Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Call for network to monitor Southern Ocean current

20.08.2007
The senior science advisor to the World Climate Research Programme (WCRP) has called for the establishment of a Southern Hemisphere network of deep ocean moorings to detect any change in ocean circulation that may adversely influence global climate.

Background: Southern Ocean Current

In a commentary published in the journal Science today, Dr John Church of the Antarctic Climate and Ecosystem Cooperative Research Centre and CSIRO, through the Wealth from Oceans Flagship, said a Southern Hemisphere observing network is needed to complement a network of moorings now spanning the North Atlantic Ocean.

The North Atlantic moored network (at latitude 26ºN) provides measurements of the Gulf Stream – a significant feature in moderating European and North American climate by moving warm waters towards high latitudes.

It monitors two key elements of what is called the ‘North Atlantic overturning circulation’: the northward flow of near-surface, warm water which is controlled by a combination of surface winds and gradients of temperature and salinity, and; the southward flow of cold, deep water.

“An equivalent Southern Hemisphere monitoring network to measure changes in the Southern Ocean limb of the overturning circulation, where water mass changes have also been observed, is yet to be designed,” Dr Church said.

“However, the establishment of such a system in the Southern Hemisphere is critical to providing the additional data ocean scientists need to more accurately monitor any shifts in the global ocean circulation that influence world climate,” he said.

“A recent study suggests it would take several decades of observations to detect any trends in the circulation and a similar time frame to assess which if any other the models most accurately reflects reality,”

Dr Church said.In a paper published earlier this year in Science, Cunningham et al. estimate they can measure any variation in the annual average overturning to better than 10 per cent, which would be sufficient to detect any large scale abrupt transition in the overturning circulation. In another paper published in Nature in 2005, UK scientists (Bryden et al) used five decades of measurements to estimate changes of 30 per cent in the overturning circulation in the North Atlantic and a 20 per cent reduction in the amount of heat being transported to the region.

“Prior to the current observations, it was unclear how large and rapid the variations in this overturning circulation were,” Dr Church said. “The latest results show that the variation in the overturning over a year was as large as the changes previously observed by Bryden et al.

“Even though an assessment of the current generation of climate models indicate that a large abrupt transition is unlikely during the 21st Century, monitoring and understanding the variability will be critical to detecting any change and to improving models, thus allowing more reliable projections of climate change.

“A recent study suggests it would take several decades of observations to detect any trends in the circulation and a similar time frame to assess which if any other the models most accurately reflects reality,” Dr Church said.

“Verifying our climate projections and continuing to assess the stability of the overturning circulation remains a priority of the WCRP,” he said.

Download images at: Call for network to monitor Southern Ocean current.

Read more media releases in our Media Centre.

Background: Southern Ocean Current
One public image of climate change is a rapid and dramatic collapse of the northward flow of warm water to high latitudes, with possible serious implications for North American and European climate.

This warm water flows from the Florida Strait northward along the east coast of America as the Gulf Stream. After leaving the coast of North America, the warm water flows northeastward before it diverges, with some water continuing northward beyond Iceland and the remainder returning in a broad southward flow in the upper kilometre of the ocean.

Throughout its northward journey, the warm water loses heat to the atmosphere and becomes denser. The colder denser water sinks at high latitudes north of Iceland and returns southward at depths of 2-5 kilometres.

Two processes can prevent high-latitude water from sinking: surface warming and decreased salinity caused by freshwater runoff from rain and glacier meltwater from glaciers and the Greenland Ice Sheet. This would disrupt the overturning circulation.

Observations indicate there has been a freshening of the North Atlantic while climate change models in which carbon dioxide concentrations quadruple over 140 years project a decrease in the overturning circulation by 10-50 per cent.

Craig Macaulay | EurekAlert!
Further information:
http://www.csiro.au

More articles from Earth Sciences:

nachricht Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>