‘Asian haze’ impacts on Australian rainfall

“Until now, there has been ample evidence that these particles have important effects on climate in the Northern Hemisphere but little such evidence in the Southern Hemisphere,” says CSIRO Marine and Atmospheric Research scientist, Dr Leon Rotstayn.

“What we have seen in our latest climate simulations is that the ‘Asian haze’ is having an effect on the Australian hydrological cycle and generated increasing rainfall and cloudiness since 1950, especially over northwest and central Australia. The effect occurs because the haze cools the Asian continent and nearby oceans, and thereby alters the delicate balance of temperature and winds between Asia and Australia. It has nothing to do with Asian pollution being transported directly over Australia.”

Dr Rotstayn says this implies that decreasing pollution in Asia later this century could reverse this effect and lead to an increase in Australian drying trends.

“We are really at the beginning of understanding the trends but sooner or later these emissions will be cleaned up and then a trend of increasing rainfall in the northwest and centre could be reversed. This is potentially serious, because the northwest and centre are the only parts of Australia where rainfall has been increasing in recent decades.”

Dr Rotstayn stresses that climate modelling is a valuable tool for teasing out what is actually causing weather trends, rather than simply assuming that these trends are all related to greenhouse gases.

At a time when Australian science agencies are investing in new climate forecasting capabilities, the research – to be published early in 2007 in the Journal of Geophysical Research – increases confidence in the accuracy of future climate simulations for Australia.

An aerosol is a haze of particles in the atmosphere. Dr Rotstayn says representing aerosols in climate models and understanding their influence on cloud formation and rainfall is one of the biggest challenges facing climate scientists.

“Because the cooling effect of aerosol pollution is possibly comparable to the warming effect of increased levels of carbon dioxide, the message from this research is that aerosols are an essential inclusion if we are to accurately describe present and future Australian climate,” he says.

The new research is based on simulations performed with a new low-resolution version of CSIRO’s global climate model – including a treatment of aerosols from both natural and human-induced sources.

Dr Rotstayn was lead author of the paper with contributing scientists from: the Cooperative Research Centre for Greenhouse Accounting at the Australian National University; the University of Michigan’s Department of Atmospheric, Oceanic and Space Sciences; and, the U.S. National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory in Princeton

Media Contact

Craig Macaulay EurekAlert!

More Information:

http://www.csiro.au

All latest news from the category: Earth Sciences

Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.

Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.

Back to home

Comments (0)

Write a comment

Newest articles

The Sound of the Perfect Coating

Fraunhofer IWS Transfers Laser-based Sound Analysis of Surfaces into Industrial Practice with “LAwave”. Sound waves can reveal surface properties. Parameters such as surface or coating quality of components can be…

Customized silicon chips

…from Saxony for material characterization of printed electronics. How efficient are new materials? Does changing the properties lead to better conductivity? The Fraunhofer Institute for Photonic Microsystems IPMS develops and…

Acetylation: a Time-Keeper of glucocorticoid Sensitivity

Understanding the regulatory mechanism paves the way to enhance the effectiveness of anti-inflammatory therapies and to develop strategies to counteract the negative effects of stress- and age-related cortisol excess. The…

Partners & Sponsors