While scientists have predicted for years that the global climate will change in the future, an atmospheric scientist at the Illinois State Water Survey at the University of Illinois in Urbana-Champaign is working on a climate model at the regional scale to predict the impacts of climate change right here in Illinois.

A regional model may be particularly beneficial to crop producers in selecting which crops to grow, when to plant, and how to manage field operations, according to Xin-Zhong Liang, who works on nearly a dozen climate modeling projects. He also directs the Climate, Air Quality and Impact Modeling System (CAQIMS), a program to project future changes in climate and air quality and their impacts in Illinois.

World-wide climate models consider the effects of oceans, hurricanes, and other large-scale impacts on weather and climate to foresee the future of climate change. They also average weather conditions, such as temperature and precipitation, over a widespread area.

However, these models won't predict what may happen in central Illinois in 10 or 20 years from now because they don't take into account effects from lakes, rivers, crops, and other local factors.

Liang uses data from global models, but also adds localized information to formulate a narrower picture, "building piece by piece," said Liang. Information may include topography, land cover/use, soil structure, and gas/aerosol emissions.

Models on general circulation, regional climate, air quality, and other climate and environmental factors can also be combined to create a more integrated, comprehensive outcome.

To test the accuracy of the model in development, he looks at past climate events.

"In model building, you benefit from past observations," Liang said. "What happened in the past provides data for scientists to understand nature and formulate mathematical models to predict the future."

A model that can successfully reproduce past climate conditions is better positioned to provide future forecasts. For example, Liang expects his model to accurately "hindcast" two summer extreme climate events from the past—the 1988 drought and the 1993 flood in the Midwest, both of which resulted in several billion dollars in agricultural losses and property damages.

Once the model is fine-tuned, it will have practical applications for Illinoisans. Liang is working with civil engineers at the University of Illinois and the National Drought Mitigation Center on a NASA-funded project to assist farmers with decisions on when irrigation will be needed, given a predicted drought.

Also, predictions about how human-produced emissions might affect climate will be useful for city and community development planning.

In related research, Liang and his colleagues are working on the following projects:

• Impacts of global climate and emissions changes on U.S. air quality;
• Impacts of climate change on U.S. agricultural and invasive plant distributions;
• Reduction of uncertainty in future climate change projections by downscaling;
• Climate-crop interactions and crop yield predictions; and
• Seasonal-interannual climate predictions.