Supercomputer climate model whips up a storm


Virtual hurricanes have appeared in computer models of the Earth’s climate for the first time. The swirling storms are visible in the first results from the Earth Simulator in Yokohama, Japan – the world’s fastest supercomputer. The results, being presented at a workshop in Cambridge, UK, on Wednesday, are “really quite staggering” says Julia Slingo, Director of the Centre for Global Atmospheric Modelling at the University of Reading, UK.

Whereas most climate models divide the Earth into blocks measuring hundreds of kilometres across, the powerful Earth Simulator can run models with cells as small as 10 kilometres. This means that detailed features of the weather – such as tropical storms – can be included. In one sequence from the model, says Slingo, “you can see a typhoon going up to Japan and it even has a little eye”.

Weather forecasters already use high-resolution models to predict how hurricanes will evolve, but they can only look a few days into the future. The vast computing power of the Earth Simulator means it can simulate years of climate, which is vital to predicting how global warming will affect our weather.

For example, with hurricanes in the models, scientists can work out whether these ferocious storms will become more frequent as the planet gets hotter. Historical data suggests that there is no upward trend in the number of hurricanes, but only the climate models can predict the future.

Past and future

With more computer power, scientists can also include more elements of the Earth’s climate system, such as the oceans, the atmosphere, their chemistry and the carbon cycle.

This should make forecasts of future temperature rises more reliable. Keiko Takahashi, who works at the Earth Simulator Centre, says they have already carried out several experiments that look 50 years ahead.

Other scientists at the workshop are eagerly waiting for their chance to use the Earth Simulator, which was officially opened in March 2002. Paul Valdes, a paleoclimatologist from the University of Bristol, UK, is one of those in the queue and he wants to study the past, rather than the future climate.

“We will model the whole of the last 21,000 years,” says Valdes. Then he will compare the data generated to real world data from ice cores, tree rings and stalactites to see if they match up. “The next few years promises to be a very exciting time for paleoclimate modelling” he says.

The Earth Simulator results presented at the meeting are only the beginning, agrees Slingo. “It is like the Hubble Telescope – it’s a piece of kit, and we are just learning how to use it.”
(New Scientist – Reed Business Information Ltd. The World’s No.1 Science & Technology News Service)