Sunday, August 7, 2011

Supercomputers may help predict climate changes locally

Renee Schoof in the Miami Herald via McClatchy Newspapers: Even a century ago, scientists working out equations on paper understood that gases in the atmosphere absorbed and emitted energy, keeping Earth from being a ball of ice. Today they use supercomputers to make increasingly refined predictions about how the Earth's climate will change. The new efforts take the question from global to local scale. Nations, states and communities have lots of climate-related questions: Should they divert water from one area to another? Build higher sea walls? Store and manage water the way Israel does today? Plan for many more 100-degree days in future summers?

"We can't answer those questions with the capabilities we have today. That's why we're using supercomputers to push the limits of what we understand and how well we can predict," said James Kinter. He's a professor in the climate dynamics Ph.D. program at George Mason University in Virginia and the director of the Center for Ocean-Land-Atmosphere Studies. "We know with a high degree of certainty that the planet is warming up, and so just on average every place is going to be warmer," Kinter said. "But nobody lives on the average."

...As computers improve, climate scientists can make increasingly better models... The National Center for Atmospheric Research today hosts one of the world's top computers for climate models, used by Kinter's group and many other scientists. Next year a better computer will open in a new facility in Cheyenne, Wyo. The current site couldn't house the next generation of computing, Buja said.

National Center for Atmospheric Research and Department of Energy scientists' models were major contributions to the 2007 report by the Intergovernmental Panel on Climate Change. Buja said they now were finishing models for the next international review of climate science, due in 2014. "There's a huge economic cost of responding to this," Buja said. "We need to make sure we're presenting as convincing a case as we can."...

Climate models are systems of differential equations based on the basic laws of physics, fluid motion, and chemistry. To “run” a model, scientists divide the planet into a 3-dimensional grid, apply the basic equations, and evaluate the results. Atmospheric models calculate winds, heat transfer, radiation, relative humidity, and surface hydrology within each grid and evaluate interactions with neighboring points. From NOAA

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