Reducing wind speed in many places in the United States can cause a lot of influence not only for the wind power industry, according to climate researchers in Iowa, USA.
Three Iowa State researchers contributed their insights into the North American climate model into a study published in the Journal of Geophysical Research - Atmospheres. The study was headed by Sara C. Pryor, professor of climate science at Indiana Blooming University. The results show that wind speeds across the United States have decreased by an average of 0.5% to 1% per year since 1973.
'The study found that throughout the United States, wind speed is declining - the situation in the East is more serious than the West, and especially in the Northeast and the Great Lakes area,' Gene Takle, a teacher. The professor specializes in geology, climate and agriculture science.
Takle said that in Iowa, the state's second largest wind power exploitation capacity, according to research results, the annual wind speed drops proportionately to the average reduction rate of the remaining regions.
The results of the study have stirred up newspapers across the United States. Most articles revolve around potential impacts on the wind industry.
But a group of climate researchers including Takle, Ray Arritt - agricultural professor, and Bill Gutowski - professor of geography and climate science, said the study also offers many other issues and questions. .
The study looked at 8 wind data packages from 1973 until 2005: measurements of wind speed obtained from instrumentation, combined data generated from actual measurements and climate models. on computers, with two other climate models. Iowa State researchers contributed to the North American climate model they had studied since the early 1990s. This is a common model that researchers around the world share and use.
Takle says there is not much consistency between actual measurements and models. The model closest to the most realistic measurements is the model used by Iowa state researchers.
However Gutowski said these differences are not surprising, since the study is only an initial test of the surface wind trend. He also added that these differences tell climate researchers that they still have a lot of work to do.
'We have already seen the trend of the wind speed being declining, and the question is still unanswered is whether this is part of global warming or something else,' Gutowski said. 'What we are studying is not a problem that is often taken care of. Most studies only pay attention to temperature or rainfall, not to surface wind. '
Researchers say that reduced surface winds may have enormous implications not only for the wind power industry.
For example, the wind still helps plants cool and airy. Lower wind speeds may mean higher field temperatures and lower crop yields.
Slow blowing wind also has the ability to cause dew to stay longer on plants, Takle said. This can lead to fungal problems and many other plant diseases, reducing yield. In urban areas, low wind speeds may mean increased temperatures and pollution levels, Iowa researchers said.
'Air pollution in major cities occurs when air is stagnant and high pressure,' Takle said. 'Less wind means less airflow and stagnant pollutants.'
Low wind speed is also a problem when the city faces heat, he said. The wind will not perform as well as the function of reducing the temperature as before, so the heat has a chance to accumulate and rise higher.
According to scientists, all of these effects, as well as the cause of wind speed reductions in the United States, need further study.
Takle offers three possible explanations for low wind speeds: one is the changes in the measurement method of scientists that lead to false results (although researchers have also taken into account this and made estimated errors); second, the study did not take into account changes in land use, such as urban infrastructure development or increased plant growth, reducing wind speed near measuring devices; three is the changing climate and one of the consequences is that the wind speed decreases.
According to Arritt, the results seem to support the hypothesis that climate change is affecting wind speeds.
'We have reason to think that global warming will reduce wind speed in subtropical and temperate regions,' Arritt said. 'But we want to confirm this theory with specific metrics, and the results that are currently obtained make us think this hypothesis is on the right track.'