Slowing winds could have big implications on the farm
If you're full of hot air, some might say, you're windy. But, new research findings prove that analogy may not be true.
Declining wind speeds in parts of the United States could impact more than the wind power industry, say Iowa State University climate researchers who recently contributed their expertise in modeling North America's climate to a study to be published in the Journal of Geophysical Research -- Atmospheres. The study -- led by Sara C. Pryor, a professor of atmospheric science at Indiana University Bloomington -- found that wind speeds across the country have decreased by an average of .5% to 1% per year since 1973.
"The study found that across the country wind speeds were decreasing -- more in the East than in the West, and more in the Northeast and the Great Lakes," Iowa State professor of geological and atmospheric sciences and agronomy Gene Takle says in a university report.
In Iowa, a state that ranks second in the country for installed wind power capacity, Takle says the study found annual wind speed declines that matched the average for the rest of the country.
The study's findings made headlines across the country. Most of those stories focused on the potential implications for the wind power industry.
But Iowa State's team of climate researchers -- Takle; Ray Arritt, a professor of agronomy; and Bill Gutowski, a professor of geological and atmospheric sciences -- say the study raised other issues and questions, too.
The study looked at eight sets of wind data going back to 1973 and up to 2005: actual wind speed measurements from anemometers; a hybrid of measurements and computerized climate models; and two different regional climate models. Iowa State researchers contributed a regional model of North America's climate they've worked with since the early 1990s. It's a community model that researchers across the globe share and use. The Iowa State researchers have used the model to run long-term climate simulations.
Takle said there wasn't a lot of agreement between the measurements and the various models. The model that most closely matched the measurements was the one used by the Iowa State researchers.
Gutowski said the differences aren't surprising because the study was an initial examination of surface wind trends. He also says those differences tell climate researchers they have more work to do.
"We see this trend toward slower wind speeds and our unanswered question is whether this is part of global warming or something else," Gutowski says. "What we're poking into here is not something that's commonly explored. Most studies look at temperature and precipitation, not surface winds."
But the researchers say slower surface winds can have significant impacts beyond the wind power industry.
Crops, for example, depend on the wind for ventilation and cooling. Slower winds could mean higher field temperatures and less productive crops.
Slower winds could also mean more dew covering crops for longer periods, Takle says. That could mean problems with fungus and plant disease. That could also lead to lower yields at harvest time.