By David Hosansky
An international team of scientists has demonstrated how powerful thunderstorm complexes over the U.S. Corn Belt are fueled by moisture rising from the region's fertile fields or just beneath them. The findings can lead to better and longer-term weather forecasts for this critical farming area as well as giving researchers new insights into improving computer models needed to better understand atmospheric processes.
The research, led by scientists at the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR), focuses on mesoscale convective systems (MCSs), which are complexes of thunderstorms that span 60 miles or more and persist for many hours. The paper concludes that natural reservoirs of shallow groundwater, coupled with irrigation systems and vast fields of crops across the Corn Belt, increase the frequency of these storm systems by 24–35%. The systems also persist about 10% longer.
MCSs are a critical weather feature of the Corn Belt, providing approximately 40–60% of precipitation during the growing season. Even as these potent storms deliver essential moisture to an agricultural region that produces more than a third of the world's corn, however, they also unleash destructive hazards, including flooding, hail, high winds, and tornadoes.
"Our findings provide a holistic view of how groundwater-crop-irrigation interactions influence the local atmosphere and enhance thunderstorms," said NSF NCAR scientist Zhe Zhang, the lead author. "This is important for better forecasting of severe weather for a major agricultural region and helping with long-term prediction of storm patterns weeks or even months in advance."
Zhang and his colleagues used advanced computer simulations and a specialized algorithm to determine the processes that are fueling the region's thunderstorms. The Corn Belt spans a dozen states in the Midwest and Great Plains, ranging from Ohio in the east to Nebraska in the west.
The study is published in Communications Earth & Environment. In addition to a team of NSF NCAR scientists, it was co-authored by scientists with the Institute for Atmospheric and Climate Science (ETH Zürich) in Switzerland, the Universidade de Santiago de Compostela in Galicia, Spain; and the Hong Kong University of Science and Technology.
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