Simulator Could Predict Long-term Weather Patterns

People in a hurry who leave the house on a sunny morning minus their umbrella only to find themselves drenched by an afternoon downpour will have no excuses if scientists in Japan succeed in an ambitious quest to forecast bad weather.

The country's science ministry has unveiled plans to harness the power of the Earth Simulator, until recently the world's fastest supercomputer, to predict the weather up to 30 years into the future.

The ministry, which will invest a reported 10bn yen (£46m) in the project over the next five years, hopes to harness the power of the vast simulator, which occupies a warehouse the size of four tennis courts in Yokohama, south of Tokyo, to calculate the long-term patterns, incorporating atmospheric pressure, air temperatures, ocean currents and sea temperatures.

Scientists should be able to use the data to map the routes taken by typhoons, heatwaves and droughts, and potentially spare millions from death and disease.

"Now we can see what areas are at risk and start thinking about what kind of measures to take," Tomonori Otake, of the ministry's earth environment bureau, told Reuters.

The ministry has invited bids from researchers and hopes to have the project up and running by next spring.

The centre has made impressive advances in forecasting extreme weather patterns. It recently predicted the formation of a typhoon five days in advance, two days earlier than the best forecast from Japan's meteorological agency.

Introduced in 2002, the Earth Simulator was the fastest supercomputer in the world until it was overtaken two years later by IBM's Blue Gene. However, the $350m (£190m) Japanese supercomputer can still perform 35.6 trillion calculations a second.

But its success will depend less on the hardware and more on the software being developed by experts at the Earth Simulator centre. "It all depends on the simulation model," Kunihiko Watanabe, a research programme director at the centre, told the Guardian.

"It's not really about the computer's specifications. Even if we use a much larger computer, if the simulation code is not quite right then the results will still be wrong."

Researchers are constantly improving the simulation model in an effort to incorporate new factors such as social and economic change in rapidly developing countries such as China that affect, for example, carbon-dioxide emissions, Mr Watanabe said.

"Having said that, we are optimistic that we can make more precise predictions in a few years' time," he added.

By predicting the arrival of typhoons, storms, droughts and other extreme weather patterns, at-risk areas will have time to prepare and others the opportunity to send financial and material aid in advance.

"If we succeed in making forecasts a few days in advance we can avoid disasters, but if we can predict seasonal patterns and, for instance, tell farmers in the winter that they are facing an unusually hot summer, they can prepare their crops accordingly and we can alleviate food shortages around the world," Mr Watanabe said.

The ministry hopes to use the model to forecast global climate change up to 300 years into the future that pinpoint small areas anywhere in the world.

Even so, the science ministry's advice to anyone planning a day out 30 years from now is simple: if in doubt, take an umbrella.

"Just like the daily forecasts, we can't give a percentage for how accurate they are," Mr Otake said.