Recent weather extremes linked to high-altitude wind variations

June 23, 2014 by  
Filed under Wind Energy Tips

The results of a new study by researchers at the University of Exeter University of Melbourne, UK, show that variations in high-altitude wind patterns expose parts of Europe, Asia and the US to diverse extreme weather conditions.  The changes in air flow patterns around the Northern Hemisphere are a key influence on protracted spats of unseasonal weather.

The high altitude winds typically blow from west to east around Earth, meandering to the North and South in a wave-like path.  These wave patterns are responsible for drawing up either warm air from the tropics, or cold air from the Arctic, to Europe, Asia, or the US.  These winds can also manipulate rainfall by steering rain-laden storms.

The joint Exeter-Melbourne study has shown that the development of these wave patterns leaves certain Northern Hemisphere regions more susceptible to different types of prolonged, extreme weather.

“The impacts of large and slow moving atmospheric waves are different in different places,” said Dr. James Screen, a Mathematics Research Fellow at the University of Exeter and lead author of the study.  “In some places amplified waves increase the chance of unusually hot conditions, and in others the risk of cold, wet or dry conditions.”

The study showed that bigger waves can lead to droughts in central North America, Europe and central Asia, and western Asia exposed to prolonged wet spells.  Additionally, the study shows western North America and central Asia are more prone to heat waves, while eastern North America is more likely to experience prolonged outbreaks of cold.

The joint study used detailed land-based climate observations to categorize episodes of abnormal temperature and rainfall from 1979 to 2012 and then examined the wave patterns during these events.

According to North Carolina State University, the circulation of wind in the atmosphere is driven by the rotation of the earth and the incoming energy from the sun.  Wind circulates in each hemisphere in three distinct cells which help transport energy and heat from the equator to the poles.  The winds are driven by the energy from the sun at the surface as warm air rises and colder air sinks.

Comments are closed.