 |
Just what, then, can the world’s fastest supercomputer do when tasked with forecasting climate change? According to Kikuchi, “Conventional global-climate simulations divide the planet into a grid of 100kmx100km squares, but these divisions are too large to generate precise forecasts, and forecasts based on them are quite poor at fully incorporating the impact of local phenomena such as typhoons and earthquakes. In contrast, the Earth Simulator can run simulations based on a grid of 10km x 10km squares, which dramatically increases the level of forecasting precision.”
While explaining this, Kikuchi points out two images, both global oceanic surface temperature simulations. One is based on the 100km mesh, the other on a 10-km mesh. The difference is immediately apparent even to the untrained eye. The 100-km resolution mesh image shows a mosaic of colors indicating surface temperatures while the 10-km resolution version paints the natural curved lines of the flow of oceanic currents. Simulations of this level of precision were virtually impossible before. It takes the Earth Simulator just hours to run a one-year simulation using a 10-km resolution, but it would take other supercomputers 300–400 times longer.
“It doesn’t do much good if it takes you five years to run a 10-year simulation,” says Kikuchi. “With the Earth Simulator, you can run a 10-year simulation in a matter of days. That is the really exciting part. With this supercomputer, you can develop highly accurate predictions for what size of typhoon might develop where, and what path it might take, or even how global warming might progress and what impacts it could have after 10 or 20 years. You could almost say there’s no climate simulation you couldn’t run on this system.”
Yet one cannot simply run such simulations without extensive preparation. Data must be collected, and models constructed and verified. JAMSTEC researchers are already working on parallel tracks to develop and verify global-scale models for the ocean and the atmosphere. When they finish, the two models are to be coupled, resulting in a single, three-dimensional global model that shows both oceanic and atmospheric change. Only then can full simulations be run, and researchers expect this model-development process to take another three to four years. Put another way, three to four years from now, we will be able to get an accurate picture of how global warming will develop. Having an accurate forecast would make it much easier to develop appropriate environmental policies. Over the coming years, Earth simulations may well enable us to significantly reduce damage from phenomena such as abnormal weather patterns, typhoons, and droughts.
 |
 |
 |
|
The result of ocean-surface temperature simulation. (Courtesy of JAMSTEC) |
|
