study, published today in, "Proceedings of the National Academy of Sciences," sheds light on the climate system of a region whose rainfall patterns have a major impact on global climate.
The tropics play a critical role in the global climate system, in part because they are the origin of weather extremes such as El Niño and the monsoon. One of the most important regions, in this case, is the Indo-Pacific region in Southeast Asia. It is the largest source of atmospheric water vapor as well as receiving the greatest amount of rainfall on Earth. A team of researchers has now explored precipitation changes off the coast of western Indonesia during the last 24,000 years with the aim to better understand patterns and dynamics of local precipitation.
Climate phenomenon in the Indian Ocean has been around for 10,000 years
According to the researchers, it is likely that the so called, "Indian Ocean Di-pole," has been a recurrent feature of the regional climate system for the past 10,000 years. At present, this seasonal event occurs about every five to seven years. Among other things, it includes anomalous precipitation patterns in the eastern and western edges of the Indian Ocean, which are linked. The precipitation dipole is such that higher rainfall on the west coast of Indonesia corresponds to less rainfall in East Africa, and vice versa. The new study, which looked at 30-year averages of rainfall amounts, revealed that a similar pattern has persisted for the past 10,000 years. "Such insights into the past may help to separate natural from ‘man-made’ oscillations of rainfall which is particularly important in view of ongoing climate change," says the lead author of the study, Dr. Eva Niedermeyer, LOEWE Biodiversity and Climate Research Centre (BiK-F).
Proof of past climatic conditions found in terrestrial plant waxes
Niedermeyer and her colleagues worked on a marine sediment core which was collected off the coast of western Sumatra at a depth of 481 meters. They studied terrestrial plant waxes, a layer on the plant’s surface protecting against dehydration and microbial attack, which are preserved in the sediment. It is possible to reconstruct past precipitation changes by measuring the stable hydrogen isotopic composition in terrestrial plant waxes because rainfall is the primary source of hydrogen stored in plant material. The method thus extends the comparatively short temporal coverage of directly measured climate data to times long past.
In the long term, changes in sea level were of minor importance to rainfall patterns in north western Sumatra
With the end of the last Ice Age came rising temperatures and melting polar ice sheets, which were accompanied by an increase in rainfall around Indonesia and many other regions of the world.. In contrast, the plant wax record from the study site in north western Sumatra reveals similarly high amounts of rainfall during both the Last Glacial Maximum and the Holocene. The amount of rainfall during the past 24,000 years seems to be linked to the level of exposure of the Sunda Shelf and in particular to the specific topography of the western edge of the region, rather than to changes in deglacial climate boundary conditions alone. “This is quite unexpected. Based on previous studies it was assumed that the entire region was much drier during the Last Glacial Maximum compared to present conditions,“ Niedermeyer concludes.
Pilot study focusing on a region vulnerable to climate change
Although the study highlights that long term changes in rainfall intensity are not always ’man-made,’ it does not necessarily mean that today's weather anomalies across the Indian Ocean rim countries and, in particular, their frequency, are not subject to human influence. The Indian Ocean region is home to a growing population, and possible adverse future climate conditions might spur political conflicts. The pilot study is a step towards detailed investigations that may be carried out in the future in this area. An enhanced understanding of the climatic phenomena, and their underlying mechanisms in this area, helps to increase the resolution of climate projections.
For more information please contact:
Dr. Eva Niedermeyer
LOEWE Biodiversity and Climate Research Centre (BiK-F)
Tel. +49 (0)69 7542 1882
LOEWE Biodiversity and Climate Research Centre (BiK-F),
Tel. +49 (0)69 7542 1838
LOEWE Biodiversität und Klima Forschungszentrum, Frankfurt am Main
With the objective of analyzing the complex interactions between biodiversity and climate, through a wide range of methods, the Biodiversität und Klima Forschungszentrum [Biodiversity and Climate Research Centre] (BiK‐F) has been funded since 2008 within the context of the Landes‐ Offensive zur Entwicklung Wissenschaftlichökonomischer Exzellenz (LOEWE) of the Land of Hessen. The Senckenberg Gesellschaft für Naturforschung and Goethe University in Frankfurt, as well as other directly involved partners, co‐operate closely with regional, national and international institutions in the fields of science, resource and environmental management, in order to develop projections for the future of scientific recommendations for sustainable action.
For further details, please visit www.bik‐f.de
Sabine Wendler | Senckenberg
New study reveals where MH370 debris more likely to be found
27.07.2016 | European Geosciences Union
Exploring one of the largest salt flats in the world
27.07.2016 | University of Massachusetts at Amherst
Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.
To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...
A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology
On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...
Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.
While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
15.07.2016 | Event News
15.07.2016 | Event News
11.07.2016 | Event News
27.07.2016 | Earth Sciences
27.07.2016 | Materials Sciences
27.07.2016 | Earth Sciences