Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Climate change signal detected in the Indian Ocean

The signature of climate change over the past 40 years has been identified in temperatures of the Indian Ocean near Australia.

“From ocean measurements and by analysing climate simulations we can see there are changes in features of the ocean that cannot be explained by natural variability,” said CSIRO oceanographer Dr Gael Alory.

“These oceanic changes are almost certainly linked to changes in the heat structure of the atmosphere and have led to a rise in water temperatures in the sub-tropical Indian Ocean of around two degrees celsius.

“At the same time, we are seeing changes in ocean circulation in tropical regions as a result of a long-term weakening of the Pacific Ocean trade winds. This affects sea surface temperature in regions relevant to the source and distribution of rainfall across southern Australia,” Dr Alory said.

The research – by Dr Alory, his CSIRO Wealth from Oceans National Research Flagship colleague, Dr Gary Meyers, and CSIRO Marine and Atmospheric’s Dr Susan Wijffels – has recently appeared in the journal, Geophysical Research Letters. The paper examines trends in Indian Ocean temperatures over 40 years that can help scientists and resource managers understand fluctuations in rainfall patterns over southern Australia.

The research, contributing to the Australian Climate Change Science Program and partly funded by the South East Australia Climate Initiative, combined access to ocean observations using the volunteer ‘ships of opportunity’ program and a set of models used by scientists in developing the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment. Thanks to the operators and crew of commercial ships, Australian scientists have access to a regular series of ocean measurements to a depth of 800 metres across the Indian Ocean.

“The cooling is occurring between Australia and Indonesia where the Indonesian throughflow emerges into the Indian Ocean and is linked to the observed weakening of Pacific Ocean trade-winds,”The team’s key findings were:

a general warming of the ocean surface indicating the influence of rising atmospheric temperatures;

a strong warming (about 2°C over 40 years) between 40°S and 50°S down to a depth of 800 metres;

and, sub-surface cooling in the tropics due to deep waters rising closer to the surface.

Dr Alory says the research confirmed a long-held view that temperature changes in the Pacific and Indian oceans can be partly explained by the effect of the ‘Indonesian throughflow’ – a system of currents which transports water between the oceans through the maze of straits and passages in the Indonesian Archipelago.

“The cooling is occurring between Australia and Indonesia where the Indonesian throughflow emerges into the Indian Ocean and is linked to the observed weakening of Pacific Ocean trade-winds,” he says. The models also helped to explain trends in the subtropical Indian Ocean temperatures and changes in relevant ocean features. In this area, the deep-reaching warming is due to a strengthening of westerly winds drawing a southward shift in ocean current patterns. These findings are consistent with research in the South Atlantic and South Pacific ocean basins.

He said that the change in atmospheric conditions altering ocean temperatures – weakening of Pacific Ocean trade winds and strengthening of westerly winds – have been mostly attributed to human activity: the production of aerosols (tiny atmospheric particles), ozone depletion, and greenhouse gases. Strengthening westerlies are related to changes in the Southern Annular Mode – an atmospheric feature similar to the El Nino Southern Oscillation and considered the dominant influence on Southern Hemisphere atmospheric variability.

Dr Alory said climate models used in the IPCC Fourth Assessment show that changes in westerly wind patterns are expected to intensify in a global warming scenario and to accentuate the southward shift in sub-tropical ocean circulation patterns.

Dr. Gael Alory | EurekAlert!
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

nachricht Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

New method increases energy density in lithium batteries

24.10.2016 | Power and Electrical Engineering

International team discovers novel Alzheimer's disease risk gene among Icelanders

24.10.2016 | Life Sciences

New bacteria groups, and stunning diversity, discovered underground

24.10.2016 | Life Sciences

More VideoLinks >>>