Variations in high-altitude winds could be responsible for extreme weather conditions in parts of Europe, and the U.S.
Changes in air flow patterns around the Northern Hemisphere are believed to be linked to unseasonal weather such as heat waves and cold spells, a University of Exeter news release reported.
High-altitude winds normally blow from East to West in irregular patterns across the globe; the winds move from north to south in a wave-like pattern. These winds also suck up warm air from the tropics or cold air from the Arctic and carry them to other regions such as the U.S. They are also believed to have the ability to influence rainfall by "steering" storms in different directions.
New research suggests the development of these wave patterns could leave the Northern Hemisphere susceptible to different types of extreme weather.
"The impacts of large and slow moving atmospheric waves are different in different places. In some places amplified waves increase the chance of unusually hot conditions, and in others the risk of cold, wet or dry conditions," Doctor James Screen, a Mathematics Research Fellow at the University of Exeter and lead author of the study, said in the news release.
The study suggests that larger waves can trigger droughts in regions of central North America, Europe, central Asia, and western Asia that have been exposed to extended precipitation. It also shows that western North America and central Asia are more prone to heat waves while Eastern North America is more likely to experience a cold snap.
To make their findings the researchers looked at "land-based climate observations" to identify trends in abnormal temperatures and rainfall between the years of 1979 and 2012; they also how the wave patterns were linked to these events.
"The study revealed that these types of events are strongly related to well-developed wave patterns, and that these patterns increase the chance of heat waves in western North America and central Asia, cold outbreaks in eastern North America, droughts in central North America, Europe and central Asia, and wet spells in western Asia," co-author Professor Ian Simmonds, from the School of Earth Sciences at the University of Melbourne, said in the news release.
"The findings are very important for decision makers in assessing the risk of, and planning for the impacts of, extreme weather events in the future," he said.
