Article: Cloud concern

Tuesday June 30, 2009

By CATHERINE HORNBY

Scientists probe how clouds react to climate change.

WEARING 3-D viewing goggles, scientists peer at virtual pink, blue and purple clouds billowing in cyberspace at a research laboratory in the Dutch city of Delft. By tracking how particles move in and around computer-simulated clouds, they hope to shed light on one of the unknowns of climate forecasting: how these masses of water droplets and ice crystals influence changing temperatures.

The research, at Delft University of Technology, was undertaken because of the growing urgency for scientists to improve ways of forecasting climate change.

Researcher Thijs Heus, a former student at the laboratory, explained that he used the simulations to chart data such as the speed, temperature and lifespan of clouds.

"We number the clouds and we track them from their infancy through their entire life cycle," he said. "We can also give them colour to see if dust particles are moving up or down within and around the clouds," Heus added, demonstrating ways to observe clouds in more detail by magnifying their virtual images on screen.

Haleigh Lehfeldt and her sister Shyann holding on to each other as a hard-edged storm cloud moves through North Dakota. Rain started falling a few minutes later.

Using powerful computer technology and satellite data, the scientists at Delft hope to gain a more accurate picture of how clouds react to climate change.

"There is enormous uncertainty about what clouds will do, and how they will respond to a changing climate and that is a major impediment for climate predictions," said Harm Jonker, associate professor at the university.

Projections of how much the earth's temperature will rise in the next century vary from 1.1 to 6.4°C, with the effect of clouds remaining one of the main sources of uncertainty, the United Nations climate panel found in its 2007 climate assessment report.

Jonker said it was unclear, for example, whether there would be more or fewer of low clouds such as cumulus in warmer conditions, which would affect the rate of global warming because of their role in reflecting sunlight away from the earth.

"In a warmer climate, if there is more evaporation, that could lead to more of the lower clouds, which could diminish the effects of climate warming," said Jonker.

He added warm air could hold more water vapour than cold air before it formed clouds, so there might be fewer low clouds as the earth heated up, which would accelerate global warming.

Rising sea levels and increased risk of droughts, flooding and species extinction are some of the likely effects of global warming, caused mainly by emissions of greenhouse gases from burning fossil fuels.

European and Japanese space scientists have turned their attention to clouds because of the pressing need for research. A �350mil (RM1.7bil) satellite project, due for launch in 2014, aims to improve understanding of the role they play in climate regulation. The project, known as EarthCARE, is being assembled mainly by the Astrium unit of the European aerospace group EADS and combines the technology of existing cloud observation satellites with new instruments for a more accurate picture.

"It's much more complex then anything that's flying at present," said Stephen Briggs of the European Space Agency. "The difficulty with clouds is that you can't see into them, so you have to find ways of looking into their three-dimensional structure, such as with radar systems." � Reuters

This article was taken from: The Star Online: Lifestyle: Focus 30 June 2009